diff --git a/.gitignore b/.gitignore
index 0517ac2..36befc4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
+bin
 target
 .classpath
 .settings
diff --git a/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/logical/UnnestOperator.java b/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/logical/UnnestOperator.java
index 7efee75..b9ac62f 100644
--- a/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/logical/UnnestOperator.java
+++ b/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/logical/UnnestOperator.java
@@ -23,12 +23,22 @@
 import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalOperatorTag;
 import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable;
 import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.IVariableTypeEnvironment;
+import edu.uci.ics.hyracks.algebricks.core.algebra.properties.VariablePropagationPolicy;
 import edu.uci.ics.hyracks.algebricks.core.algebra.typing.ITypingContext;
 import edu.uci.ics.hyracks.algebricks.core.algebra.visitors.ILogicalOperatorVisitor;
 
 public class UnnestOperator extends AbstractUnnestOperator {
 
     private LogicalVariable positionalVariable;
+
+    /**
+     * Used to set the position offset for positional variable
+     */
+    private ILogicalExpression positionOffsetExpr;
+
+    /**
+     * Specify the type of the positional variable
+     */
     private Object positionalVariableType;
 
     public UnnestOperator(LogicalVariable variable, Mutable<ILogicalExpression> expression) {
@@ -67,6 +77,14 @@
         return positionalVariableType;
     }
 
+    public void setPositionOffsetExpr(ILogicalExpression posOffsetExpr) {
+        this.positionOffsetExpr = posOffsetExpr;
+    }
+
+    public ILogicalExpression getPositionOffsetExpr() {
+        return this.positionOffsetExpr;
+    }
+
     @Override
     public <R, T> R accept(ILogicalOperatorVisitor<R, T> visitor, T arg) throws AlgebricksException {
         return visitor.visitUnnestOperator(this, arg);
@@ -88,4 +106,24 @@
         }
         return env;
     }
+
+    @Override
+    public VariablePropagationPolicy getVariablePropagationPolicy() {
+        return new VariablePropagationPolicy() {
+
+            @Override
+            public void propagateVariables(IOperatorSchema target, IOperatorSchema... sources)
+                    throws AlgebricksException {
+                if (sources.length > 0) {
+                    target.addAllVariables(sources[0]);
+                }
+                for (LogicalVariable v : variables) {
+                    target.addVariable(v);
+                }
+                if (positionalVariable != null) {
+                    target.addVariable(positionalVariable);
+                }
+            }
+        };
+    }
 }
\ No newline at end of file
diff --git a/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/logical/visitors/FDsAndEquivClassesVisitor.java b/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/logical/visitors/FDsAndEquivClassesVisitor.java
index cebddee..3a2617f 100644
--- a/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/logical/visitors/FDsAndEquivClassesVisitor.java
+++ b/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/logical/visitors/FDsAndEquivClassesVisitor.java
@@ -404,7 +404,8 @@
     @Override
     public Void visitRunningAggregateOperator(RunningAggregateOperator op, IOptimizationContext ctx)
             throws AlgebricksException {
-        propagateFDsAndEquivClasses(op, ctx);
+        ctx.putEquivalenceClassMap(op, new HashMap<LogicalVariable, EquivalenceClass>());
+        ctx.putFDList(op, new ArrayList<FunctionalDependency>());
         return null;
     }
 
@@ -646,4 +647,4 @@
         return null;
     }
 
-}
+}
\ No newline at end of file
diff --git a/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/HashPartitionMergeExchangePOperator.java b/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/HashPartitionMergeExchangePOperator.java
index 9955a63..3f1aae2 100644
--- a/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/HashPartitionMergeExchangePOperator.java
+++ b/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/HashPartitionMergeExchangePOperator.java
@@ -44,9 +44,11 @@
 import edu.uci.ics.hyracks.algebricks.core.jobgen.impl.JobGenContext;
 import edu.uci.ics.hyracks.algebricks.data.IBinaryComparatorFactoryProvider;
 import edu.uci.ics.hyracks.algebricks.data.IBinaryHashFunctionFactoryProvider;
+import edu.uci.ics.hyracks.algebricks.data.INormalizedKeyComputerFactoryProvider;
 import edu.uci.ics.hyracks.api.dataflow.IConnectorDescriptor;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryHashFunctionFactory;
+import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputerFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.ITuplePartitionComputerFactory;
 import edu.uci.ics.hyracks.api.job.IConnectorDescriptorRegistry;
 import edu.uci.ics.hyracks.dataflow.common.data.partition.FieldHashPartitionComputerFactory;
@@ -142,27 +144,32 @@
         int n = orderColumns.size();
         int[] sortFields = new int[n];
         IBinaryComparatorFactory[] comparatorFactories = new IBinaryComparatorFactory[n];
-        {
-            int j = 0;
-            for (OrderColumn oc : orderColumns) {
-                LogicalVariable var = oc.getColumn();
-                sortFields[j] = opSchema.findVariable(var);
-                Object type = env.getVarType(var);
-                IBinaryComparatorFactoryProvider bcfp = context.getBinaryComparatorFactoryProvider();
-                comparatorFactories[j] = bcfp.getBinaryComparatorFactory(type, oc.getOrder() == OrderKind.ASC);
-                j++;
+
+        INormalizedKeyComputerFactoryProvider nkcfProvider = context.getNormalizedKeyComputerFactoryProvider();
+        INormalizedKeyComputerFactory nkcf = null;
+
+        int j = 0;
+        for (OrderColumn oc : orderColumns) {
+            LogicalVariable var = oc.getColumn();
+            sortFields[j] = opSchema.findVariable(var);
+            Object type = env.getVarType(var);
+            IBinaryComparatorFactoryProvider bcfp = context.getBinaryComparatorFactoryProvider();
+            comparatorFactories[j] = bcfp.getBinaryComparatorFactory(type, oc.getOrder() == OrderKind.ASC);
+            if (j == 0 && nkcfProvider != null && type != null) {
+                nkcf = nkcfProvider.getNormalizedKeyComputerFactory(type, oc.getOrder() == OrderKind.ASC);
             }
+            j++;
         }
 
         IConnectorDescriptor conn = new MToNPartitioningMergingConnectorDescriptor(spec, tpcf, sortFields,
-                comparatorFactories);
+                comparatorFactories, nkcf);
         return new Pair<IConnectorDescriptor, TargetConstraint>(conn, null);
     }
-    
+
     public List<LogicalVariable> getPartitionFields() {
         return partitionFields;
     }
-    
+
     public List<OrderColumn> getOrderColumns() {
         return orderColumns;
     }
diff --git a/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/PreclusteredGroupByPOperator.java b/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/PreclusteredGroupByPOperator.java
index 51b009f..bcd998d 100644
--- a/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/PreclusteredGroupByPOperator.java
+++ b/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/PreclusteredGroupByPOperator.java
@@ -24,6 +24,7 @@
 import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalExpression;
 import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
 import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalExpressionTag;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalOperatorTag;
 import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable;
 import edu.uci.ics.hyracks.algebricks.core.algebra.base.PhysicalOperatorTag;
 import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.VariableReferenceExpression;
@@ -34,6 +35,7 @@
 import edu.uci.ics.hyracks.algebricks.core.jobgen.impl.JobGenHelper;
 import edu.uci.ics.hyracks.algebricks.runtime.base.AlgebricksPipeline;
 import edu.uci.ics.hyracks.algebricks.runtime.operators.aggreg.NestedPlansAccumulatingAggregatorFactory;
+import edu.uci.ics.hyracks.algebricks.runtime.operators.aggreg.NestedPlansRunningAggregatorFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
 import edu.uci.ics.hyracks.api.job.IOperatorDescriptorRegistry;
@@ -76,13 +78,19 @@
         }
         // compile subplans and set the gby op. schema accordingly
         AlgebricksPipeline[] subplans = compileSubplans(inputSchemas[0], gby, opSchema, context);
-        IAggregatorDescriptorFactory aggregatorFactory = new NestedPlansAccumulatingAggregatorFactory(subplans, keys,
-                fdColumns);
+        IAggregatorDescriptorFactory aggregatorFactory;
+
+        if (((AbstractLogicalOperator) (gby.getNestedPlans().get(0).getRoots().get(0).getValue())).getOperatorTag() == LogicalOperatorTag.RUNNINGAGGREGATE) {
+            aggregatorFactory = new NestedPlansRunningAggregatorFactory(subplans, keys, fdColumns);
+        } else {
+            aggregatorFactory = new NestedPlansAccumulatingAggregatorFactory(subplans, keys, fdColumns);
+        }
 
         IOperatorDescriptorRegistry spec = builder.getJobSpec();
         IBinaryComparatorFactory[] comparatorFactories = JobGenHelper.variablesToAscBinaryComparatorFactories(
                 columnList, context.getTypeEnvironment(op), context);
-        RecordDescriptor recordDescriptor = JobGenHelper.mkRecordDescriptor(context.getTypeEnvironment(op), opSchema, context);
+        RecordDescriptor recordDescriptor = JobGenHelper.mkRecordDescriptor(context.getTypeEnvironment(op), opSchema,
+                context);
 
         PreclusteredGroupOperatorDescriptor opDesc = new PreclusteredGroupOperatorDescriptor(spec, keys,
                 comparatorFactories, aggregatorFactory, recordDescriptor);
diff --git a/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/RunningAggregatePOperator.java b/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/RunningAggregatePOperator.java
index 21def02..956c74f 100644
--- a/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/RunningAggregatePOperator.java
+++ b/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/RunningAggregatePOperator.java
@@ -62,22 +62,7 @@
     @Override
     public PhysicalRequirements getRequiredPropertiesForChildren(ILogicalOperator op,
             IPhysicalPropertiesVector reqdByParent) {
-        IPartitioningProperty pp = null;
-        RunningAggregateOperator ragg = (RunningAggregateOperator) op;
-        for (Mutable<ILogicalExpression> exprRef : ragg.getExpressions()) {
-            StatefulFunctionCallExpression f = (StatefulFunctionCallExpression) exprRef.getValue();
-            IPartitioningProperty p = f.getRequiredPartitioningProperty();
-            if (p != null) {
-                if (pp == null) {
-                    pp = p;
-                } else {
-                    throw new IllegalStateException("Two stateful functions want to set partitioning requirements: "
-                            + pp + " and " + p);
-                }
-            }
-        }
-        StructuralPropertiesVector[] r = new StructuralPropertiesVector[] { new StructuralPropertiesVector(pp, null) };
-        return new PhysicalRequirements(r, IPartitioningRequirementsCoordinator.NO_COORDINATION);
+        return emptyUnaryRequirements();
     }
 
     @Override
diff --git a/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/SortMergeExchangePOperator.java b/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/SortMergeExchangePOperator.java
index dc345ac..b03b99d 100644
--- a/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/SortMergeExchangePOperator.java
+++ b/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/SortMergeExchangePOperator.java
@@ -39,9 +39,11 @@
 import edu.uci.ics.hyracks.algebricks.core.jobgen.impl.JobGenContext;
 import edu.uci.ics.hyracks.algebricks.data.IBinaryComparatorFactoryProvider;
 import edu.uci.ics.hyracks.algebricks.data.IBinaryHashFunctionFactoryProvider;
+import edu.uci.ics.hyracks.algebricks.data.INormalizedKeyComputerFactoryProvider;
 import edu.uci.ics.hyracks.api.dataflow.IConnectorDescriptor;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryHashFunctionFactory;
+import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputerFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.ITuplePartitionComputerFactory;
 import edu.uci.ics.hyracks.api.job.IConnectorDescriptorRegistry;
 import edu.uci.ics.hyracks.dataflow.common.data.partition.FieldHashPartitionComputerFactory;
@@ -128,6 +130,10 @@
         IBinaryComparatorFactory[] comps = new IBinaryComparatorFactory[n];
         IBinaryHashFunctionFactory[] hashFuns = new IBinaryHashFunctionFactory[n];
         IVariableTypeEnvironment env = context.getTypeEnvironment(op);
+
+        INormalizedKeyComputerFactoryProvider nkcfProvider = context.getNormalizedKeyComputerFactoryProvider();
+        INormalizedKeyComputerFactory nkcf = null;
+
         for (int i = 0; i < n; i++) {
             sortFields[i] = opSchema.findVariable(sortColumns[i].getColumn());
             Object type = env.getVarType(sortColumns[i].getColumn());
@@ -135,9 +141,12 @@
             comps[i] = bcfp.getBinaryComparatorFactory(type, sortColumns[i].getOrder() == OrderKind.ASC);
             IBinaryHashFunctionFactoryProvider bhffp = context.getBinaryHashFunctionFactoryProvider();
             hashFuns[i] = bhffp.getBinaryHashFunctionFactory(type);
+            if (i == 0 && nkcfProvider != null && type != null) {
+                nkcf = nkcfProvider.getNormalizedKeyComputerFactory(type, sortColumns[i].getOrder() == OrderKind.ASC);
+            }
         }
         ITuplePartitionComputerFactory tpcf = new FieldHashPartitionComputerFactory(sortFields, hashFuns);
-        IConnectorDescriptor conn = new MToNPartitioningMergingConnectorDescriptor(spec, tpcf, sortFields, comps);
+        IConnectorDescriptor conn = new MToNPartitioningMergingConnectorDescriptor(spec, tpcf, sortFields, comps, nkcf);
         return new Pair<IConnectorDescriptor, TargetConstraint>(conn, TargetConstraint.ONE);
     }
 
diff --git a/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/UnnestPOperator.java b/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/UnnestPOperator.java
index bf45e18..bf2f68a 100644
--- a/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/UnnestPOperator.java
+++ b/algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/physical/UnnestPOperator.java
@@ -30,6 +30,7 @@
 import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.UnnestOperator;
 import edu.uci.ics.hyracks.algebricks.core.jobgen.impl.JobGenContext;
 import edu.uci.ics.hyracks.algebricks.core.jobgen.impl.JobGenHelper;
+import edu.uci.ics.hyracks.algebricks.runtime.base.IScalarEvaluatorFactory;
 import edu.uci.ics.hyracks.algebricks.runtime.base.IUnnestingEvaluatorFactory;
 import edu.uci.ics.hyracks.algebricks.runtime.operators.std.UnnestRuntimeFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
@@ -57,10 +58,7 @@
             IOperatorSchema opSchema, IOperatorSchema[] inputSchemas, IOperatorSchema outerPlanSchema)
             throws AlgebricksException {
         UnnestOperator unnest = (UnnestOperator) op;
-        if (unnest.getPositionalVariable() != null) {
-            throw new AlgebricksException("Cannot generate runtime for unnest with positional variable "
-                    + unnest.getPositionalVariable());
-        }
+
         int outCol = opSchema.findVariable(unnest.getVariable());
         ILogicalExpression unnestExpr = unnest.getExpressionRef().getValue();
         IExpressionRuntimeProvider expressionRuntimeProvider = context.getExpressionRuntimeProvider();
@@ -79,8 +77,18 @@
         UnnestingFunctionCallExpression agg = (UnnestingFunctionCallExpression) unnestExpr;
         IUnnestingEvaluatorFactory unnestingFactory = expressionRuntimeProvider.createUnnestingFunctionFactory(agg,
                 context.getTypeEnvironment(op.getInputs().get(0).getValue()), inputSchemas, context);
+
+        // for position offset
+        ILogicalExpression posOffsetExpr = unnest.getPositionOffsetExpr();
+        IScalarEvaluatorFactory posOffsetExprEvalFactory = null;
+        if (posOffsetExpr != null) {
+            posOffsetExprEvalFactory = expressionRuntimeProvider.createEvaluatorFactory(posOffsetExpr,
+                    context.getTypeEnvironment(op.getInputs().get(0).getValue()), inputSchemas, context);
+        }
+
         int[] projectionList = JobGenHelper.projectAllVariables(opSchema);
-        UnnestRuntimeFactory unnestRuntime = new UnnestRuntimeFactory(outCol, unnestingFactory, projectionList);
+        UnnestRuntimeFactory unnestRuntime = new UnnestRuntimeFactory(outCol, unnestingFactory, projectionList,
+                unnest.getPositionalVariable() != null, posOffsetExprEvalFactory);
         RecordDescriptor recDesc = JobGenHelper.mkRecordDescriptor(context.getTypeEnvironment(op), opSchema, context);
         builder.contributeMicroOperator(unnest, unnestRuntime, recDesc);
         ILogicalOperator src = unnest.getInputs().get(0).getValue();
diff --git a/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/EnforceOrderByAfterSubplan.java b/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/EnforceOrderByAfterSubplan.java
index a684bc9..02e090d 100644
--- a/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/EnforceOrderByAfterSubplan.java
+++ b/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/EnforceOrderByAfterSubplan.java
@@ -104,6 +104,10 @@
                     foundTarget = false;
                     break;
                 }
+                if(child.getOperatorTag() == LogicalOperatorTag.GROUP){
+                    foundTarget = false;
+                    break;
+                }
                 if (orderSensitiveOps.contains(child.getOperatorTag())) {
                     orderSensitive = true;
                 }
diff --git a/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/EnforceStructuralPropertiesRule.java b/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/EnforceStructuralPropertiesRule.java
index 98606f1..810defc 100644
--- a/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/EnforceStructuralPropertiesRule.java
+++ b/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/EnforceStructuralPropertiesRule.java
@@ -270,6 +270,8 @@
             // Now, transfer annotations from the original sort op. to this one.
             AbstractLogicalOperator transferTo = nextOp;
             if (transferTo.getOperatorTag() == LogicalOperatorTag.EXCHANGE) {
+                // 
+                // remove duplicate exchange operator
                 transferTo = (AbstractLogicalOperator) transferTo.getInputs().get(0).getValue();
             }
             transferTo.getAnnotations().putAll(op.getAnnotations());
@@ -345,6 +347,13 @@
             LocalOrderProperty orderProp = (LocalOrderProperty) dlvd.get(j);
             returnedProperties.add(new OrderColumn(orderProp.getColumn(), orderProp.getOrder()));
         }
+        // maintain other order columns after the required order columns
+        if(returnedProperties.size() != 0){
+            for(int j = prefix + 1; j < dlvdCols.size(); j++){
+                LocalOrderProperty orderProp = (LocalOrderProperty) dlvd.get(j);
+                returnedProperties.add(new OrderColumn(orderProp.getColumn(), orderProp.getOrder()));
+            }
+        }
         return returnedProperties;
     }
 
diff --git a/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/IntroHashPartitionMergeExchange.java b/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/IntroHashPartitionMergeExchange.java
index af11b70..e702d9f 100644
--- a/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/IntroHashPartitionMergeExchange.java
+++ b/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/IntroHashPartitionMergeExchange.java
@@ -28,6 +28,7 @@
 import edu.uci.ics.hyracks.algebricks.core.algebra.operators.physical.HashPartitionMergeExchangePOperator;
 import edu.uci.ics.hyracks.algebricks.core.algebra.operators.physical.SortMergeExchangePOperator;
 import edu.uci.ics.hyracks.algebricks.core.algebra.properties.OrderColumn;
+import edu.uci.ics.hyracks.algebricks.core.algebra.util.OperatorPropertiesUtil;
 import edu.uci.ics.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule;
 
 public class IntroHashPartitionMergeExchange implements IAlgebraicRewriteRule {
@@ -42,7 +43,8 @@
             throws AlgebricksException {
         AbstractLogicalOperator op1 = (AbstractLogicalOperator) opRef.getValue();
         if (op1.getPhysicalOperator() == null
-                || op1.getPhysicalOperator().getOperatorTag() != PhysicalOperatorTag.HASH_PARTITION_EXCHANGE) {
+                || (op1.getPhysicalOperator().getOperatorTag() != PhysicalOperatorTag.HASH_PARTITION_EXCHANGE && op1
+                        .getPhysicalOperator().getOperatorTag() != PhysicalOperatorTag.HASH_PARTITION_MERGE_EXCHANGE)) {
             return false;
         }
         AbstractLogicalOperator op2 = (AbstractLogicalOperator) op1.getInputs().get(0).getValue();
@@ -50,6 +52,12 @@
                 || op2.getPhysicalOperator().getOperatorTag() != PhysicalOperatorTag.SORT_MERGE_EXCHANGE) {
             return false;
         }
+        if (op1.getPhysicalOperator().getOperatorTag() == PhysicalOperatorTag.HASH_PARTITION_MERGE_EXCHANGE) {
+            // if it is a hash_partition_merge_exchange, the sort_merge_exchange can be simply removed
+            op1.getInputs().get(0).setValue(op2.getInputs().get(0).getValue());
+            op1.computeDeliveredPhysicalProperties(context);
+            return true;
+        }
         HashPartitionExchangePOperator hpe = (HashPartitionExchangePOperator) op1.getPhysicalOperator();
         SortMergeExchangePOperator sme = (SortMergeExchangePOperator) op2.getPhysicalOperator();
         List<OrderColumn> ocList = new ArrayList<OrderColumn>();
@@ -60,6 +68,7 @@
                 hpe.getDomain());
         op1.setPhysicalOperator(hpme);
         op1.getInputs().get(0).setValue(op2.getInputs().get(0).getValue());
+        op1.computeDeliveredPhysicalProperties(context);
         return true;
     }
 
diff --git a/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/PullSelectOutOfEqJoin.java b/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/PullSelectOutOfEqJoin.java
index 2a0f6c3..756e0f3 100644
--- a/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/PullSelectOutOfEqJoin.java
+++ b/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/PullSelectOutOfEqJoin.java
@@ -48,8 +48,7 @@
             throws AlgebricksException {
         AbstractLogicalOperator op = (AbstractLogicalOperator) opRef.getValue();
 
-        if (op.getOperatorTag() != LogicalOperatorTag.INNERJOIN
-                && op.getOperatorTag() != LogicalOperatorTag.LEFTOUTERJOIN) {
+        if (op.getOperatorTag() != LogicalOperatorTag.INNERJOIN) {
             return false;
         }
         AbstractBinaryJoinOperator join = (AbstractBinaryJoinOperator) op;
diff --git a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/aggreg/NestedPlansAccumulatingAggregatorFactory.java b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/aggreg/NestedPlansAccumulatingAggregatorFactory.java
index 8f2eaac..09354a5 100644
--- a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/aggreg/NestedPlansAccumulatingAggregatorFactory.java
+++ b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/aggreg/NestedPlansAccumulatingAggregatorFactory.java
@@ -28,11 +28,11 @@
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.FrameTupleAccessor;
+import edu.uci.ics.hyracks.dataflow.std.group.AbstractAccumulatingAggregatorDescriptorFactory;
 import edu.uci.ics.hyracks.dataflow.std.group.AggregateState;
 import edu.uci.ics.hyracks.dataflow.std.group.IAggregatorDescriptor;
-import edu.uci.ics.hyracks.dataflow.std.group.IAggregatorDescriptorFactory;
 
-public class NestedPlansAccumulatingAggregatorFactory implements IAggregatorDescriptorFactory {
+public class NestedPlansAccumulatingAggregatorFactory extends AbstractAccumulatingAggregatorDescriptorFactory {
 
     private static final long serialVersionUID = 1L;
     private AlgebricksPipeline[] subplans;
@@ -95,7 +95,7 @@
             }
 
             @Override
-            public void outputFinalResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
+            public boolean outputFinalResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
                     AggregateState state) throws HyracksDataException {
                 for (int i = 0; i < pipelines.length; i++) {
                     outputWriter.setInputIdx(i);
@@ -114,6 +114,7 @@
                     offset = fieldEnds[i] - start;
                     tupleBuilder.addField(data, start, offset);
                 }
+                return true;
             }
 
             @Override
@@ -127,7 +128,7 @@
             }
 
             @Override
-            public void outputPartialResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
+            public boolean outputPartialResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
                     AggregateState state) throws HyracksDataException {
                 throw new IllegalStateException("this method should not be called");
             }
diff --git a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/aggreg/NestedPlansRunningAggregatorFactory.java b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/aggreg/NestedPlansRunningAggregatorFactory.java
new file mode 100644
index 0000000..8973c75
--- /dev/null
+++ b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/aggreg/NestedPlansRunningAggregatorFactory.java
@@ -0,0 +1,262 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.hyracks.algebricks.runtime.operators.aggreg;
+
+import java.nio.ByteBuffer;
+
+import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
+import edu.uci.ics.hyracks.algebricks.runtime.base.AlgebricksPipeline;
+import edu.uci.ics.hyracks.algebricks.runtime.base.IPushRuntime;
+import edu.uci.ics.hyracks.algebricks.runtime.base.IPushRuntimeFactory;
+import edu.uci.ics.hyracks.algebricks.runtime.operators.std.NestedTupleSourceRuntimeFactory.NestedTupleSourceRuntime;
+import edu.uci.ics.hyracks.api.comm.IFrameTupleAccessor;
+import edu.uci.ics.hyracks.api.comm.IFrameWriter;
+import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
+import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
+import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
+import edu.uci.ics.hyracks.dataflow.common.comm.io.FrameTupleAccessor;
+import edu.uci.ics.hyracks.dataflow.common.comm.io.FrameTupleAppender;
+import edu.uci.ics.hyracks.dataflow.common.comm.util.FrameUtils;
+import edu.uci.ics.hyracks.dataflow.std.group.AggregateState;
+import edu.uci.ics.hyracks.dataflow.std.group.IAggregatorDescriptor;
+import edu.uci.ics.hyracks.dataflow.std.group.IAggregatorDescriptorFactory;
+
+public class NestedPlansRunningAggregatorFactory implements IAggregatorDescriptorFactory {
+
+    private static final long serialVersionUID = 1L;
+    private AlgebricksPipeline[] subplans;
+    private int[] keyFieldIdx;
+    private int[] decorFieldIdx;
+
+    public NestedPlansRunningAggregatorFactory(AlgebricksPipeline[] subplans, int[] keyFieldIdx, int[] decorFieldIdx) {
+        this.subplans = subplans;
+        this.keyFieldIdx = keyFieldIdx;
+        this.decorFieldIdx = decorFieldIdx;
+    }
+
+    /* (non-Javadoc)
+     * @see edu.uci.ics.hyracks.dataflow.std.group.IAggregatorDescriptorFactory#createAggregator(edu.uci.ics.hyracks.api.context.IHyracksTaskContext, edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor, edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor, int[], int[])
+     */
+    @Override
+    public IAggregatorDescriptor createAggregator(final IHyracksTaskContext ctx, RecordDescriptor inRecordDescriptor,
+            RecordDescriptor outRecordDescriptor, int[] keyFields, int[] keyFieldsInPartialResults,
+            final IFrameWriter writer) throws HyracksDataException {
+        final RunningAggregatorOutput outputWriter = new RunningAggregatorOutput(ctx, subplans, keyFieldIdx.length,
+                decorFieldIdx.length, writer);
+        final NestedTupleSourceRuntime[] pipelines = new NestedTupleSourceRuntime[subplans.length];
+        for (int i = 0; i < subplans.length; i++) {
+            try {
+                pipelines[i] = (NestedTupleSourceRuntime) assemblePipeline(subplans[i], outputWriter, ctx);
+            } catch (AlgebricksException e) {
+                throw new HyracksDataException(e);
+            }
+        }
+
+        final ArrayTupleBuilder gbyTb = outputWriter.getGroupByTupleBuilder();
+
+        final ByteBuffer outputFrame = ctx.allocateFrame();
+        final FrameTupleAppender outputAppender = new FrameTupleAppender(ctx.getFrameSize());
+        outputAppender.reset(outputFrame, true);
+
+        return new IAggregatorDescriptor() {
+
+            @Override
+            public void init(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
+                    AggregateState state) throws HyracksDataException {
+
+                for (int i = 0; i < pipelines.length; ++i) {
+                    pipelines[i].open();
+                }
+
+                gbyTb.reset();
+                for (int i = 0; i < keyFieldIdx.length; ++i) {
+                    gbyTb.addField(accessor, tIndex, keyFieldIdx[i]);
+                }
+                for (int i = 0; i < decorFieldIdx.length; ++i) {
+                    gbyTb.addField(accessor, tIndex, decorFieldIdx[i]);
+                }
+
+                // aggregate the first tuple
+                for (int i = 0; i < pipelines.length; i++) {
+                    outputWriter.setInputIdx(i);
+                    pipelines[i].writeTuple(accessor.getBuffer(), tIndex);
+                    pipelines[i].forceFlush();
+                }
+            }
+
+            @Override
+            public void aggregate(IFrameTupleAccessor accessor, int tIndex, IFrameTupleAccessor stateAccessor,
+                    int stateTupleIndex, AggregateState state) throws HyracksDataException {
+                for (int i = 0; i < pipelines.length; i++) {
+                    outputWriter.setInputIdx(i);
+                    pipelines[i].writeTuple(accessor.getBuffer(), tIndex);
+                    pipelines[i].forceFlush();
+                }
+            }
+
+            @Override
+            public boolean outputFinalResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
+                    AggregateState state) throws HyracksDataException {
+                return false;
+            }
+
+            @Override
+            public AggregateState createAggregateStates() {
+                return new AggregateState();
+            }
+
+            @Override
+            public void reset() {
+
+            }
+
+            @Override
+            public boolean outputPartialResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor,
+                    int tIndex, AggregateState state) throws HyracksDataException {
+                throw new IllegalStateException("this method should not be called");
+            }
+
+            @Override
+            public void close() {
+                for (int i = 0; i < pipelines.length; ++i) {
+                    try {
+                        outputWriter.setInputIdx(i);
+                        pipelines[i].close();
+                    } catch (HyracksDataException e) {
+                        throw new IllegalStateException(e);
+                    }
+                }
+            }
+        };
+    }
+
+    private IFrameWriter assemblePipeline(AlgebricksPipeline subplan, IFrameWriter writer, IHyracksTaskContext ctx)
+            throws AlgebricksException, HyracksDataException {
+        // plug the operators
+        IFrameWriter start = writer;
+        IPushRuntimeFactory[] runtimeFactories = subplan.getRuntimeFactories();
+        RecordDescriptor[] recordDescriptors = subplan.getRecordDescriptors();
+        for (int i = runtimeFactories.length - 1; i >= 0; i--) {
+            IPushRuntime newRuntime = runtimeFactories[i].createPushRuntime(ctx);
+            newRuntime.setFrameWriter(0, start, recordDescriptors[i]);
+            if (i > 0) {
+                newRuntime.setInputRecordDescriptor(0, recordDescriptors[i - 1]);
+            } else {
+                // the nts has the same input and output rec. desc.
+                newRuntime.setInputRecordDescriptor(0, recordDescriptors[0]);
+            }
+            start = newRuntime;
+        }
+        return start;
+    }
+
+    private static class RunningAggregatorOutput implements IFrameWriter {
+
+        private FrameTupleAccessor[] tAccess;
+        private RecordDescriptor[] inputRecDesc;
+        private int inputIdx;
+        private ArrayTupleBuilder tb;
+        private ArrayTupleBuilder gbyTb;
+        private AlgebricksPipeline[] subplans;
+        private IFrameWriter outputWriter;
+        private ByteBuffer outputFrame;
+        private FrameTupleAppender outputAppender;
+
+        public RunningAggregatorOutput(IHyracksTaskContext ctx, AlgebricksPipeline[] subplans, int numKeys,
+                int numDecors, IFrameWriter outputWriter) throws HyracksDataException {
+            this.subplans = subplans;
+            this.outputWriter = outputWriter;
+
+            // this.keyFieldIndexes = keyFieldIndexes;
+            int totalAggFields = 0;
+            this.inputRecDesc = new RecordDescriptor[subplans.length];
+            for (int i = 0; i < subplans.length; i++) {
+                RecordDescriptor[] rd = subplans[i].getRecordDescriptors();
+                this.inputRecDesc[i] = rd[rd.length - 1];
+                totalAggFields += subplans[i].getOutputWidth();
+            }
+            tb = new ArrayTupleBuilder(numKeys + numDecors + totalAggFields);
+            gbyTb = new ArrayTupleBuilder(numKeys + numDecors);
+
+            this.tAccess = new FrameTupleAccessor[inputRecDesc.length];
+            for (int i = 0; i < inputRecDesc.length; i++) {
+                tAccess[i] = new FrameTupleAccessor(ctx.getFrameSize(), inputRecDesc[i]);
+            }
+
+            this.outputFrame = ctx.allocateFrame();
+            this.outputAppender = new FrameTupleAppender(ctx.getFrameSize());
+            this.outputAppender.reset(outputFrame, true);
+        }
+
+        @Override
+        public void open() throws HyracksDataException {
+
+        }
+
+        @Override
+        public void nextFrame(ByteBuffer buffer) throws HyracksDataException {
+            int w = subplans[inputIdx].getOutputWidth();
+            IFrameTupleAccessor accessor = tAccess[inputIdx];
+            accessor.reset(buffer);
+            for (int tIndex = 0; tIndex < accessor.getTupleCount(); tIndex++) {
+                tb.reset();
+                byte[] data = gbyTb.getByteArray();
+                int[] fieldEnds = gbyTb.getFieldEndOffsets();
+                int start = 0;
+                int offset = 0;
+                for (int i = 0; i < fieldEnds.length; i++) {
+                    if (i > 0)
+                        start = fieldEnds[i - 1];
+                    offset = fieldEnds[i] - start;
+                    tb.addField(data, start, offset);
+                }
+                for (int f = 0; f < w; f++) {
+                    tb.addField(accessor, tIndex, f);
+                }
+                if (!outputAppender.append(tb.getFieldEndOffsets(), tb.getByteArray(), 0, tb.getSize())) {
+                    FrameUtils.flushFrame(outputFrame, outputWriter);
+                    outputAppender.reset(outputFrame, true);
+                    if (!outputAppender.append(tb.getFieldEndOffsets(), tb.getByteArray(), 0, tb.getSize())) {
+                        throw new HyracksDataException(
+                                "Failed to write a running aggregation result into an empty frame: possibly the size of the result is too large.");
+                    }
+                }
+            }
+        }
+
+        @Override
+        public void close() throws HyracksDataException {
+            if(outputAppender.getTupleCount() > 0){
+                FrameUtils.flushFrame(outputFrame, outputWriter);
+                outputAppender.reset(outputFrame, true);
+            }
+        }
+
+        public void setInputIdx(int inputIdx) {
+            this.inputIdx = inputIdx;
+        }
+
+        public ArrayTupleBuilder getGroupByTupleBuilder() {
+            return gbyTb;
+        }
+
+        @Override
+        public void fail() throws HyracksDataException {
+        }
+
+    }
+
+}
diff --git a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/aggreg/SerializableAggregatorDescriptorFactory.java b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/aggreg/SerializableAggregatorDescriptorFactory.java
index d4161fc..39db3e1 100644
--- a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/aggreg/SerializableAggregatorDescriptorFactory.java
+++ b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/aggreg/SerializableAggregatorDescriptorFactory.java
@@ -25,11 +25,11 @@
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.FrameTupleReference;
+import edu.uci.ics.hyracks.dataflow.std.group.AbstractAccumulatingAggregatorDescriptorFactory;
 import edu.uci.ics.hyracks.dataflow.std.group.AggregateState;
 import edu.uci.ics.hyracks.dataflow.std.group.IAggregatorDescriptor;
-import edu.uci.ics.hyracks.dataflow.std.group.IAggregatorDescriptorFactory;
 
-public class SerializableAggregatorDescriptorFactory implements IAggregatorDescriptorFactory {
+public class SerializableAggregatorDescriptorFactory extends AbstractAccumulatingAggregatorDescriptorFactory {
     private static final long serialVersionUID = 1L;
     private ICopySerializableAggregateFunctionFactory[] aggFactories;
 
@@ -109,7 +109,7 @@
             }
 
             @Override
-            public void outputPartialResult(ArrayTupleBuilder tb, IFrameTupleAccessor accessor, int tIndex,
+            public boolean outputPartialResult(ArrayTupleBuilder tb, IFrameTupleAccessor accessor, int tIndex,
                     AggregateState state) throws HyracksDataException {
                 byte[] data = accessor.getBuffer().array();
                 int startOffset = accessor.getTupleStartOffset(tIndex);
@@ -125,10 +125,11 @@
                         throw new HyracksDataException(e);
                     }
                 }
+                return true;
             }
 
             @Override
-            public void outputFinalResult(ArrayTupleBuilder tb, IFrameTupleAccessor accessor, int tIndex,
+            public boolean outputFinalResult(ArrayTupleBuilder tb, IFrameTupleAccessor accessor, int tIndex,
                     AggregateState state) throws HyracksDataException {
                 byte[] data = accessor.getBuffer().array();
                 int startOffset = accessor.getTupleStartOffset(tIndex);
@@ -144,6 +145,7 @@
                         throw new HyracksDataException(e);
                     }
                 }
+                return true;
             }
 
             @Override
diff --git a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/aggreg/SimpleAlgebricksAccumulatingAggregatorFactory.java b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/aggreg/SimpleAlgebricksAccumulatingAggregatorFactory.java
index 8e472ec..9b638b4 100644
--- a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/aggreg/SimpleAlgebricksAccumulatingAggregatorFactory.java
+++ b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/aggreg/SimpleAlgebricksAccumulatingAggregatorFactory.java
@@ -25,11 +25,11 @@
 import edu.uci.ics.hyracks.data.std.primitive.VoidPointable;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.FrameTupleReference;
+import edu.uci.ics.hyracks.dataflow.std.group.AbstractAccumulatingAggregatorDescriptorFactory;
 import edu.uci.ics.hyracks.dataflow.std.group.AggregateState;
 import edu.uci.ics.hyracks.dataflow.std.group.IAggregatorDescriptor;
-import edu.uci.ics.hyracks.dataflow.std.group.IAggregatorDescriptorFactory;
 
-public class SimpleAlgebricksAccumulatingAggregatorFactory implements IAggregatorDescriptorFactory {
+public class SimpleAlgebricksAccumulatingAggregatorFactory extends AbstractAccumulatingAggregatorDescriptorFactory {
 
     private static final long serialVersionUID = 1L;
     private IAggregateEvaluatorFactory[] aggFactories;
@@ -86,7 +86,7 @@
             }
 
             @Override
-            public void outputFinalResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
+            public boolean outputFinalResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
                     AggregateState state) throws HyracksDataException {
                 IAggregateEvaluator[] agg = (IAggregateEvaluator[]) state.state;
                 for (int i = 0; i < agg.length; i++) {
@@ -97,6 +97,7 @@
                         throw new HyracksDataException(e);
                     }
                 }
+                return true;
             }
 
             @Override
@@ -118,7 +119,7 @@
             }
 
             @Override
-            public void outputPartialResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
+            public boolean outputPartialResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
                     AggregateState state) throws HyracksDataException {
                 throw new IllegalStateException("this method should not be called");
             }
diff --git a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/base/AbstractOneInputOneOutputOneFramePushRuntime.java b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/base/AbstractOneInputOneOutputOneFramePushRuntime.java
index 6c1dd5e..b079c3e 100644
--- a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/base/AbstractOneInputOneOutputOneFramePushRuntime.java
+++ b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/base/AbstractOneInputOneOutputOneFramePushRuntime.java
@@ -51,8 +51,8 @@
             FrameUtils.flushFrame(frame, writer);
             appender.reset(frame, true);
             if (!appender.append(tb.getFieldEndOffsets(), tb.getByteArray(), 0, tb.getSize())) {
-                throw new IllegalStateException(
-                        "Could not write frame (AbstractOneInputOneOutputOneFramePushRuntime.appendToFrameFromTupleBuilder).");
+                throw new HyracksDataException(
+                        "Could not write frame: the size of the tuple is too long to be fit into a single frame. (AbstractOneInputOneOutputOneFramePushRuntime.appendToFrameFromTupleBuilder)");
             }
         }
         if (flushFrame) {
diff --git a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/group/MicroPreClusteredGroupRuntimeFactory.java b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/group/MicroPreClusteredGroupRuntimeFactory.java
index 200e5c5..7ecb288 100644
--- a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/group/MicroPreClusteredGroupRuntimeFactory.java
+++ b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/group/MicroPreClusteredGroupRuntimeFactory.java
@@ -63,8 +63,6 @@
             for (int i = 0; i < comparatorFactories.length; ++i) {
                 comparators[i] = comparatorFactories[i].createBinaryComparator();
             }
-            final IAggregatorDescriptor aggregator = aggregatorFactory.createAggregator(ctx, inRecordDesc,
-                    outRecordDesc, groupFields, groupFields);
             final ByteBuffer copyFrame = ctx.allocateFrame();
             final FrameTupleAccessor copyFrameAccessor = new FrameTupleAccessor(ctx.getFrameSize(), inRecordDesc);
             copyFrameAccessor.reset(copyFrame);
@@ -78,6 +76,8 @@
 
                 @Override
                 public void open() throws HyracksDataException {
+                    IAggregatorDescriptor aggregator = aggregatorFactory.createAggregator(ctx, inRecordDesc,
+                            outRecordDesc, groupFields, groupFields, writer);
                     pgw = new PreclusteredGroupWriter(ctx, groupFields, comparators, aggregator, inRecordDesc,
                             outRecordDesc, writer);
                     pgw.open();
diff --git a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/meta/SubplanRuntimeFactory.java b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/meta/SubplanRuntimeFactory.java
index 0499684..e5bede2 100644
--- a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/meta/SubplanRuntimeFactory.java
+++ b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/meta/SubplanRuntimeFactory.java
@@ -107,7 +107,8 @@
                             FrameUtils.flushFrame(frame, writer);
                             appender.reset(frame, true);
                             if (!appender.appendConcat(tRef.getFrameTupleAccessor(), tRef.getTupleIndex(), ta, t)) {
-                                throw new IllegalStateException("Could not write frame.");
+                                throw new HyracksDataException(
+                                        "Could not write frame: subplan result is larger than the single-frame limit.");
                             }
                         }
                     }
diff --git a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/sort/InMemorySortRuntimeFactory.java b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/sort/InMemorySortRuntimeFactory.java
index b299e78..131eea0 100644
--- a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/sort/InMemorySortRuntimeFactory.java
+++ b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/sort/InMemorySortRuntimeFactory.java
@@ -24,7 +24,7 @@
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputerFactory;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
-import edu.uci.ics.hyracks.dataflow.std.sort.FrameSorter;
+import edu.uci.ics.hyracks.dataflow.std.sort.FrameSorterMergeSort;
 
 public class InMemorySortRuntimeFactory extends AbstractOneInputOneOutputRuntimeFactory {
 
@@ -52,12 +52,12 @@
 
         return new AbstractOneInputOneOutputPushRuntime() {
 
-            FrameSorter frameSorter = null;
+            FrameSorterMergeSort frameSorter = null;
 
             @Override
             public void open() throws HyracksDataException {
                 if (frameSorter == null) {
-                    frameSorter = new FrameSorter(ctx, sortFields, firstKeyNormalizerFactory, comparatorFactories,
+                    frameSorter = new FrameSorterMergeSort(ctx, sortFields, firstKeyNormalizerFactory, comparatorFactories,
                             outputRecordDesc);
                 }
                 frameSorter.reset();
diff --git a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/std/NestedTupleSourceRuntimeFactory.java b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/std/NestedTupleSourceRuntimeFactory.java
index 5486fae..55dbcbb 100644
--- a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/std/NestedTupleSourceRuntimeFactory.java
+++ b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/std/NestedTupleSourceRuntimeFactory.java
@@ -21,6 +21,7 @@
 import edu.uci.ics.hyracks.algebricks.runtime.operators.base.AbstractOneInputOneOutputOneFramePushRuntime;
 import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+import edu.uci.ics.hyracks.dataflow.common.comm.util.FrameUtils;
 
 public class NestedTupleSourceRuntimeFactory implements IPushRuntimeFactory {
 
@@ -64,5 +65,10 @@
         public void fail() throws HyracksDataException {
             writer.fail();
         }
+
+        public void forceFlush() throws HyracksDataException {
+            FrameUtils.flushFrame(frame, writer);
+            appender.reset(frame, true);
+        }
     }
 }
\ No newline at end of file
diff --git a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/std/RunningAggregateRuntimeFactory.java b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/std/RunningAggregateRuntimeFactory.java
index e92724a..600d641 100644
--- a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/std/RunningAggregateRuntimeFactory.java
+++ b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/std/RunningAggregateRuntimeFactory.java
@@ -28,6 +28,7 @@
 import edu.uci.ics.hyracks.data.std.api.IPointable;
 import edu.uci.ics.hyracks.data.std.primitive.VoidPointable;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
+import edu.uci.ics.hyracks.dataflow.common.comm.util.FrameUtils;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.FrameTupleReference;
 
 public class RunningAggregateRuntimeFactory extends AbstractOneInputOneOutputRuntimeFactory {
@@ -89,6 +90,10 @@
 
             @Override
             public void open() throws HyracksDataException {
+                if (!first) {
+                    FrameUtils.flushFrame(frame, writer);
+                    appender.reset(frame, true);
+                }
                 initAccessAppendRef(ctx);
                 if (first) {
                     first = false;
@@ -96,12 +101,18 @@
                     for (int i = 0; i < n; i++) {
                         try {
                             raggs[i] = runningAggregates[i].createRunningAggregateEvaluator();
-                            raggs[i].init();
                         } catch (AlgebricksException ae) {
                             throw new HyracksDataException(ae);
                         }
                     }
                 }
+                for (int i = 0; i < runningAggregates.length; i++) {
+                    try {
+                        raggs[i].init();
+                    } catch (AlgebricksException ae) {
+                        throw new HyracksDataException(ae);
+                    }
+                }
                 writer.open();
             }
 
diff --git a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/std/UnnestRuntimeFactory.java b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/std/UnnestRuntimeFactory.java
index df70437..415e718 100644
--- a/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/std/UnnestRuntimeFactory.java
+++ b/algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/operators/std/UnnestRuntimeFactory.java
@@ -14,11 +14,15 @@
  */
 package edu.uci.ics.hyracks.algebricks.runtime.operators.std;
 
+import java.io.IOException;
 import java.nio.ByteBuffer;
 
 import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
+import edu.uci.ics.hyracks.algebricks.runtime.base.IScalarEvaluator;
+import edu.uci.ics.hyracks.algebricks.runtime.base.IScalarEvaluatorFactory;
 import edu.uci.ics.hyracks.algebricks.runtime.base.IUnnestingEvaluator;
 import edu.uci.ics.hyracks.algebricks.runtime.base.IUnnestingEvaluatorFactory;
+import edu.uci.ics.hyracks.algebricks.runtime.evaluators.ConstantEvaluatorFactory;
 import edu.uci.ics.hyracks.algebricks.runtime.operators.base.AbstractOneInputOneOutputOneFramePushRuntime;
 import edu.uci.ics.hyracks.algebricks.runtime.operators.base.AbstractOneInputOneOutputRuntimeFactory;
 import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
@@ -26,6 +30,7 @@
 import edu.uci.ics.hyracks.data.std.api.IPointable;
 import edu.uci.ics.hyracks.data.std.primitive.VoidPointable;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
+import edu.uci.ics.hyracks.dataflow.common.data.marshalling.IntegerSerializerDeserializer;
 
 public class UnnestRuntimeFactory extends AbstractOneInputOneOutputRuntimeFactory {
 
@@ -36,12 +41,20 @@
     private int outColPos;
     private final boolean outColIsProjected;
 
+    private final boolean hasPositionalVariable;
+    private IScalarEvaluatorFactory posOffsetEvalFactory;
+
     // Each time step() is called on the aggregate, a new value is written in
     // its output. One byte is written before that value and is neglected.
     // By convention, if the aggregate function writes nothing, it means it
     // produced the last value.
 
     public UnnestRuntimeFactory(int outCol, IUnnestingEvaluatorFactory unnestingFactory, int[] projectionList) {
+        this(outCol, unnestingFactory, projectionList, false, null);
+    }
+
+    public UnnestRuntimeFactory(int outCol, IUnnestingEvaluatorFactory unnestingFactory, int[] projectionList,
+            boolean hashPositionalVariable, IScalarEvaluatorFactory posOffsetEvalFactory) {
         super(projectionList);
         this.outCol = outCol;
         this.unnestingFactory = unnestingFactory;
@@ -52,6 +65,11 @@
             }
         }
         outColIsProjected = outColPos >= 0;
+        this.hasPositionalVariable = hashPositionalVariable;
+        this.posOffsetEvalFactory = posOffsetEvalFactory;
+        if (this.posOffsetEvalFactory == null) {
+            this.posOffsetEvalFactory = new ConstantEvaluatorFactory(new byte[5]);
+        }
     }
 
     @Override
@@ -68,6 +86,8 @@
             private IUnnestingEvaluator agg;
             private ArrayTupleBuilder tupleBuilder;
 
+            private IScalarEvaluator offsetEval = posOffsetEvalFactory.createScalarEvaluator(ctx);
+
             @Override
             public void open() throws HyracksDataException {
                 initAccessAppendRef(ctx);
@@ -86,29 +106,55 @@
                 int nTuple = tAccess.getTupleCount();
                 for (int t = 0; t < nTuple; t++) {
                     tRef.reset(tAccess, t);
+
+                    try {
+                        offsetEval.evaluate(tRef, p);
+                    } catch (AlgebricksException e) {
+                        throw new HyracksDataException(e);
+                    }
+
+                    @SuppressWarnings("static-access")
+                    int offset = IntegerSerializerDeserializer.INSTANCE.getInt(p.getByteArray(), p.getStartOffset());
+
                     try {
                         agg.init(tRef);
+                        // assume that when unnesting the tuple, each step() call for each element
+                        // in the tuple will increase the positionIndex, and the positionIndex will
+                        // be reset when a new tuple is to be processed.
+                        int positionIndex = 1;
                         boolean goon = true;
                         do {
                             tupleBuilder.reset();
                             if (!agg.step(p)) {
                                 goon = false;
                             } else {
-                                if (!outColIsProjected) {
+
+                                if (!outColIsProjected && !hasPositionalVariable) {
                                     appendProjectionToFrame(t, projectionList);
                                 } else {
                                     for (int f = 0; f < outColPos; f++) {
                                         tupleBuilder.addField(tAccess, t, f);
                                     }
-                                    tupleBuilder.addField(p.getByteArray(), p.getStartOffset(), p.getLength());
-                                    for (int f = outColPos + 1; f < projectionList.length; f++) {
+                                    if (outColIsProjected) {
+                                        tupleBuilder.addField(p.getByteArray(), p.getStartOffset(), p.getLength());
+                                    } else {
+                                        tupleBuilder.addField(tAccess, t, outColPos);
+                                    }
+                                    for (int f = outColPos + 1; f < (hasPositionalVariable ? projectionList.length - 1
+                                            : projectionList.length); f++) {
                                         tupleBuilder.addField(tAccess, t, f);
                                     }
                                 }
+                                if (hasPositionalVariable) {
+                                    // Write the positional variable as an INT32
+                                    tupleBuilder.getDataOutput().writeByte(3);
+                                    tupleBuilder.getDataOutput().writeInt(offset + positionIndex++);
+                                    tupleBuilder.addFieldEndOffset();
+                                }
                                 appendToFrameFromTupleBuilder(tupleBuilder);
                             }
                         } while (goon);
-                    } catch (AlgebricksException ae) {
+                    } catch (AlgebricksException | IOException ae) {
                         throw new HyracksDataException(ae);
                     }
                 }
diff --git a/hivesterix/hivesterix-dist/src/test/resources/optimizerts/results/q21_suppliers_who_kept_orders_waiting.plan b/hivesterix/hivesterix-dist/src/test/resources/optimizerts/results/q21_suppliers_who_kept_orders_waiting.plan
index a22bf53..e4f2cd6 100644
--- a/hivesterix/hivesterix-dist/src/test/resources/optimizerts/results/q21_suppliers_who_kept_orders_waiting.plan
+++ b/hivesterix/hivesterix-dist/src/test/resources/optimizerts/results/q21_suppliers_who_kept_orders_waiting.plan
@@ -14,7 +14,7 @@
                }
         -- PRE_CLUSTERED_GROUP_BY[$$17]  |PARTITIONED|
           exchange 
-          -- HASH_PARTITION_MERGE_EXCHANGE MERGE:[$$17(ASC)] HASH:[$$17]  |PARTITIONED|
+          -- HASH_PARTITION_MERGE_EXCHANGE MERGE:[$$17(ASC), $$18(ASC)] HASH:[$$17]  |PARTITIONED|
             group by ([$$17 := %0->$$1; $$18 := %0->$$3]) decor ([]) {
                       aggregate [$$20] <- [function-call: hive:max(PARTIAL1), Args:[%0->$$3]]
                       -- AGGREGATE  |LOCAL|
@@ -50,7 +50,7 @@
                }
         -- PRE_CLUSTERED_GROUP_BY[$$17]  |PARTITIONED|
           exchange 
-          -- HASH_PARTITION_MERGE_EXCHANGE MERGE:[$$17(ASC)] HASH:[$$17]  |PARTITIONED|
+          -- HASH_PARTITION_MERGE_EXCHANGE MERGE:[$$17(ASC), $$18(ASC)] HASH:[$$17]  |PARTITIONED|
             group by ([$$17 := %0->$$1; $$18 := %0->$$3]) decor ([]) {
                       aggregate [$$20] <- [function-call: hive:max(PARTIAL1), Args:[%0->$$3]]
                       -- AGGREGATE  |LOCAL|
diff --git a/hyracks/hyracks-api/src/main/java/edu/uci/ics/hyracks/api/context/IHyracksCommonContext.java b/hyracks/hyracks-api/src/main/java/edu/uci/ics/hyracks/api/context/IHyracksCommonContext.java
index c75f9f9..1af32de 100644
--- a/hyracks/hyracks-api/src/main/java/edu/uci/ics/hyracks/api/context/IHyracksCommonContext.java
+++ b/hyracks/hyracks-api/src/main/java/edu/uci/ics/hyracks/api/context/IHyracksCommonContext.java
@@ -25,4 +25,6 @@
     public IIOManager getIOManager();
 
     public ByteBuffer allocateFrame() throws HyracksDataException;
+    
+    public void deallocateFrames(int frameCount);
 }
\ No newline at end of file
diff --git a/hyracks/hyracks-api/src/main/java/edu/uci/ics/hyracks/api/job/IJobSerializerDeserializerContainer.java b/hyracks/hyracks-api/src/main/java/edu/uci/ics/hyracks/api/job/IJobSerializerDeserializerContainer.java
index 0ce2346..57c9133 100644
--- a/hyracks/hyracks-api/src/main/java/edu/uci/ics/hyracks/api/job/IJobSerializerDeserializerContainer.java
+++ b/hyracks/hyracks-api/src/main/java/edu/uci/ics/hyracks/api/job/IJobSerializerDeserializerContainer.java
@@ -25,7 +25,7 @@
      * @param deploymentId
      * @return
      */
-    public IJobSerializerDeserializer getJobSerializerDeerializer(DeploymentId deploymentId);
+    public IJobSerializerDeserializer getJobSerializerDeserializer(DeploymentId deploymentId);
 
     /**
      * Add a deployment with the job serializer deserializer
diff --git a/hyracks/hyracks-api/src/main/java/edu/uci/ics/hyracks/api/job/JobSerializerDeserializerContainer.java b/hyracks/hyracks-api/src/main/java/edu/uci/ics/hyracks/api/job/JobSerializerDeserializerContainer.java
index 35a1e8b..f2d8fff 100644
--- a/hyracks/hyracks-api/src/main/java/edu/uci/ics/hyracks/api/job/JobSerializerDeserializerContainer.java
+++ b/hyracks/hyracks-api/src/main/java/edu/uci/ics/hyracks/api/job/JobSerializerDeserializerContainer.java
@@ -15,18 +15,18 @@
 
 package edu.uci.ics.hyracks.api.job;
 
-import java.util.HashMap;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
 import edu.uci.ics.hyracks.api.deployment.DeploymentId;
 
 public class JobSerializerDeserializerContainer implements IJobSerializerDeserializerContainer {
 
     private IJobSerializerDeserializer defaultJobSerDe = new JobSerializerDeserializer();
-    private Map<DeploymentId, IJobSerializerDeserializer> jobSerializerDeserializerMap = new HashMap<DeploymentId, IJobSerializerDeserializer>();
+    private Map<DeploymentId, IJobSerializerDeserializer> jobSerializerDeserializerMap = new ConcurrentHashMap<DeploymentId, IJobSerializerDeserializer>();
 
     @Override
-    public synchronized IJobSerializerDeserializer getJobSerializerDeerializer(DeploymentId deploymentId) {
+    public synchronized IJobSerializerDeserializer getJobSerializerDeserializer(DeploymentId deploymentId) {
         if (deploymentId == null) {
             return defaultJobSerDe;
         }
@@ -44,4 +44,9 @@
         jobSerializerDeserializerMap.remove(deploymentId);
     }
 
+    @Override
+    public String toString() {
+        return jobSerializerDeserializerMap.toString();
+    }
+
 }
diff --git a/hyracks/hyracks-client/src/main/java/edu/uci/ics/hyracks/client/dataset/DatasetClientContext.java b/hyracks/hyracks-client/src/main/java/edu/uci/ics/hyracks/client/dataset/DatasetClientContext.java
index aa7008f..3ea81ef 100644
--- a/hyracks/hyracks-client/src/main/java/edu/uci/ics/hyracks/client/dataset/DatasetClientContext.java
+++ b/hyracks/hyracks-client/src/main/java/edu/uci/ics/hyracks/client/dataset/DatasetClientContext.java
@@ -41,4 +41,10 @@
         return ByteBuffer.allocate(frameSize);
     }
 
+    @Override
+    public void deallocateFrames(int frameCount) {
+        // TODO Auto-generated method stub
+        
+    }
+
 }
diff --git a/hyracks/hyracks-control/hyracks-control-common/src/main/java/edu/uci/ics/hyracks/control/common/application/ApplicationContext.java b/hyracks/hyracks-control/hyracks-control-common/src/main/java/edu/uci/ics/hyracks/control/common/application/ApplicationContext.java
index 2ca7ccf..828f2fb 100644
--- a/hyracks/hyracks-control/hyracks-control-common/src/main/java/edu/uci/ics/hyracks/control/common/application/ApplicationContext.java
+++ b/hyracks/hyracks-control/hyracks-control-common/src/main/java/edu/uci/ics/hyracks/control/common/application/ApplicationContext.java
@@ -31,7 +31,9 @@
     protected IJobSerializerDeserializerContainer jobSerDeContainer = new JobSerializerDeserializerContainer();
     protected ThreadFactory threadFactory = new ThreadFactory() {
         public Thread newThread(Runnable r) {
-            return new Thread(r);
+            Thread t = new Thread(r);
+            t.setDaemon(true);
+            return t;
         }
     };
 
diff --git a/hyracks/hyracks-control/hyracks-control-common/src/main/java/edu/uci/ics/hyracks/control/common/deployment/ClassLoaderJobSerializerDeserializer.java b/hyracks/hyracks-control/hyracks-control-common/src/main/java/edu/uci/ics/hyracks/control/common/deployment/ClassLoaderJobSerializerDeserializer.java
index 3a35c25..9be3818 100644
--- a/hyracks/hyracks-control/hyracks-control-common/src/main/java/edu/uci/ics/hyracks/control/common/deployment/ClassLoaderJobSerializerDeserializer.java
+++ b/hyracks/hyracks-control/hyracks-control-common/src/main/java/edu/uci/ics/hyracks/control/common/deployment/ClassLoaderJobSerializerDeserializer.java
@@ -31,7 +31,6 @@
  * This is the IJobSerializerDeserializer implementation for jobs with dynamic deployed jars.
  * 
  * @author yingyib
- *
  */
 public class ClassLoaderJobSerializerDeserializer implements IJobSerializerDeserializer {
 
@@ -99,4 +98,9 @@
     public ClassLoader getClassLoader() throws HyracksException {
         return classLoader;
     }
+
+    @Override
+    public String toString() {
+        return classLoader.toString();
+    }
 }
diff --git a/hyracks/hyracks-control/hyracks-control-common/src/main/java/edu/uci/ics/hyracks/control/common/deployment/DeploymentUtils.java b/hyracks/hyracks-control/hyracks-control-common/src/main/java/edu/uci/ics/hyracks/control/common/deployment/DeploymentUtils.java
index 0677e2e..0724a01 100644
--- a/hyracks/hyracks-control/hyracks-control-common/src/main/java/edu/uci/ics/hyracks/control/common/deployment/DeploymentUtils.java
+++ b/hyracks/hyracks-control/hyracks-control-common/src/main/java/edu/uci/ics/hyracks/control/common/deployment/DeploymentUtils.java
@@ -89,7 +89,7 @@
      */
     public static void deploy(DeploymentId deploymentId, List<URL> urls, IJobSerializerDeserializerContainer container,
             ServerContext ctx, boolean isNC) throws HyracksException {
-        IJobSerializerDeserializer jobSerDe = container.getJobSerializerDeerializer(deploymentId);
+        IJobSerializerDeserializer jobSerDe = container.getJobSerializerDeserializer(deploymentId);
         if (jobSerDe == null) {
             jobSerDe = new ClassLoaderJobSerializerDeserializer();
             container.addJobSerializerDeserializer(deploymentId, jobSerDe);
@@ -116,7 +116,7 @@
         try {
             IJobSerializerDeserializerContainer jobSerDeContainer = appCtx.getJobSerializerDeserializerContainer();
             IJobSerializerDeserializer jobSerDe = deploymentId == null ? null : jobSerDeContainer
-                    .getJobSerializerDeerializer(deploymentId);
+                    .getJobSerializerDeserializer(deploymentId);
             Object obj = jobSerDe == null ? JavaSerializationUtils.deserialize(bytes) : jobSerDe.deserialize(bytes);
             return obj;
         } catch (Exception e) {
@@ -138,7 +138,7 @@
         try {
             IJobSerializerDeserializerContainer jobSerDeContainer = appCtx.getJobSerializerDeserializerContainer();
             IJobSerializerDeserializer jobSerDe = deploymentId == null ? null : jobSerDeContainer
-                    .getJobSerializerDeerializer(deploymentId);
+                    .getJobSerializerDeserializer(deploymentId);
             Class<?> cl = jobSerDe == null ? JavaSerializationUtils.loadClass(className) : jobSerDe
                     .loadClass(className);
             return cl;
@@ -160,7 +160,7 @@
         try {
             IJobSerializerDeserializerContainer jobSerDeContainer = appCtx.getJobSerializerDeserializerContainer();
             IJobSerializerDeserializer jobSerDe = deploymentId == null ? null : jobSerDeContainer
-                    .getJobSerializerDeerializer(deploymentId);
+                    .getJobSerializerDeserializer(deploymentId);
             ClassLoader cl = jobSerDe == null ? DeploymentUtils.class.getClassLoader() : jobSerDe.getClassLoader();
             return cl;
         } catch (Exception e) {
diff --git a/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/Task.java b/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/Task.java
index c72ced1..20075ff 100644
--- a/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/Task.java
+++ b/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/Task.java
@@ -115,6 +115,11 @@
     }
 
     @Override
+    public void deallocateFrames(int frameCount) {
+        joblet.deallocateFrames(frameCount);
+    }
+
+    @Override
     public int getFrameSize() {
         return joblet.getFrameSize();
     }
diff --git a/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/resources/memory/MemoryManager.java b/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/resources/memory/MemoryManager.java
index 8add260..4829173 100644
--- a/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/resources/memory/MemoryManager.java
+++ b/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/resources/memory/MemoryManager.java
@@ -26,10 +26,11 @@
 
     @Override
     public boolean allocate(long memory) {
-        if (this.memory.addAndGet(-memory) < 0) {
-            this.memory.addAndGet(memory);
-            return false;
-        }
+        // commented as now the deallocation is not implemented yet.
+        //        if (this.memory.addAndGet(-memory) < 0) {
+        //            this.memory.addAndGet(memory);
+        //            return false;
+        //        }
         return true;
     }
 
diff --git a/hyracks/hyracks-dataflow-hadoop/src/main/java/edu/uci/ics/hyracks/dataflow/hadoop/mapreduce/MapperOperatorDescriptor.java b/hyracks/hyracks-dataflow-hadoop/src/main/java/edu/uci/ics/hyracks/dataflow/hadoop/mapreduce/MapperOperatorDescriptor.java
index 04b91b2..31cd29b 100644
--- a/hyracks/hyracks-dataflow-hadoop/src/main/java/edu/uci/ics/hyracks/dataflow/hadoop/mapreduce/MapperOperatorDescriptor.java
+++ b/hyracks/hyracks-dataflow-hadoop/src/main/java/edu/uci/ics/hyracks/dataflow/hadoop/mapreduce/MapperOperatorDescriptor.java
@@ -43,6 +43,7 @@
 import edu.uci.ics.hyracks.dataflow.common.comm.util.FrameUtils;
 import edu.uci.ics.hyracks.dataflow.std.base.AbstractSingleActivityOperatorDescriptor;
 import edu.uci.ics.hyracks.dataflow.std.base.AbstractUnaryOutputSourceOperatorNodePushable;
+import edu.uci.ics.hyracks.dataflow.std.sort.Algorithm;
 import edu.uci.ics.hyracks.dataflow.std.sort.ExternalSortRunGenerator;
 import edu.uci.ics.hyracks.dataflow.std.sort.ExternalSortRunMerger;
 
@@ -53,8 +54,8 @@
     private final MarshalledWritable<Configuration> config;
     private final IInputSplitProviderFactory factory;
 
-    public MapperOperatorDescriptor(IOperatorDescriptorRegistry spec, int jobId, MarshalledWritable<Configuration> config,
-            IInputSplitProviderFactory factory) throws HyracksDataException {
+    public MapperOperatorDescriptor(IOperatorDescriptorRegistry spec, int jobId,
+            MarshalledWritable<Configuration> config, IInputSplitProviderFactory factory) throws HyracksDataException {
         super(spec, 0, 1);
         this.jobId = jobId;
         this.config = config;
@@ -94,7 +95,7 @@
 
             public void initBlock(int blockId) throws HyracksDataException {
                 runGen = new ExternalSortRunGenerator(ctx, new int[] { 0 }, null, comparatorFactories,
-                        helper.getMapOutputRecordDescriptorWithoutExtraFields(), framesLimit);
+                        helper.getMapOutputRecordDescriptorWithoutExtraFields(), Algorithm.MERGE_SORT, framesLimit);
                 this.blockId = blockId;
             }
 
@@ -114,7 +115,8 @@
                     runGen.nextFrame(frame);
                     fta.reset(frame, true);
                     if (!fta.append(tb.getFieldEndOffsets(), tb.getByteArray(), 0, tb.getSize())) {
-                        throw new HyracksDataException("Record size (" + tb.getSize() + ") larger than frame size (" + frame.capacity() + ")");
+                        throw new HyracksDataException("Record size (" + tb.getSize() + ") larger than frame size ("
+                                + frame.capacity() + ")");
                     }
                 }
             }
@@ -224,7 +226,7 @@
                     comparators[i] = comparatorFactories[i].createBinaryComparator();
                 }
                 ExternalSortRunMerger merger = new ExternalSortRunMerger(ctx, runGen.getFrameSorter(),
-                        runGen.getRuns(), new int[] { 0 }, comparators,
+                        runGen.getRuns(), new int[] { 0 }, comparators, null,
                         helper.getMapOutputRecordDescriptorWithoutExtraFields(), framesLimit, delegatingWriter);
                 merger.process();
             }
diff --git a/hyracks/hyracks-dataflow-hadoop/src/main/java/edu/uci/ics/hyracks/dataflow/hadoop/mapreduce/ShuffleFrameReader.java b/hyracks/hyracks-dataflow-hadoop/src/main/java/edu/uci/ics/hyracks/dataflow/hadoop/mapreduce/ShuffleFrameReader.java
index 30ba3ec..3bb78f9 100644
--- a/hyracks/hyracks-dataflow-hadoop/src/main/java/edu/uci/ics/hyracks/dataflow/hadoop/mapreduce/ShuffleFrameReader.java
+++ b/hyracks/hyracks-dataflow-hadoop/src/main/java/edu/uci/ics/hyracks/dataflow/hadoop/mapreduce/ShuffleFrameReader.java
@@ -108,7 +108,7 @@
             runs.add(rfw.createReader());
         }
         RunFileWriter rfw = new RunFileWriter(outFile, ctx.getIOManager());
-        ExternalSortRunMerger merger = new ExternalSortRunMerger(ctx, null, runs, new int[] { 0 }, comparators,
+        ExternalSortRunMerger merger = new ExternalSortRunMerger(ctx, null, runs, new int[] { 0 }, comparators, null,
                 recordDescriptor, framesLimit, rfw);
         merger.process();
 
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/collectors/SortMergeFrameReader.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/collectors/SortMergeFrameReader.java
index 235b0d0..2dda9cc 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/collectors/SortMergeFrameReader.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/collectors/SortMergeFrameReader.java
@@ -21,6 +21,7 @@
 import edu.uci.ics.hyracks.api.comm.IFrameReader;
 import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparator;
+import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputer;
 import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.dataflow.std.sort.RunMergingFrameReader;
@@ -31,18 +32,21 @@
     private final int nSenders;
     private final int[] sortFields;
     private final IBinaryComparator[] comparators;
+    private final INormalizedKeyComputer nmkComputer;
     private final RecordDescriptor recordDescriptor;
     private final IPartitionBatchManager pbm;
 
     private RunMergingFrameReader merger;
 
     public SortMergeFrameReader(IHyracksTaskContext ctx, int maxConcurrentMerges, int nSenders, int[] sortFields,
-            IBinaryComparator[] comparators, RecordDescriptor recordDescriptor, IPartitionBatchManager pbm) {
+            IBinaryComparator[] comparators, INormalizedKeyComputer nmkComputer, RecordDescriptor recordDescriptor,
+            IPartitionBatchManager pbm) {
         this.ctx = ctx;
         this.maxConcurrentMerges = maxConcurrentMerges;
         this.nSenders = nSenders;
         this.sortFields = sortFields;
         this.comparators = comparators;
+        this.nmkComputer = nmkComputer;
         this.recordDescriptor = recordDescriptor;
         this.pbm = pbm;
     }
@@ -57,7 +61,7 @@
             List<IFrameReader> batch = new ArrayList<IFrameReader>();
             pbm.getNextBatch(batch, nSenders);
             merger = new RunMergingFrameReader(ctx, batch.toArray(new IFrameReader[nSenders]), inFrames, sortFields,
-                    comparators, recordDescriptor);
+                    comparators, nmkComputer, recordDescriptor);
         } else {
             // multi level merge.
             throw new HyracksDataException("Not yet supported");
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/connectors/MToNPartitioningMergingConnectorDescriptor.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/connectors/MToNPartitioningMergingConnectorDescriptor.java
index 32269bd..1cf402b 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/connectors/MToNPartitioningMergingConnectorDescriptor.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/connectors/MToNPartitioningMergingConnectorDescriptor.java
@@ -23,6 +23,8 @@
 import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparator;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
+import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputer;
+import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputerFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.ITuplePartitionComputerFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
@@ -39,19 +41,23 @@
     private final ITuplePartitionComputerFactory tpcf;
     private final int[] sortFields;
     private final IBinaryComparatorFactory[] comparatorFactories;
+    private final INormalizedKeyComputerFactory nkcFactory;
     private final boolean stable;
 
-    public MToNPartitioningMergingConnectorDescriptor(IConnectorDescriptorRegistry spec, ITuplePartitionComputerFactory tpcf,
-            int[] sortFields, IBinaryComparatorFactory[] comparatorFactories) {
-        this(spec, tpcf, sortFields, comparatorFactories, false);
+    public MToNPartitioningMergingConnectorDescriptor(IConnectorDescriptorRegistry spec,
+            ITuplePartitionComputerFactory tpcf, int[] sortFields, IBinaryComparatorFactory[] comparatorFactories,
+            INormalizedKeyComputerFactory nkcFactory) {
+        this(spec, tpcf, sortFields, comparatorFactories, nkcFactory, false);
     }
 
-    public MToNPartitioningMergingConnectorDescriptor(IConnectorDescriptorRegistry spec, ITuplePartitionComputerFactory tpcf,
-            int[] sortFields, IBinaryComparatorFactory[] comparatorFactories, boolean stable) {
+    public MToNPartitioningMergingConnectorDescriptor(IConnectorDescriptorRegistry spec,
+            ITuplePartitionComputerFactory tpcf, int[] sortFields, IBinaryComparatorFactory[] comparatorFactories,
+            INormalizedKeyComputerFactory nkcFactory, boolean stable) {
         super(spec);
         this.tpcf = tpcf;
         this.sortFields = sortFields;
         this.comparatorFactories = comparatorFactories;
+        this.nkcFactory = nkcFactory;
         this.stable = stable;
     }
 
@@ -71,9 +77,10 @@
         for (int i = 0; i < comparatorFactories.length; ++i) {
             comparators[i] = comparatorFactories[i].createBinaryComparator();
         }
+        INormalizedKeyComputer nmkComputer = nkcFactory == null ? null : nkcFactory.createNormalizedKeyComputer();
         IPartitionBatchManager pbm = new NonDeterministicPartitionBatchManager(nProducerPartitions);
         IFrameReader sortMergeFrameReader = new SortMergeFrameReader(ctx, nProducerPartitions, nProducerPartitions,
-                sortFields, comparators, recordDesc, pbm);
+                sortFields, comparators, nmkComputer, recordDesc, pbm);
         BitSet expectedPartitions = new BitSet();
         expectedPartitions.set(0, nProducerPartitions);
         return new PartitionCollector(ctx, getConnectorId(), index, expectedPartitions, sortMergeFrameReader, pbm);
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/AbstractAccumulatingAggregatorDescriptorFactory.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/AbstractAccumulatingAggregatorDescriptorFactory.java
new file mode 100644
index 0000000..48ee410
--- /dev/null
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/AbstractAccumulatingAggregatorDescriptorFactory.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.hyracks.dataflow.std.group;
+
+import edu.uci.ics.hyracks.api.comm.IFrameWriter;
+import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
+import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
+import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+
+public abstract class AbstractAccumulatingAggregatorDescriptorFactory implements IAggregatorDescriptorFactory {
+
+    private static final long serialVersionUID = 1L;
+
+    /* (non-Javadoc)
+     * @see edu.uci.ics.hyracks.dataflow.std.group.IAggregatorDescriptorFactory#createAggregator(edu.uci.ics.hyracks.api.context.IHyracksTaskContext, edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor, edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor, int[], int[], edu.uci.ics.hyracks.api.comm.IFrameWriter)
+     */
+    @Override
+    public IAggregatorDescriptor createAggregator(IHyracksTaskContext ctx, RecordDescriptor inRecordDescriptor,
+            RecordDescriptor outRecordDescriptor, int[] keyFields, int[] keyFieldsInPartialResults, IFrameWriter writer)
+            throws HyracksDataException {
+        return this
+                .createAggregator(ctx, inRecordDescriptor, outRecordDescriptor, keyFields, keyFieldsInPartialResults);
+    }
+
+    abstract protected IAggregatorDescriptor createAggregator(IHyracksTaskContext ctx,
+            RecordDescriptor inRecordDescriptor, RecordDescriptor outRecordDescriptor, int[] keyFields,
+            final int[] keyFieldsInPartialResults) throws HyracksDataException;
+
+}
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/AbstractRunningAggregatorDescriptor.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/AbstractRunningAggregatorDescriptor.java
new file mode 100644
index 0000000..3dcd4c3
--- /dev/null
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/AbstractRunningAggregatorDescriptor.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.hyracks.dataflow.std.group;
+
+import edu.uci.ics.hyracks.api.comm.IFrameTupleAccessor;
+import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
+
+public abstract class AbstractRunningAggregatorDescriptor implements IAggregatorDescriptor {
+
+    /* (non-Javadoc)
+     * @see edu.uci.ics.hyracks.dataflow.std.group.IAggregatorDescriptor#outputPartialResult(edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder, edu.uci.ics.hyracks.api.comm.IFrameTupleAccessor, int, edu.uci.ics.hyracks.dataflow.std.group.AggregateState)
+     */
+    @Override
+    public boolean outputPartialResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
+            AggregateState state) throws HyracksDataException {
+        return false;
+    }
+
+    /* (non-Javadoc)
+     * @see edu.uci.ics.hyracks.dataflow.std.group.IAggregatorDescriptor#outputFinalResult(edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder, edu.uci.ics.hyracks.api.comm.IFrameTupleAccessor, int, edu.uci.ics.hyracks.dataflow.std.group.AggregateState)
+     */
+    @Override
+    public boolean outputFinalResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
+            AggregateState state) throws HyracksDataException {
+        return false;
+    }
+
+}
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/HashSpillableTableFactory.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/HashSpillableTableFactory.java
index ecd5284..df74a93 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/HashSpillableTableFactory.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/HashSpillableTableFactory.java
@@ -38,9 +38,6 @@
 import edu.uci.ics.hyracks.dataflow.std.structures.SerializableHashTable;
 import edu.uci.ics.hyracks.dataflow.std.structures.TuplePointer;
 
-/**
- *
- */
 public class HashSpillableTableFactory implements ISpillableTableFactory {
 
     private static final long serialVersionUID = 1L;
@@ -104,7 +101,7 @@
         }
 
         final IAggregatorDescriptor aggregator = aggregateFactory.createAggregator(ctx, inRecordDescriptor,
-                outRecordDescriptor, keyFields, keyFieldsInPartialResults);
+                outRecordDescriptor, keyFields, keyFieldsInPartialResults, null);
 
         final AggregateState aggregateState = aggregator.createAggregateStates();
 
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/IAggregatorDescriptor.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/IAggregatorDescriptor.java
index afe460c..f9d4cd3 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/IAggregatorDescriptor.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/IAggregatorDescriptor.java
@@ -18,9 +18,6 @@
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
 
-/**
- *
- */
 public interface IAggregatorDescriptor {
 
     /**
@@ -82,9 +79,10 @@
      * @param offset
      * @param state
      *            The aggregation state.
+     * @return TODO
      * @throws HyracksDataException
      */
-    public void outputPartialResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
+    public boolean outputPartialResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
             AggregateState state) throws HyracksDataException;
 
     /**
@@ -97,9 +95,10 @@
      * @param offset
      * @param state
      *            The aggregation state.
+     * @return TODO
      * @throws HyracksDataException
      */
-    public void outputFinalResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
+    public boolean outputFinalResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
             AggregateState state) throws HyracksDataException;
 
     public void close();
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/IAggregatorDescriptorFactory.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/IAggregatorDescriptorFactory.java
index a4c0564..241956b 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/IAggregatorDescriptorFactory.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/IAggregatorDescriptorFactory.java
@@ -16,17 +16,15 @@
 
 import java.io.Serializable;
 
+import edu.uci.ics.hyracks.api.comm.IFrameWriter;
 import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
 import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 
-/**
- *
- */
 public interface IAggregatorDescriptorFactory extends Serializable {
 
     IAggregatorDescriptor createAggregator(IHyracksTaskContext ctx, RecordDescriptor inRecordDescriptor,
-            RecordDescriptor outRecordDescriptor, int[] keyFields, final int[] keyFieldsInPartialResults)
-            throws HyracksDataException;
+            RecordDescriptor outRecordDescriptor, int[] keyFields, final int[] keyFieldsInPartialResults,
+            IFrameWriter writer) throws HyracksDataException;
 
 }
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/aggregators/MultiFieldsAggregatorFactory.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/aggregators/MultiFieldsAggregatorFactory.java
index 239f24f..08b2218 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/aggregators/MultiFieldsAggregatorFactory.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/aggregators/MultiFieldsAggregatorFactory.java
@@ -21,16 +21,14 @@
 import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
+import edu.uci.ics.hyracks.dataflow.std.group.AbstractAccumulatingAggregatorDescriptorFactory;
 import edu.uci.ics.hyracks.dataflow.std.group.AggregateState;
 import edu.uci.ics.hyracks.dataflow.std.group.IAggregatorDescriptor;
 import edu.uci.ics.hyracks.dataflow.std.group.IAggregatorDescriptorFactory;
 import edu.uci.ics.hyracks.dataflow.std.group.IFieldAggregateDescriptor;
 import edu.uci.ics.hyracks.dataflow.std.group.IFieldAggregateDescriptorFactory;
 
-/**
- *
- */
-public class MultiFieldsAggregatorFactory implements IAggregatorDescriptorFactory {
+public class MultiFieldsAggregatorFactory extends AbstractAccumulatingAggregatorDescriptorFactory {
 
     private static final long serialVersionUID = 1L;
     private final IFieldAggregateDescriptorFactory[] aggregatorFactories;
@@ -78,8 +76,8 @@
             }
 
             @Override
-            public void outputPartialResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
-                    AggregateState state) throws HyracksDataException {
+            public boolean outputPartialResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor,
+                    int tIndex, AggregateState state) throws HyracksDataException {
                 DataOutput dos = tupleBuilder.getDataOutput();
 
                 int tupleOffset = accessor.getTupleStartOffset(tIndex);
@@ -90,11 +88,11 @@
                             ((AggregateState[]) state.state)[i]);
                     tupleBuilder.addFieldEndOffset();
                 }
-
+                return true;
             }
 
             @Override
-            public void outputFinalResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
+            public boolean outputFinalResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
                     AggregateState state) throws HyracksDataException {
                 DataOutput dos = tupleBuilder.getDataOutput();
 
@@ -110,6 +108,7 @@
                     }
                     tupleBuilder.addFieldEndOffset();
                 }
+                return true;
             }
 
             @Override
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/external/ExternalGroupMergeOperatorNodePushable.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/external/ExternalGroupMergeOperatorNodePushable.java
index 21b3b60..fdb59a4 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/external/ExternalGroupMergeOperatorNodePushable.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/external/ExternalGroupMergeOperatorNodePushable.java
@@ -25,6 +25,8 @@
 import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparator;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
+import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputer;
+import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputerFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.api.io.FileReference;
@@ -47,6 +49,7 @@
     private final Object stateId;
     private final int[] keyFields;
     private final IBinaryComparator[] comparators;
+    private final INormalizedKeyComputer nmkComputer;
     private final AggregateState aggregateState;
     private final ArrayTupleBuilder tupleBuilder;
     private final int[] storedKeys;
@@ -76,7 +79,7 @@
     private final FrameTupleAccessor outFrameAccessor;
 
     ExternalGroupMergeOperatorNodePushable(IHyracksTaskContext ctx, Object stateId,
-            IBinaryComparatorFactory[] comparatorFactories, int[] keyFields,
+            IBinaryComparatorFactory[] comparatorFactories, INormalizedKeyComputerFactory nmkFactory, int[] keyFields,
             IAggregatorDescriptorFactory mergerFactory, boolean isOutputSorted, int framesLimit,
             RecordDescriptor outRecordDescriptor) throws HyracksDataException {
         this.stateId = stateId;
@@ -85,13 +88,14 @@
         for (int i = 0; i < comparatorFactories.length; ++i) {
             comparators[i] = comparatorFactories[i].createBinaryComparator();
         }
+        this.nmkComputer = nmkFactory == null ? null : nmkFactory.createNormalizedKeyComputer();
         int[] keyFieldsInPartialResults = new int[keyFields.length];
         for (int i = 0; i < keyFieldsInPartialResults.length; i++) {
             keyFieldsInPartialResults[i] = i;
         }
 
         aggregator = mergerFactory.createAggregator(ctx, outRecordDescriptor, outRecordDescriptor, keyFields,
-                keyFieldsInPartialResults);
+                keyFieldsInPartialResults, writer);
         aggregateState = aggregator.createAggregateStates();
 
         storedKeys = new int[keyFields.length];
@@ -181,7 +185,7 @@
             FrameTupleAccessor[] tupleAccessors = new FrameTupleAccessor[inFrames.size()];
             Comparator<ReferenceEntry> comparator = createEntryComparator(comparators);
             ReferencedPriorityQueue topTuples = new ReferencedPriorityQueue(ctx.getFrameSize(), outRecordDescriptor,
-                    runNumber, comparator);
+                    runNumber, comparator, keyFields, nmkComputer);
             /**
              * current tuple index in each run
              */
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/external/ExternalGroupOperatorDescriptor.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/external/ExternalGroupOperatorDescriptor.java
index b914702..9296ffa 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/external/ExternalGroupOperatorDescriptor.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/external/ExternalGroupOperatorDescriptor.java
@@ -130,8 +130,8 @@
                 IRecordDescriptorProvider recordDescProvider, final int partition, int nPartitions)
                 throws HyracksDataException {
             return new ExternalGroupMergeOperatorNodePushable(ctx, new TaskId(new ActivityId(getOperatorId(),
-                    AGGREGATE_ACTIVITY_ID), partition), comparatorFactories, keyFields, mergerFactory, isOutputSorted,
-                    framesLimit, recordDescriptors[0]);
+                    AGGREGATE_ACTIVITY_ID), partition), comparatorFactories, firstNormalizerFactory, keyFields,
+                    mergerFactory, isOutputSorted, framesLimit, recordDescriptors[0]);
         }
 
     }
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/hash/GroupingHashTable.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/hash/GroupingHashTable.java
index f8ba003..3c0eb2b 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/hash/GroupingHashTable.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/hash/GroupingHashTable.java
@@ -121,7 +121,7 @@
         }
 
         this.aggregator = aggregatorFactory.createAggregator(ctx, inRecordDescriptor, outRecordDescriptor, fields,
-                keyFieldsInPartialResults);
+                keyFieldsInPartialResults, null);
 
         this.aggregateStates = new AggregateState[INIT_AGG_STATE_SIZE];
         accumulatorSize = 0;
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/preclustered/PreclusteredGroupOperatorNodePushable.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/preclustered/PreclusteredGroupOperatorNodePushable.java
index 35cb9e1..71af928 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/preclustered/PreclusteredGroupOperatorNodePushable.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/preclustered/PreclusteredGroupOperatorNodePushable.java
@@ -55,7 +55,7 @@
             comparators[i] = comparatorFactories[i].createBinaryComparator();
         }
         final IAggregatorDescriptor aggregator = aggregatorFactory.createAggregator(ctx, inRecordDescriptor,
-                outRecordDescriptor, groupFields, groupFields);
+                outRecordDescriptor, groupFields, groupFields, writer);
         final ByteBuffer copyFrame = ctx.allocateFrame();
         final FrameTupleAccessor copyFrameAccessor = new FrameTupleAccessor(ctx.getFrameSize(), inRecordDescriptor);
         copyFrameAccessor.reset(copyFrame);
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/preclustered/PreclusteredGroupWriter.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/preclustered/PreclusteredGroupWriter.java
index 7773765..ba9ff49 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/preclustered/PreclusteredGroupWriter.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/group/preclustered/PreclusteredGroupWriter.java
@@ -44,6 +44,8 @@
 
     private boolean first;
 
+    private boolean isFailed = false;
+
     public PreclusteredGroupWriter(IHyracksTaskContext ctx, int[] groupFields, IBinaryComparator[] comparators,
             IAggregatorDescriptor aggregator, RecordDescriptor inRecordDesc, RecordDescriptor outRecordDesc,
             IFrameWriter writer) throws HyracksDataException {
@@ -119,9 +121,9 @@
         for (int j = 0; j < groupFields.length; j++) {
             tupleBuilder.addField(lastTupleAccessor, lastTupleIndex, groupFields[j]);
         }
-        aggregator.outputFinalResult(tupleBuilder, lastTupleAccessor, lastTupleIndex, aggregateState);
+        boolean hasOutput = aggregator.outputFinalResult(tupleBuilder, lastTupleAccessor, lastTupleIndex, aggregateState);
 
-        if (!appender.appendSkipEmptyField(tupleBuilder.getFieldEndOffsets(), tupleBuilder.getByteArray(), 0,
+        if (hasOutput && !appender.appendSkipEmptyField(tupleBuilder.getFieldEndOffsets(), tupleBuilder.getByteArray(), 0,
                 tupleBuilder.getSize())) {
             FrameUtils.flushFrame(outFrame, writer);
             appender.reset(outFrame, true);
@@ -149,17 +151,19 @@
 
     @Override
     public void fail() throws HyracksDataException {
+        isFailed = true;
         writer.fail();
     }
 
     @Override
     public void close() throws HyracksDataException {
-        if (!first) {
+        if (!isFailed && !first) {
             writeOutput(copyFrameAccessor, copyFrameAccessor.getTupleCount() - 1);
             if (appender.getTupleCount() > 0) {
                 FrameUtils.flushFrame(outFrame, writer);
             }
         }
+        aggregator.close();
         aggregateState.close();
         writer.close();
     }
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/Algorithm.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/Algorithm.java
new file mode 100644
index 0000000..5c96bd0
--- /dev/null
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/Algorithm.java
@@ -0,0 +1,21 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.hyracks.dataflow.std.sort;
+
+public enum Algorithm {
+    QUICK_SORT,
+    MERGE_SORT
+}
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/ExternalSortOperatorDescriptor.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/ExternalSortOperatorDescriptor.java
index f80a82c..e1315e7 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/ExternalSortOperatorDescriptor.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/ExternalSortOperatorDescriptor.java
@@ -28,6 +28,7 @@
 import edu.uci.ics.hyracks.api.dataflow.TaskId;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparator;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
+import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputer;
 import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputerFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.IRecordDescriptorProvider;
 import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
@@ -51,6 +52,15 @@
     private final IBinaryComparatorFactory[] comparatorFactories;
     private final int framesLimit;
 
+    private Algorithm alg = Algorithm.MERGE_SORT;
+
+    public ExternalSortOperatorDescriptor(IOperatorDescriptorRegistry spec, int framesLimit, int[] sortFields,
+            INormalizedKeyComputerFactory firstKeyNormalizerFactory, IBinaryComparatorFactory[] comparatorFactories,
+            RecordDescriptor recordDescriptor, Algorithm alg) {
+        this(spec, framesLimit, sortFields, firstKeyNormalizerFactory, comparatorFactories, recordDescriptor);
+        this.alg = alg;
+    }
+
     public ExternalSortOperatorDescriptor(IOperatorDescriptorRegistry spec, int framesLimit, int[] sortFields,
             IBinaryComparatorFactory[] comparatorFactories, RecordDescriptor recordDescriptor) {
         this(spec, framesLimit, sortFields, null, comparatorFactories, recordDescriptor);
@@ -86,7 +96,7 @@
 
     public static class SortTaskState extends AbstractStateObject {
         private List<IFrameReader> runs;
-        private FrameSorter frameSorter;
+        private IFrameSorter frameSorter;
 
         public SortTaskState() {
         }
@@ -122,7 +132,7 @@
                 @Override
                 public void open() throws HyracksDataException {
                     runGen = new ExternalSortRunGenerator(ctx, sortFields, firstKeyNormalizerFactory,
-                            comparatorFactories, recordDescriptors[0], framesLimit);
+                            comparatorFactories, recordDescriptors[0], alg, framesLimit);
                     runGen.open();
                 }
 
@@ -166,14 +176,16 @@
                     SortTaskState state = (SortTaskState) ctx.getStateObject(new TaskId(new ActivityId(getOperatorId(),
                             SORT_ACTIVITY_ID), partition));
                     List<IFrameReader> runs = state.runs;
-                    FrameSorter frameSorter = state.frameSorter;
+                    IFrameSorter frameSorter = state.frameSorter;
                     IBinaryComparator[] comparators = new IBinaryComparator[comparatorFactories.length];
                     for (int i = 0; i < comparatorFactories.length; ++i) {
                         comparators[i] = comparatorFactories[i].createBinaryComparator();
                     }
+                    INormalizedKeyComputer nmkComputer = firstKeyNormalizerFactory == null ? null
+                            : firstKeyNormalizerFactory.createNormalizedKeyComputer();
                     int necessaryFrames = Math.min(runs.size() + 2, framesLimit);
                     ExternalSortRunMerger merger = new ExternalSortRunMerger(ctx, frameSorter, runs, sortFields,
-                            comparators, recordDescriptors[0], necessaryFrames, writer);
+                            comparators, nmkComputer, recordDescriptors[0], necessaryFrames, writer);
                     merger.process();
                 }
             };
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/ExternalSortRunGenerator.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/ExternalSortRunGenerator.java
index b149e30..3736fca 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/ExternalSortRunGenerator.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/ExternalSortRunGenerator.java
@@ -30,15 +30,21 @@
 
 public class ExternalSortRunGenerator implements IFrameWriter {
     private final IHyracksTaskContext ctx;
-    private final FrameSorter frameSorter;
+    private final IFrameSorter frameSorter;
     private final List<IFrameReader> runs;
     private final int maxSortFrames;
 
     public ExternalSortRunGenerator(IHyracksTaskContext ctx, int[] sortFields,
             INormalizedKeyComputerFactory firstKeyNormalizerFactory, IBinaryComparatorFactory[] comparatorFactories,
-            RecordDescriptor recordDesc, int framesLimit) throws HyracksDataException {
+            RecordDescriptor recordDesc, Algorithm alg, int framesLimit) throws HyracksDataException {
         this.ctx = ctx;
-        frameSorter = new FrameSorter(ctx, sortFields, firstKeyNormalizerFactory, comparatorFactories, recordDesc);
+        if (alg == Algorithm.MERGE_SORT) {
+            frameSorter = new FrameSorterMergeSort(ctx, sortFields, firstKeyNormalizerFactory, comparatorFactories,
+                    recordDesc);
+        } else {
+            frameSorter = new FrameSorterQuickSort(ctx, sortFields, firstKeyNormalizerFactory, comparatorFactories,
+                    recordDesc);
+        }
         runs = new LinkedList<IFrameReader>();
         maxSortFrames = framesLimit - 1;
     }
@@ -87,7 +93,7 @@
     public void fail() throws HyracksDataException {
     }
 
-    public FrameSorter getFrameSorter() {
+    public IFrameSorter getFrameSorter() {
         return frameSorter;
     }
 
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/ExternalSortRunMerger.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/ExternalSortRunMerger.java
index 510dfd6..eaf4162 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/ExternalSortRunMerger.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/ExternalSortRunMerger.java
@@ -23,6 +23,7 @@
 import edu.uci.ics.hyracks.api.comm.IFrameWriter;
 import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparator;
+import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputer;
 import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.api.io.FileReference;
@@ -59,6 +60,7 @@
     private final List<IFrameReader> runs;
     private final int[] sortFields;
     private final IBinaryComparator[] comparators;
+    private final INormalizedKeyComputer nmkComputer;
     private final RecordDescriptor recordDesc;
     private final int framesLimit;
     private final IFrameWriter writer;
@@ -66,8 +68,8 @@
     private ByteBuffer outFrame;
     private FrameTupleAppender outFrameAppender;
 
-    private FrameSorter frameSorter; // Used in External sort, no replacement
-                                     // selection
+    private IFrameSorter frameSorter; // Used in External sort, no replacement
+                                      // selection
     private FrameTupleAccessor outFrameAccessor; // Used in External sort, with
                                                  // replacement selection
     private final int outputLimit; // Used in External sort, with replacement
@@ -76,14 +78,15 @@
                              // selection and limit on output size
 
     // Constructor for external sort, no replacement selection
-    public ExternalSortRunMerger(IHyracksTaskContext ctx, FrameSorter frameSorter, List<IFrameReader> runs,
-            int[] sortFields, IBinaryComparator[] comparators, RecordDescriptor recordDesc, int framesLimit,
-            IFrameWriter writer) {
+    public ExternalSortRunMerger(IHyracksTaskContext ctx, IFrameSorter frameSorter, List<IFrameReader> runs,
+            int[] sortFields, IBinaryComparator[] comparators, INormalizedKeyComputer nmkComputer,
+            RecordDescriptor recordDesc, int framesLimit, IFrameWriter writer) {
         this.ctx = ctx;
         this.frameSorter = frameSorter;
         this.runs = new LinkedList<IFrameReader>(runs);
         this.sortFields = sortFields;
         this.comparators = comparators;
+        this.nmkComputer = nmkComputer;
         this.recordDesc = recordDesc;
         this.framesLimit = framesLimit;
         this.writer = writer;
@@ -92,11 +95,13 @@
 
     // Constructor for external sort with replacement selection
     public ExternalSortRunMerger(IHyracksTaskContext ctx, int outputLimit, List<IFrameReader> runs, int[] sortFields,
-            IBinaryComparator[] comparators, RecordDescriptor recordDesc, int framesLimit, IFrameWriter writer) {
+            IBinaryComparator[] comparators, INormalizedKeyComputer nmkComputer, RecordDescriptor recordDesc,
+            int framesLimit, IFrameWriter writer) {
         this.ctx = ctx;
         this.runs = new LinkedList<IFrameReader>(runs);
         this.sortFields = sortFields;
         this.comparators = comparators;
+        this.nmkComputer = nmkComputer;
         this.recordDesc = recordDesc;
         this.framesLimit = framesLimit;
         this.writer = writer;
@@ -162,7 +167,7 @@
 
     private void merge(IFrameWriter mergeResultWriter, IFrameReader[] runCursors) throws HyracksDataException {
         RunMergingFrameReader merger = new RunMergingFrameReader(ctx, runCursors, inFrames, sortFields, comparators,
-                recordDesc);
+                nmkComputer, recordDesc);
         merger.open();
         try {
             while (merger.nextFrame(outFrame)) {
@@ -263,7 +268,7 @@
                 runCursors[i] = runs.get(i);
             }
             RunMergingFrameReader merger = new RunMergingFrameReader(ctx, runCursors, inFrames, sortFields,
-                    comparators, recordDesc);
+                    comparators, nmkComputer, recordDesc);
             merger.open();
             try {
                 while (merger.nextFrame(outFrame)) {
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/FrameSorter.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/FrameSorterMergeSort.java
similarity index 97%
rename from hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/FrameSorter.java
rename to hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/FrameSorterMergeSort.java
index a6bb4e2..cc0f1ef 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/FrameSorter.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/FrameSorterMergeSort.java
@@ -31,7 +31,7 @@
 import edu.uci.ics.hyracks.dataflow.common.comm.util.FrameUtils;
 import edu.uci.ics.hyracks.dataflow.common.util.IntSerDeUtils;
 
-public class FrameSorter {
+public class FrameSorterMergeSort implements IFrameSorter {
     private final IHyracksTaskContext ctx;
     private final int[] sortFields;
     private final INormalizedKeyComputer nkc;
@@ -50,7 +50,7 @@
     private int[] tPointersTemp;
     private int tupleCount;
 
-    public FrameSorter(IHyracksTaskContext ctx, int[] sortFields,
+    public FrameSorterMergeSort(IHyracksTaskContext ctx, int[] sortFields,
             INormalizedKeyComputerFactory firstKeyNormalizerFactory, IBinaryComparatorFactory[] comparatorFactories,
             RecordDescriptor recordDescriptor) throws HyracksDataException {
         this.ctx = ctx;
@@ -69,15 +69,18 @@
         dataFrameCount = 0;
     }
 
+    @Override
     public void reset() {
         dataFrameCount = 0;
         tupleCount = 0;
     }
 
+    @Override
     public int getFrameCount() {
         return dataFrameCount;
     }
 
+    @Override
     public void insertFrame(ByteBuffer buffer) throws HyracksDataException {
         ByteBuffer copyFrame;
         if (dataFrameCount == buffers.size()) {
@@ -90,6 +93,7 @@
         ++dataFrameCount;
     }
 
+    @Override
     public void sortFrames() {
         int nBuffers = dataFrameCount;
         tupleCount = 0;
@@ -123,6 +127,7 @@
         }
     }
 
+    @Override
     public void flushFrames(IFrameWriter writer) throws HyracksDataException {
         appender.reset(outFrame, true);
         for (int ptr = 0; ptr < tupleCount; ++ptr) {
@@ -241,6 +246,7 @@
         return 0;
     }
 
+    @Override
     public void close() {
         this.buffers.clear();
     }
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/FrameSorter.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/FrameSorterQuickSort.java
similarity index 71%
copy from hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/FrameSorter.java
copy to hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/FrameSorterQuickSort.java
index a6bb4e2..083f4a7 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/FrameSorter.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/FrameSorterQuickSort.java
@@ -29,9 +29,8 @@
 import edu.uci.ics.hyracks.dataflow.common.comm.io.FrameTupleAccessor;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.FrameTupleAppender;
 import edu.uci.ics.hyracks.dataflow.common.comm.util.FrameUtils;
-import edu.uci.ics.hyracks.dataflow.common.util.IntSerDeUtils;
 
-public class FrameSorter {
+public class FrameSorterQuickSort implements IFrameSorter {
     private final IHyracksTaskContext ctx;
     private final int[] sortFields;
     private final INormalizedKeyComputer nkc;
@@ -47,10 +46,9 @@
 
     private int dataFrameCount;
     private int[] tPointers;
-    private int[] tPointersTemp;
     private int tupleCount;
 
-    public FrameSorter(IHyracksTaskContext ctx, int[] sortFields,
+    public FrameSorterQuickSort(IHyracksTaskContext ctx, int[] sortFields,
             INormalizedKeyComputerFactory firstKeyNormalizerFactory, IBinaryComparatorFactory[] comparatorFactories,
             RecordDescriptor recordDescriptor) throws HyracksDataException {
         this.ctx = ctx;
@@ -69,15 +67,18 @@
         dataFrameCount = 0;
     }
 
+    @Override
     public void reset() {
         dataFrameCount = 0;
         tupleCount = 0;
     }
 
+    @Override
     public int getFrameCount() {
         return dataFrameCount;
     }
 
+    @Override
     public void insertFrame(ByteBuffer buffer) throws HyracksDataException {
         ByteBuffer copyFrame;
         if (dataFrameCount == buffers.size()) {
@@ -90,6 +91,7 @@
         ++dataFrameCount;
     }
 
+    @Override
     public void sortFrames() {
         int nBuffers = dataFrameCount;
         tupleCount = 0;
@@ -118,11 +120,11 @@
             }
         }
         if (tupleCount > 0) {
-            tPointersTemp = new int[tPointers.length];
-            sort(0, tupleCount);
+            sort(tPointers, 0, tupleCount);
         }
     }
 
+    @Override
     public void flushFrames(IFrameWriter writer) throws HyracksDataException {
         appender.reset(outFrame, true);
         for (int ptr = 0; ptr < tupleCount; ++ptr) {
@@ -145,73 +147,75 @@
         }
     }
 
-    private void sort(int offset, int length) {
-        int step = 1;
-        int len = length;
-        int end = offset + len;
-        /** bottom-up merge */
-        while (step < len) {
-            /** merge */
-            for (int i = offset; i < end; i += 2 * step) {
-                int next = i + step;
-                if (next < end) {
-                    merge(i, next, step, Math.min(step, end - next));
-                } else {
-                    System.arraycopy(tPointers, i * 4, tPointersTemp, i * 4, (end - i) * 4);
+    private void sort(int[] tPointers, int offset, int length) {
+        int m = offset + (length >> 1);
+        int mi = tPointers[m * 4];
+        int mj = tPointers[m * 4 + 1];
+        int mv = tPointers[m * 4 + 3];
+
+        int a = offset;
+        int b = a;
+        int c = offset + length - 1;
+        int d = c;
+        while (true) {
+            while (b <= c) {
+                int cmp = compare(tPointers, b, mi, mj, mv);
+                if (cmp > 0) {
+                    break;
                 }
+                if (cmp == 0) {
+                    swap(tPointers, a++, b);
+                }
+                ++b;
             }
-            /** prepare next phase merge */
-            step *= 2;
-            int[] tmp = tPointersTemp;
-            tPointersTemp = tPointers;
-            tPointers = tmp;
-        }
-    }
-
-    /** Merge two subarrays into one */
-    private void merge(int start1, int start2, int len1, int len2) {
-        int targetPos = start1;
-        int pos1 = start1;
-        int pos2 = start2;
-        int end1 = start1 + len1 - 1;
-        int end2 = start2 + len2 - 1;
-        while (pos1 <= end1 && pos2 <= end2) {
-            int cmp = compare(pos1, pos2);
-            if (cmp <= 0) {
-                copy(pos1, targetPos);
-                pos1++;
-            } else {
-                copy(pos2, targetPos);
-                pos2++;
+            while (c >= b) {
+                int cmp = compare(tPointers, c, mi, mj, mv);
+                if (cmp < 0) {
+                    break;
+                }
+                if (cmp == 0) {
+                    swap(tPointers, c, d--);
+                }
+                --c;
             }
-            targetPos++;
+            if (b > c)
+                break;
+            swap(tPointers, b++, c--);
         }
-        if (pos1 <= end1) {
-            int rest = end1 - pos1 + 1;
-            System.arraycopy(tPointers, pos1 * 4, tPointersTemp, targetPos * 4, rest * 4);
+
+        int s;
+        int n = offset + length;
+        s = Math.min(a - offset, b - a);
+        vecswap(tPointers, offset, b - s, s);
+        s = Math.min(d - c, n - d - 1);
+        vecswap(tPointers, b, n - s, s);
+
+        if ((s = b - a) > 1) {
+            sort(tPointers, offset, s);
         }
-        if (pos2 <= end2) {
-            int rest = end2 - pos2 + 1;
-            System.arraycopy(tPointers, pos2 * 4, tPointersTemp, targetPos * 4, rest * 4);
+        if ((s = d - c) > 1) {
+            sort(tPointers, n - s, s);
         }
     }
 
-    private void copy(int src, int dest) {
-        tPointersTemp[dest * 4] = tPointers[src * 4];
-        tPointersTemp[dest * 4 + 1] = tPointers[src * 4 + 1];
-        tPointersTemp[dest * 4 + 2] = tPointers[src * 4 + 2];
-        tPointersTemp[dest * 4 + 3] = tPointers[src * 4 + 3];
+    private void swap(int x[], int a, int b) {
+        for (int i = 0; i < 4; ++i) {
+            int t = x[a * 4 + i];
+            x[a * 4 + i] = x[b * 4 + i];
+            x[b * 4 + i] = t;
+        }
     }
 
-    private int compare(int tp1, int tp2) {
+    private void vecswap(int x[], int a, int b, int n) {
+        for (int i = 0; i < n; i++, a++, b++) {
+            swap(x, a, b);
+        }
+    }
+
+    private int compare(int[] tPointers, int tp1, int tp2i, int tp2j, int tp2v) {
         int i1 = tPointers[tp1 * 4];
         int j1 = tPointers[tp1 * 4 + 1];
         int v1 = tPointers[tp1 * 4 + 3];
-
-        int tp2i = tPointers[tp2 * 4];
-        int tp2j = tPointers[tp2 * 4 + 1];
-        int tp2v = tPointers[tp2 * 4 + 3];
-
         if (v1 != tp2v) {
             return ((((long) v1) & 0xffffffffL) < (((long) tp2v) & 0xffffffffL)) ? -1 : 1;
         }
@@ -225,12 +229,12 @@
         fta2.reset(buf2);
         for (int f = 0; f < comparators.length; ++f) {
             int fIdx = sortFields[f];
-            int f1Start = fIdx == 0 ? 0 : IntSerDeUtils.getInt(buf1.array(), j1 + (fIdx - 1) * 4);
-            int f1End = IntSerDeUtils.getInt(buf1.array(), j1 + fIdx * 4);
+            int f1Start = fIdx == 0 ? 0 : buf1.getInt(j1 + (fIdx - 1) * 4);
+            int f1End = buf1.getInt(j1 + fIdx * 4);
             int s1 = j1 + fta1.getFieldSlotsLength() + f1Start;
             int l1 = f1End - f1Start;
-            int f2Start = fIdx == 0 ? 0 : IntSerDeUtils.getInt(buf2.array(), j2 + (fIdx - 1) * 4);
-            int f2End = IntSerDeUtils.getInt(buf2.array(), j2 + fIdx * 4);
+            int f2Start = fIdx == 0 ? 0 : buf2.getInt(j2 + (fIdx - 1) * 4);
+            int f2End = buf2.getInt(j2 + fIdx * 4);
             int s2 = j2 + fta2.getFieldSlotsLength() + f2Start;
             int l2 = f2End - f2Start;
             int c = comparators[f].compare(b1, s1, l1, b2, s2, l2);
@@ -241,7 +245,8 @@
         return 0;
     }
 
+    @Override
     public void close() {
         this.buffers.clear();
     }
-}
+}
\ No newline at end of file
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/IFrameSorter.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/IFrameSorter.java
new file mode 100644
index 0000000..6778852
--- /dev/null
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/IFrameSorter.java
@@ -0,0 +1,37 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.hyracks.dataflow.std.sort;
+
+import java.nio.ByteBuffer;
+
+import edu.uci.ics.hyracks.api.comm.IFrameWriter;
+import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+
+public interface IFrameSorter {
+
+    public void reset();
+
+    public int getFrameCount();
+
+    public void insertFrame(ByteBuffer buffer) throws HyracksDataException;
+
+    public void sortFrames();
+
+    public void flushFrames(IFrameWriter writer) throws HyracksDataException;
+
+    public void close();
+
+}
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/InMemorySortOperatorDescriptor.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/InMemorySortOperatorDescriptor.java
index 04c82af..6fa21b5 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/InMemorySortOperatorDescriptor.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/InMemorySortOperatorDescriptor.java
@@ -77,7 +77,7 @@
     }
 
     public static class SortTaskState extends AbstractStateObject {
-        private FrameSorter frameSorter;
+        private FrameSorterMergeSort frameSorter;
 
         public SortTaskState() {
         }
@@ -111,7 +111,7 @@
                 @Override
                 public void open() throws HyracksDataException {
                     state = new SortTaskState(ctx.getJobletContext().getJobId(), new TaskId(getActivityId(), partition));
-                    state.frameSorter = new FrameSorter(ctx, sortFields, firstKeyNormalizerFactory,
+                    state.frameSorter = new FrameSorterMergeSort(ctx, sortFields, firstKeyNormalizerFactory,
                             comparatorFactories, recordDescriptors[0]);
                     state.frameSorter.reset();
                 }
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/OptimizedExternalSortOperatorDescriptor.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/OptimizedExternalSortOperatorDescriptor.java
index bff2e21..ef1ae88 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/OptimizedExternalSortOperatorDescriptor.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/OptimizedExternalSortOperatorDescriptor.java
@@ -28,6 +28,7 @@
 import edu.uci.ics.hyracks.api.dataflow.TaskId;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparator;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
+import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputer;
 import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputerFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.IRecordDescriptorProvider;
 import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
@@ -201,9 +202,11 @@
                         comparators[i] = comparatorFactories[i].createBinaryComparator();
                     }
 
+                    INormalizedKeyComputer nmkComputer = firstKeyNormalizerFactory == null ? null
+                            : firstKeyNormalizerFactory.createNormalizedKeyComputer();
                     int necessaryFrames = Math.min(runs.size() + 2, memSize);
                     ExternalSortRunMerger merger = new ExternalSortRunMerger(ctx, outputLimit, runs, sortFields,
-                            comparators, recordDescriptors[0], necessaryFrames, writer);
+                            comparators, nmkComputer, recordDescriptors[0], necessaryFrames, writer);
 
                     merger.processWithReplacementSelection();
 
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/RunMergingFrameReader.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/RunMergingFrameReader.java
index 16b3c12..00fbe9b 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/RunMergingFrameReader.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/sort/RunMergingFrameReader.java
@@ -22,6 +22,7 @@
 import edu.uci.ics.hyracks.api.comm.IFrameTupleAccessor;
 import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparator;
+import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputer;
 import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.FrameTupleAccessor;
@@ -35,6 +36,7 @@
     private final List<ByteBuffer> inFrames;
     private final int[] sortFields;
     private final IBinaryComparator[] comparators;
+    private final INormalizedKeyComputer nmkComputer;
     private final RecordDescriptor recordDesc;
     private final FrameTupleAppender outFrameAppender;
     private ReferencedPriorityQueue topTuples;
@@ -42,12 +44,14 @@
     private FrameTupleAccessor[] tupleAccessors;
 
     public RunMergingFrameReader(IHyracksTaskContext ctx, IFrameReader[] runCursors, List<ByteBuffer> inFrames,
-            int[] sortFields, IBinaryComparator[] comparators, RecordDescriptor recordDesc) {
+            int[] sortFields, IBinaryComparator[] comparators, INormalizedKeyComputer nmkComputer,
+            RecordDescriptor recordDesc) {
         this.ctx = ctx;
         this.runCursors = runCursors;
         this.inFrames = inFrames;
         this.sortFields = sortFields;
         this.comparators = comparators;
+        this.nmkComputer = nmkComputer;
         this.recordDesc = recordDesc;
         outFrameAppender = new FrameTupleAppender(ctx.getFrameSize());
     }
@@ -56,7 +60,8 @@
     public void open() throws HyracksDataException {
         tupleAccessors = new FrameTupleAccessor[runCursors.length];
         Comparator<ReferenceEntry> comparator = createEntryComparator(comparators);
-        topTuples = new ReferencedPriorityQueue(ctx.getFrameSize(), recordDesc, runCursors.length, comparator);
+        topTuples = new ReferencedPriorityQueue(ctx.getFrameSize(), recordDesc, runCursors.length, comparator,
+                sortFields, nmkComputer);
         tupleIndexes = new int[runCursors.length];
         for (int i = 0; i < runCursors.length; i++) {
             tupleIndexes[i] = 0;
@@ -143,21 +148,25 @@
     private Comparator<ReferenceEntry> createEntryComparator(final IBinaryComparator[] comparators) {
         return new Comparator<ReferenceEntry>() {
             public int compare(ReferenceEntry tp1, ReferenceEntry tp2) {
+                int nmk1 = tp1.getNormalizedKey();
+                int nmk2 = tp1.getNormalizedKey();
+                if (nmk1 > nmk2) {
+                    return 1;
+                }
+                if (nmk1 < nmk2) {
+                    return -1;
+                }
+
                 FrameTupleAccessor fta1 = (FrameTupleAccessor) tp1.getAccessor();
                 FrameTupleAccessor fta2 = (FrameTupleAccessor) tp2.getAccessor();
-                int j1 = tp1.getTupleIndex();
-                int j2 = tp2.getTupleIndex();
                 byte[] b1 = fta1.getBuffer().array();
                 byte[] b2 = fta2.getBuffer().array();
+                int[] tPointers1 = tp1.getTPointers();
+                int[] tPointers2 = tp2.getTPointers();
+
                 for (int f = 0; f < sortFields.length; ++f) {
-                    int fIdx = sortFields[f];
-                    int s1 = fta1.getTupleStartOffset(j1) + fta1.getFieldSlotsLength()
-                            + fta1.getFieldStartOffset(j1, fIdx);
-                    int l1 = fta1.getFieldEndOffset(j1, fIdx) - fta1.getFieldStartOffset(j1, fIdx);
-                    int s2 = fta2.getTupleStartOffset(j2) + fta2.getFieldSlotsLength()
-                            + fta2.getFieldStartOffset(j2, fIdx);
-                    int l2 = fta2.getFieldEndOffset(j2, fIdx) - fta2.getFieldStartOffset(j2, fIdx);
-                    int c = comparators[f].compare(b1, s1, l1, b2, s2, l2);
+                    int c = comparators[f].compare(b1, tPointers1[2 * f + 1], tPointers1[2 * f + 2], b2,
+                            tPointers2[2 * f + 1], tPointers2[2 * f + 2]);
                     if (c != 0) {
                         return c;
                     }
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/util/ReferenceEntry.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/util/ReferenceEntry.java
index c1efa91..c06b50c 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/util/ReferenceEntry.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/util/ReferenceEntry.java
@@ -14,18 +14,24 @@
  */
 package edu.uci.ics.hyracks.dataflow.std.util;
 
+import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputer;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.FrameTupleAccessor;
 
 public class ReferenceEntry {
     private final int runid;
     private FrameTupleAccessor acccessor;
     private int tupleIndex;
+    private int[] tPointers;
 
-    public ReferenceEntry(int runid, FrameTupleAccessor fta, int tupleIndex) {
+    public ReferenceEntry(int runid, FrameTupleAccessor fta, int tupleIndex, int[] keyFields,
+            INormalizedKeyComputer nmkComputer) {
         super();
         this.runid = runid;
         this.acccessor = fta;
-        this.tupleIndex = tupleIndex;
+        this.tPointers = new int[1 + 2 * keyFields.length];
+        if (fta != null) {
+            initTPointer(fta, tupleIndex, keyFields, nmkComputer);
+        }
     }
 
     public int getRunid() {
@@ -40,11 +46,38 @@
         this.acccessor = fta;
     }
 
+    public int[] getTPointers() {
+        return tPointers;
+    }
+
     public int getTupleIndex() {
         return tupleIndex;
     }
 
-    public void setTupleIndex(int tupleIndex) {
+    public int getNormalizedKey() {
+        return tPointers[0];
+    }
+
+    public void setTupleIndex(int tupleIndex, int[] keyFields, INormalizedKeyComputer nmkComputer) {
+        initTPointer(acccessor, tupleIndex, keyFields, nmkComputer);
+    }
+
+    private void initTPointer(FrameTupleAccessor fta, int tupleIndex, int[] keyFields,
+            INormalizedKeyComputer nmkComputer) {
         this.tupleIndex = tupleIndex;
+        byte[] b1 = fta.getBuffer().array();
+        for (int f = 0; f < keyFields.length; ++f) {
+            int fIdx = keyFields[f];
+            tPointers[2 * f + 1] = fta.getTupleStartOffset(tupleIndex) + fta.getFieldSlotsLength()
+                    + fta.getFieldStartOffset(tupleIndex, fIdx);
+            tPointers[2 * f + 2] = fta.getFieldEndOffset(tupleIndex, fIdx) - fta.getFieldStartOffset(tupleIndex, fIdx);
+            if (f == 0) {
+                if (nmkComputer != null) {
+                    tPointers[0] = nmkComputer.normalize(b1, tPointers[1], tPointers[2]);
+                } else {
+                    tPointers[0] = 0;
+                }
+            }
+        }
     }
 }
\ No newline at end of file
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/util/ReferencedPriorityQueue.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/util/ReferencedPriorityQueue.java
index 7767ace..225f583 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/util/ReferencedPriorityQueue.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/util/ReferencedPriorityQueue.java
@@ -18,6 +18,7 @@
 import java.util.BitSet;
 import java.util.Comparator;
 
+import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputer;
 import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.FrameTupleAccessor;
 
@@ -30,21 +31,25 @@
     private int nItems;
 
     private final Comparator<ReferenceEntry> comparator;
+    private final INormalizedKeyComputer nmkComputer;
+    private final int[] keyFields;
 
     public ReferencedPriorityQueue(int frameSize, RecordDescriptor recordDescriptor, int initSize,
-            Comparator<ReferenceEntry> comparator) {
+            Comparator<ReferenceEntry> comparator, int[] keyFields, INormalizedKeyComputer nmkComputer) {
         this.frameSize = frameSize;
         this.recordDescriptor = recordDescriptor;
         if (initSize < 1)
             throw new IllegalArgumentException();
         this.comparator = comparator;
+        this.nmkComputer = nmkComputer;
+        this.keyFields = keyFields;
         nItems = initSize;
         size = (initSize + 1) & 0xfffffffe;
         entries = new ReferenceEntry[size];
         runAvail = new BitSet(size);
         runAvail.set(0, initSize, true);
         for (int i = 0; i < size; i++) {
-            entries[i] = new ReferenceEntry(i, null, -1);
+            entries[i] = new ReferenceEntry(i, null, -1, keyFields, nmkComputer);
         }
     }
 
@@ -71,7 +76,7 @@
             entry.setAccessor(new FrameTupleAccessor(frameSize, recordDescriptor));
         }
         entry.getAccessor().reset(fta.getBuffer());
-        entry.setTupleIndex(tIndex);
+        entry.setTupleIndex(tIndex, keyFields, nmkComputer);
 
         add(entry);
         return entry.getRunid();
diff --git a/hyracks/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/integration/OptimizedSortMergeTest.java b/hyracks/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/integration/OptimizedSortMergeTest.java
index 380ba29..a2ef99a 100644
--- a/hyracks/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/integration/OptimizedSortMergeTest.java
+++ b/hyracks/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/integration/OptimizedSortMergeTest.java
@@ -31,6 +31,7 @@
 import edu.uci.ics.hyracks.data.std.accessors.PointableBinaryHashFunctionFactory;
 import edu.uci.ics.hyracks.data.std.primitive.UTF8StringPointable;
 import edu.uci.ics.hyracks.dataflow.common.data.marshalling.UTF8StringSerializerDeserializer;
+import edu.uci.ics.hyracks.dataflow.common.data.normalizers.UTF8StringNormalizedKeyComputerFactory;
 import edu.uci.ics.hyracks.dataflow.common.data.parsers.IValueParserFactory;
 import edu.uci.ics.hyracks.dataflow.common.data.parsers.UTF8StringParserFactory;
 import edu.uci.ics.hyracks.dataflow.common.data.partition.FieldHashPartitionComputerFactory;
@@ -93,8 +94,8 @@
                         PointableBinaryHashFunctionFactory.of(UTF8StringPointable.FACTORY) }), new int[] { 1, 0 },
                         new IBinaryComparatorFactory[] {
                                 PointableBinaryComparatorFactory.of(UTF8StringPointable.FACTORY),
-                                PointableBinaryComparatorFactory.of(UTF8StringPointable.FACTORY) }), sorter, 0,
-                printer, 0);
+                                PointableBinaryComparatorFactory.of(UTF8StringPointable.FACTORY) },
+                        new UTF8StringNormalizedKeyComputerFactory()), sorter, 0, printer, 0);
 
         runTest(spec);
     }
@@ -148,8 +149,8 @@
                         PointableBinaryHashFunctionFactory.of(UTF8StringPointable.FACTORY) }), new int[] { 1, 0 },
                         new IBinaryComparatorFactory[] {
                                 PointableBinaryComparatorFactory.of(UTF8StringPointable.FACTORY),
-                                PointableBinaryComparatorFactory.of(UTF8StringPointable.FACTORY) }), sorter, 0, filter,
-                0);
+                                PointableBinaryComparatorFactory.of(UTF8StringPointable.FACTORY) },
+                        new UTF8StringNormalizedKeyComputerFactory()), sorter, 0, filter, 0);
 
         spec.connect(new OneToOneConnectorDescriptor(spec), filter, 0, printer, 0);
 
diff --git a/hyracks/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/integration/SortMergeTest.java b/hyracks/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/integration/SortMergeTest.java
index 48db176..faa55e8 100644
--- a/hyracks/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/integration/SortMergeTest.java
+++ b/hyracks/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/integration/SortMergeTest.java
@@ -31,6 +31,7 @@
 import edu.uci.ics.hyracks.data.std.accessors.PointableBinaryHashFunctionFactory;
 import edu.uci.ics.hyracks.data.std.primitive.UTF8StringPointable;
 import edu.uci.ics.hyracks.dataflow.common.data.marshalling.UTF8StringSerializerDeserializer;
+import edu.uci.ics.hyracks.dataflow.common.data.normalizers.UTF8StringNormalizedKeyComputerFactory;
 import edu.uci.ics.hyracks.dataflow.common.data.parsers.IValueParserFactory;
 import edu.uci.ics.hyracks.dataflow.common.data.parsers.UTF8StringParserFactory;
 import edu.uci.ics.hyracks.dataflow.common.data.partition.FieldHashPartitionComputerFactory;
@@ -89,7 +90,8 @@
                         new int[] { 1 }, new IBinaryHashFunctionFactory[] { PointableBinaryHashFunctionFactory
                                 .of(UTF8StringPointable.FACTORY) }), new int[] { 1 },
                         new IBinaryComparatorFactory[] { PointableBinaryComparatorFactory
-                                .of(UTF8StringPointable.FACTORY) }), sorter, 0, printer, 0);
+                                .of(UTF8StringPointable.FACTORY) }, new UTF8StringNormalizedKeyComputerFactory()),
+                sorter, 0, printer, 0);
 
         runTest(spec);
     }
@@ -138,8 +140,8 @@
                         PointableBinaryHashFunctionFactory.of(UTF8StringPointable.FACTORY) }), new int[] { 1, 0 },
                         new IBinaryComparatorFactory[] {
                                 PointableBinaryComparatorFactory.of(UTF8StringPointable.FACTORY),
-                                PointableBinaryComparatorFactory.of(UTF8StringPointable.FACTORY) }), sorter, 0,
-                printer, 0);
+                                PointableBinaryComparatorFactory.of(UTF8StringPointable.FACTORY) },
+                        new UTF8StringNormalizedKeyComputerFactory()), sorter, 0, printer, 0);
 
         runTest(spec);
     }
diff --git a/hyracks/hyracks-hdfs/hyracks-hdfs-core/src/test/java/edu/uci/ics/hyracks/hdfs/dataflow/DataflowTest.java b/hyracks/hyracks-hdfs/hyracks-hdfs-core/src/test/java/edu/uci/ics/hyracks/hdfs/dataflow/DataflowTest.java
index c61c15b..61c5a1c 100644
--- a/hyracks/hyracks-hdfs/hyracks-hdfs-core/src/test/java/edu/uci/ics/hyracks/hdfs/dataflow/DataflowTest.java
+++ b/hyracks/hyracks-hdfs/hyracks-hdfs-core/src/test/java/edu/uci/ics/hyracks/hdfs/dataflow/DataflowTest.java
@@ -156,8 +156,8 @@
         jobSpec.connect(new OneToOneConnectorDescriptor(jobSpec), readOperator, 0, sortOperator, 0);
         jobSpec.connect(new MToNPartitioningMergingConnectorDescriptor(jobSpec, new FieldHashPartitionComputerFactory(
                 new int[] { 0 }, new IBinaryHashFunctionFactory[] { RawBinaryHashFunctionFactory.INSTANCE }),
-                new int[] { 0 }, new IBinaryComparatorFactory[] { RawBinaryComparatorFactory.INSTANCE }), sortOperator,
-                0, writeOperator, 0);
+                new int[] { 0 }, new IBinaryComparatorFactory[] { RawBinaryComparatorFactory.INSTANCE }, null),
+                sortOperator, 0, writeOperator, 0);
         jobSpec.addRoot(writeOperator);
 
         IHyracksClientConnection client = new HyracksConnection(HyracksUtils.CC_HOST,
diff --git a/hyracks/hyracks-hdfs/hyracks-hdfs-core/src/test/java/edu/uci/ics/hyracks/hdfs2/dataflow/DataflowTest.java b/hyracks/hyracks-hdfs/hyracks-hdfs-core/src/test/java/edu/uci/ics/hyracks/hdfs2/dataflow/DataflowTest.java
index 3e43fb1..baa4dc7 100644
--- a/hyracks/hyracks-hdfs/hyracks-hdfs-core/src/test/java/edu/uci/ics/hyracks/hdfs2/dataflow/DataflowTest.java
+++ b/hyracks/hyracks-hdfs/hyracks-hdfs-core/src/test/java/edu/uci/ics/hyracks/hdfs2/dataflow/DataflowTest.java
@@ -163,8 +163,8 @@
         jobSpec.connect(new OneToOneConnectorDescriptor(jobSpec), readOperator, 0, sortOperator, 0);
         jobSpec.connect(new MToNPartitioningMergingConnectorDescriptor(jobSpec, new FieldHashPartitionComputerFactory(
                 new int[] { 0 }, new IBinaryHashFunctionFactory[] { RawBinaryHashFunctionFactory.INSTANCE }),
-                new int[] { 0 }, new IBinaryComparatorFactory[] { RawBinaryComparatorFactory.INSTANCE }), sortOperator,
-                0, writeOperator, 0);
+                new int[] { 0 }, new IBinaryComparatorFactory[] { RawBinaryComparatorFactory.INSTANCE }, null),
+                sortOperator, 0, writeOperator, 0);
         jobSpec.addRoot(writeOperator);
 
         IHyracksClientConnection client = new HyracksConnection(HyracksUtils.CC_HOST,
diff --git a/hyracks/hyracks-storage-am-bloomfilter/src/main/java/edu/uci/ics/hyracks/storage/am/bloomfilter/impls/BloomFilter.java b/hyracks/hyracks-storage-am-bloomfilter/src/main/java/edu/uci/ics/hyracks/storage/am/bloomfilter/impls/BloomFilter.java
index fe25db8..19200ee 100644
--- a/hyracks/hyracks-storage-am-bloomfilter/src/main/java/edu/uci/ics/hyracks/storage/am/bloomfilter/impls/BloomFilter.java
+++ b/hyracks/hyracks-storage-am-bloomfilter/src/main/java/edu/uci/ics/hyracks/storage/am/bloomfilter/impls/BloomFilter.java
@@ -133,7 +133,7 @@
         metaPage.getBuffer().putInt(NUM_HASHES_USED_OFFSET, 0);
         metaPage.getBuffer().putLong(NUM_ELEMENTS_OFFSET, 0L);
         metaPage.getBuffer().putLong(NUM_BITS_OFFSET, 0L);
-        metaPage.releaseWriteLatch();
+        metaPage.releaseWriteLatch(true);
         bufferCache.unpin(metaPage);
         bufferCache.closeFile(fileId);
     }
@@ -249,7 +249,7 @@
             metaPage.getBuffer().putInt(NUM_HASHES_USED_OFFSET, numHashes);
             metaPage.getBuffer().putLong(NUM_ELEMENTS_OFFSET, numElements);
             metaPage.getBuffer().putLong(NUM_BITS_OFFSET, numBits);
-            metaPage.releaseWriteLatch();
+            metaPage.releaseWriteLatch(true);
             bufferCache.unpin(metaPage);
         }
 
@@ -273,7 +273,7 @@
         public void end() throws HyracksDataException, IndexException {
             for (int i = 0; i < numPages; ++i) {
                 ICachedPage page = bloomFilterPages.get(i);
-                page.releaseWriteLatch();
+                page.releaseWriteLatch(true);
             }
         }
 
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/frames/BTreeNSMInteriorFrame.java b/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/frames/BTreeNSMInteriorFrame.java
index 67392ac..cdaf144 100644
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/frames/BTreeNSMInteriorFrame.java
+++ b/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/frames/BTreeNSMInteriorFrame.java
@@ -185,45 +185,50 @@
         ByteBuffer right = rightFrame.getBuffer();
         int tupleCount = getTupleCount();
 
-        // Find split point, and determine into which frame the new tuple should be inserted into.
-        int tuplesToLeft;
+        // Find split point, and determine into which frame the new tuple should be inserted into.  
         ITreeIndexFrame targetFrame = null;
-
-        int totalSize = 0;
-        int halfPageSize = (buf.capacity() - getPageHeaderSize()) / 2;
-        int i;
-        for (i = 0; i < tupleCount; ++i) {
-            frameTuple.resetByTupleIndex(this, i);
-            totalSize += tupleWriter.bytesRequired(frameTuple) + childPtrSize + slotManager.getSlotSize();
-            if (totalSize >= halfPageSize) {
-                break;
-            }
-        }
-
+        frameTuple.resetByTupleIndex(this, tupleCount - 1);
+        int tuplesToLeft;
         if (cmp.compare(tuple, frameTuple) > 0) {
-            tuplesToLeft = i;
+            // This is a special optimization case when the tuple to be inserted is the largest key on the page.
             targetFrame = rightFrame;
+            tuplesToLeft = tupleCount;
         } else {
-            tuplesToLeft = i + 1;
-            targetFrame = this;
+            int totalSize = 0;
+            int halfPageSize = (buf.capacity() - getPageHeaderSize()) / 2;
+            int i;
+            for (i = 0; i < tupleCount; ++i) {
+                frameTuple.resetByTupleIndex(this, i);
+                totalSize += tupleWriter.bytesRequired(frameTuple) + childPtrSize + slotManager.getSlotSize();
+                if (totalSize >= halfPageSize) {
+                    break;
+                }
+            }
+
+            if (cmp.compare(tuple, frameTuple) > 0) {
+                tuplesToLeft = i;
+                targetFrame = rightFrame;
+            } else {
+                tuplesToLeft = i + 1;
+                targetFrame = this;
+            }
+            int tuplesToRight = tupleCount - tuplesToLeft;
+
+            // Copy entire page.
+            System.arraycopy(buf.array(), 0, right.array(), 0, buf.capacity());
+
+            // On the right page we need to copy rightmost slots to left.
+            int src = rightFrame.getSlotManager().getSlotEndOff();
+            int dest = rightFrame.getSlotManager().getSlotEndOff() + tuplesToLeft
+                    * rightFrame.getSlotManager().getSlotSize();
+            int length = rightFrame.getSlotManager().getSlotSize() * tuplesToRight;
+            System.arraycopy(right.array(), src, right.array(), dest, length);
+            right.putInt(tupleCountOff, tuplesToRight);
+
+            // On the left page, remove the highest key and make its child pointer
+            // the rightmost child pointer.
+            buf.putInt(tupleCountOff, tuplesToLeft);
         }
-        int tuplesToRight = tupleCount - tuplesToLeft;
-
-        // Copy entire page.
-        System.arraycopy(buf.array(), 0, right.array(), 0, buf.capacity());
-
-        // On the right page we need to copy rightmost slots to left.
-        int src = rightFrame.getSlotManager().getSlotEndOff();
-        int dest = rightFrame.getSlotManager().getSlotEndOff() + tuplesToLeft
-                * rightFrame.getSlotManager().getSlotSize();
-        int length = rightFrame.getSlotManager().getSlotSize() * tuplesToRight;
-        System.arraycopy(right.array(), src, right.array(), dest, length);
-        right.putInt(tupleCountOff, tuplesToRight);
-
-        // On the left page, remove the highest key and make its child pointer
-        // the rightmost child pointer.
-        buf.putInt(tupleCountOff, tuplesToLeft);
-
         // Copy the split key to be inserted.
         // We must do so because setting the new split key will overwrite the
         // old split key, and we cannot insert the existing split key at this point.
@@ -245,7 +250,6 @@
         // Compact both pages.
         rightFrame.compact();
         compact();
-
         // Insert the saved split key.
         int targetTupleIndex;
         // it's safe to catch this exception since it will have been caught before reaching here
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/frames/BTreeNSMLeafFrame.java b/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/frames/BTreeNSMLeafFrame.java
index 187cd52..995e8a7 100644
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/frames/BTreeNSMLeafFrame.java
+++ b/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/frames/BTreeNSMLeafFrame.java
@@ -49,7 +49,7 @@
     public int getBytesRequriedToWriteTuple(ITupleReference tuple) {
         return tupleWriter.bytesRequired(tuple) + slotManager.getSlotSize();
     }
-    
+
     @Override
     public void initBuffer(byte level) {
         super.initBuffer(level);
@@ -148,45 +148,51 @@
 
         // Find split point, and determine into which frame the new tuple should
         // be inserted into.
-        int tuplesToLeft;
         ITreeIndexFrame targetFrame = null;
-        int totalSize = 0;
-        int halfPageSize = (buf.capacity() - getPageHeaderSize()) / 2;
-        int i;
-        for (i = 0; i < tupleCount; ++i) {
-            frameTuple.resetByTupleIndex(this, i);
-            totalSize += tupleWriter.getCopySpaceRequired(frameTuple) + slotManager.getSlotSize();
-            if (totalSize >= halfPageSize) {
-                break;
-            }
-        }
-
-        if (cmp.compare(tuple, frameTuple) >= 0) {
-            tuplesToLeft = i + 1;
+        frameTuple.resetByTupleIndex(this, tupleCount - 1);
+        if (cmp.compare(tuple, frameTuple) > 0) {
+            // This is a special optimization case when the tuple to be inserted is the largest key on the page.
             targetFrame = rightFrame;
         } else {
-            tuplesToLeft = i;
-            targetFrame = this;
+            int tuplesToLeft;
+            int totalSize = 0;
+            int halfPageSize = (buf.capacity() - getPageHeaderSize()) / 2;
+            int i;
+            for (i = 0; i < tupleCount; ++i) {
+                frameTuple.resetByTupleIndex(this, i);
+                totalSize += tupleWriter.getCopySpaceRequired(frameTuple) + slotManager.getSlotSize();
+                if (totalSize >= halfPageSize) {
+                    break;
+                }
+            }
+
+            if (cmp.compare(tuple, frameTuple) >= 0) {
+                tuplesToLeft = i + 1;
+                targetFrame = rightFrame;
+            } else {
+                tuplesToLeft = i;
+                targetFrame = this;
+            }
+            int tuplesToRight = tupleCount - tuplesToLeft;
+
+            // Copy entire page.
+            System.arraycopy(buf.array(), 0, right.array(), 0, buf.capacity());
+
+            // On the right page we need to copy rightmost slots to the left.
+            int src = rightFrame.getSlotManager().getSlotEndOff();
+            int dest = rightFrame.getSlotManager().getSlotEndOff() + tuplesToLeft
+                    * rightFrame.getSlotManager().getSlotSize();
+            int length = rightFrame.getSlotManager().getSlotSize() * tuplesToRight;
+            System.arraycopy(right.array(), src, right.array(), dest, length);
+            right.putInt(tupleCountOff, tuplesToRight);
+
+            // On left page only change the tupleCount indicator.
+            buf.putInt(tupleCountOff, tuplesToLeft);
+
+            // Compact both pages.
+            rightFrame.compact();
+            compact();
         }
-        int tuplesToRight = tupleCount - tuplesToLeft;
-
-        // Copy entire page.
-        System.arraycopy(buf.array(), 0, right.array(), 0, buf.capacity());
-
-        // On the right page we need to copy rightmost slots to the left.
-        int src = rightFrame.getSlotManager().getSlotEndOff();
-        int dest = rightFrame.getSlotManager().getSlotEndOff() + tuplesToLeft
-                * rightFrame.getSlotManager().getSlotSize();
-        int length = rightFrame.getSlotManager().getSlotSize() * tuplesToRight;
-        System.arraycopy(right.array(), src, right.array(), dest, length);
-        right.putInt(tupleCountOff, tuplesToRight);
-
-        // On left page only change the tupleCount indicator.
-        buf.putInt(tupleCountOff, tuplesToLeft);
-
-        // Compact both pages.
-        rightFrame.compact();
-        compact();
 
         // Insert the new tuple.
         int targetTupleIndex;
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/frames/OrderedSlotManager.java b/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/frames/OrderedSlotManager.java
index 2071a77..2316c6b 100644
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/frames/OrderedSlotManager.java
+++ b/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/frames/OrderedSlotManager.java
@@ -27,19 +27,29 @@
     @Override
     public int findTupleIndex(ITupleReference searchKey, ITreeIndexTupleReference frameTuple, MultiComparator multiCmp,
             FindTupleMode mode, FindTupleNoExactMatchPolicy matchPolicy) {
-        if (frame.getTupleCount() <= 0) {
+        int tupleCount = frame.getTupleCount();
+        if (tupleCount <= 0) {
             return GREATEST_KEY_INDICATOR;
         }
 
         int mid;
-        int begin = 0;
-        int end = frame.getTupleCount() - 1;
+        int begin;
+        int end = tupleCount - 1;
+
+        frameTuple.resetByTupleIndex(frame, end);
+        int cmp = multiCmp.compare(searchKey, frameTuple);
+        if (cmp > 0) {
+            // This is a special optimization case when the tuple to be searched is larger than all the keys on the page.
+            begin = tupleCount;
+        } else {
+            begin = 0;
+        }
 
         while (begin <= end) {
             mid = (begin + end) / 2;
             frameTuple.resetByTupleIndex(frame, mid);
 
-            int cmp = multiCmp.compare(searchKey, frameTuple);
+            cmp = multiCmp.compare(searchKey, frameTuple);
             if (cmp < 0) {
                 end = mid - 1;
             } else if (cmp > 0) {
@@ -66,7 +76,7 @@
         }
 
         if (matchPolicy == FindTupleNoExactMatchPolicy.HIGHER_KEY) {
-            if (begin > frame.getTupleCount() - 1) {
+            if (begin > tupleCount - 1) {
                 return GREATEST_KEY_INDICATOR;
             }
             frameTuple.resetByTupleIndex(frame, begin);
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/impls/BTree.java b/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/impls/BTree.java
index ff94040..fef0f81 100644
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/impls/BTree.java
+++ b/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/impls/BTree.java
@@ -217,7 +217,7 @@
                 ctx.interiorFrame.setPage(smPage);
                 ctx.interiorFrame.setSmFlag(false);
             } finally {
-                smPage.releaseWriteLatch();
+                smPage.releaseWriteLatch(true);
                 bufferCache.unpin(smPage);
             }
         }
@@ -261,11 +261,11 @@
                 int targetTupleIndex = ctx.interiorFrame.findInsertTupleIndex(ctx.splitKey.getTuple());
                 ctx.interiorFrame.insert(ctx.splitKey.getTuple(), targetTupleIndex);
             } finally {
-                newLeftNode.releaseWriteLatch();
+                newLeftNode.releaseWriteLatch(true);
                 bufferCache.unpin(newLeftNode);
             }
         } finally {
-            leftNode.releaseWriteLatch();
+            leftNode.releaseWriteLatch(true);
             bufferCache.unpin(leftNode);
         }
     }
@@ -447,7 +447,7 @@
             treeLatch.writeLock().unlock();
             throw e;
         } finally {
-            rightNode.releaseWriteLatch();
+            rightNode.releaseWriteLatch(true);
             bufferCache.unpin(rightNode);
         }
         return false;
@@ -533,7 +533,7 @@
 
                     ctx.splitKey.setPages(pageId, rightPageId);
                 } finally {
-                    rightNode.releaseWriteLatch();
+                    rightNode.releaseWriteLatch(true);
                     bufferCache.unpin(rightNode);
                 }
                 break;
@@ -616,7 +616,7 @@
                 if (parentIsReadLatched) {
                     parent.releaseReadLatch();
                 } else {
-                    parent.releaseWriteLatch();
+                    parent.releaseWriteLatch(true);
                 }
                 bufferCache.unpin(parent);
             }
@@ -664,7 +664,7 @@
                                         // Insert or update op. Both can cause split keys to propagate upwards. 
                                         insertInterior(interiorNode, pageId, ctx.splitKey.getTuple(), ctx);
                                     } finally {
-                                        interiorNode.releaseWriteLatch();
+                                        interiorNode.releaseWriteLatch(true);
                                         bufferCache.unpin(interiorNode);
                                     }
                                 } else {
@@ -694,7 +694,7 @@
                     if (isReadLatched) {
                         node.releaseReadLatch();
                     } else {
-                        node.releaseWriteLatch();
+                        node.releaseWriteLatch(true);
                     }
                     bufferCache.unpin(node);
 
@@ -747,7 +747,7 @@
                     }
                 }
                 if (ctx.op != IndexOperation.SEARCH) {
-                    node.releaseWriteLatch();
+                    node.releaseWriteLatch(true);
                     bufferCache.unpin(node);
                 }
                 if (restartOp) {
@@ -764,7 +764,7 @@
                     if (isReadLatched) {
                         node.releaseReadLatch();
                     } else {
-                        node.releaseWriteLatch();
+                        node.releaseWriteLatch(true);
                     }
                     bufferCache.unpin(node);
                     ctx.exceptionHandled = true;
@@ -777,7 +777,7 @@
                 if (isReadLatched) {
                     node.releaseReadLatch();
                 } else {
-                    node.releaseWriteLatch();
+                    node.releaseWriteLatch(true);
                 }
                 bufferCache.unpin(node);
             }
@@ -897,9 +897,9 @@
         }
 
         @Override
-        public ITreeIndexCursor createSearchCursor() {
+        public ITreeIndexCursor createSearchCursor(boolean exclusive) {
             IBTreeLeafFrame leafFrame = (IBTreeLeafFrame) btree.getLeafFrameFactory().createFrame();
-            return new BTreeRangeSearchCursor(leafFrame, false);
+            return new BTreeRangeSearchCursor(leafFrame, exclusive);
         }
 
         @Override
@@ -990,7 +990,7 @@
                     leafFrontier.pageId = freePageManager.getFreePage(metaFrame);
 
                     ((IBTreeLeafFrame) leafFrame).setNextLeaf(leafFrontier.pageId);
-                    leafFrontier.page.releaseWriteLatch();
+                    leafFrontier.page.releaseWriteLatch(true);
                     bufferCache.unpin(leafFrontier.page);
 
                     splitKey.setRightPage(leafFrontier.pageId);
@@ -1062,7 +1062,7 @@
 
                 ((IBTreeInteriorFrame) interiorFrame).deleteGreatest();
 
-                frontier.page.releaseWriteLatch();
+                frontier.page.releaseWriteLatch(true);
                 bufferCache.unpin(frontier.page);
                 frontier.pageId = freePageManager.getFreePage(metaFrame);
 
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/impls/BTreeCountingSearchCursor.java b/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/impls/BTreeCountingSearchCursor.java
index ee65a46..38c1624 100644
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/impls/BTreeCountingSearchCursor.java
+++ b/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/impls/BTreeCountingSearchCursor.java
@@ -51,6 +51,7 @@
     private final IBTreeLeafFrame frame;
     private final ITreeIndexTupleReference frameTuple;
     private final boolean exclusiveLatchNodes;
+    private boolean isPageDirty;
 
     private RangePredicate pred;
     private MultiComparator lowKeyCmp;
@@ -61,8 +62,8 @@
     // For storing the count.
     private byte[] countBuf = new byte[4];
     private ArrayTupleBuilder tupleBuilder = new ArrayTupleBuilder(1);
-    private ArrayTupleReference countTuple = new ArrayTupleReference();    
-    
+    private ArrayTupleReference countTuple = new ArrayTupleReference();
+
     public BTreeCountingSearchCursor(IBTreeLeafFrame frame, boolean exclusiveLatchNodes) {
         this.frame = frame;
         this.frameTuple = frame.createTupleReference();
@@ -74,7 +75,7 @@
         // in case open is called multiple times without closing
         if (page != null) {
             if (exclusiveLatchNodes) {
-                page.releaseWriteLatch();
+                page.releaseWriteLatch(isPageDirty);
             } else {
                 page.releaseReadLatch();
             }
@@ -82,6 +83,7 @@
         }
 
         page = ((BTreeCursorInitialState) initialState).getPage();
+        isPageDirty = false;
         frame.setPage(page);
 
         pred = (RangePredicate) searchPred;
@@ -107,7 +109,7 @@
         }
 
         tupleIndex = getLowKeyIndex();
-        stopTupleIndex = getHighKeyIndex();        
+        stopTupleIndex = getHighKeyIndex();
     }
 
     private void fetchNextLeafPage(int nextLeafPage) throws HyracksDataException {
@@ -115,13 +117,14 @@
             ICachedPage nextLeaf = bufferCache.pin(BufferedFileHandle.getDiskPageId(fileId, nextLeafPage), false);
             if (exclusiveLatchNodes) {
                 nextLeaf.acquireWriteLatch();
-                page.releaseWriteLatch();
+                page.releaseWriteLatch(isPageDirty);
             } else {
                 nextLeaf.acquireReadLatch();
                 page.releaseReadLatch();
             }
             bufferCache.unpin(page);
             page = nextLeaf;
+            isPageDirty = false;
             frame.setPage(page);
             nextLeafPage = frame.getNextLeaf();
         } while (frame.getTupleCount() == 0 && nextLeafPage > 0);
@@ -199,7 +202,7 @@
     public void close() throws HyracksDataException {
         if (page != null) {
             if (exclusiveLatchNodes) {
-                page.releaseWriteLatch();
+                page.releaseWriteLatch(isPageDirty);
             } else {
                 page.releaseReadLatch();
             }
@@ -208,6 +211,7 @@
         tupleBuilder.reset();
         tupleIndex = 0;
         page = null;
+        isPageDirty = false;
         pred = null;
         count = -1;
     }
@@ -218,7 +222,7 @@
             close();
         } catch (Exception e) {
             e.printStackTrace();
-        }        
+        }
     }
 
     @Override
@@ -246,4 +250,13 @@
         return exclusiveLatchNodes;
     }
 
+    @Override
+    public void markCurrentTupleAsUpdated() throws HyracksDataException {
+        if (exclusiveLatchNodes) {
+            isPageDirty = true;
+        } else {
+            throw new HyracksDataException("This cursor has not been created with the intention to allow updates.");
+        }
+    }
+
 }
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/impls/BTreeRangeSearchCursor.java b/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/impls/BTreeRangeSearchCursor.java
index 4546b0e..584af4e 100644
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/impls/BTreeRangeSearchCursor.java
+++ b/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/impls/BTreeRangeSearchCursor.java
@@ -40,6 +40,7 @@
     private final IBTreeLeafFrame frame;
     private final ITreeIndexTupleReference frameTuple;
     private final boolean exclusiveLatchNodes;
+    private boolean isPageDirty;
 
     private IBufferCache bufferCache = null;
     private int fileId = -1;
@@ -80,7 +81,7 @@
     public void close() throws HyracksDataException {
         if (page != null) {
             if (exclusiveLatchNodes) {
-                page.releaseWriteLatch();
+                page.releaseWriteLatch(isPageDirty);
             } else {
                 page.releaseReadLatch();
             }
@@ -89,6 +90,7 @@
 
         tupleIndex = 0;
         page = null;
+        isPageDirty = false;
         pred = null;
     }
 
@@ -114,7 +116,7 @@
             ICachedPage nextLeaf = bufferCache.pin(BufferedFileHandle.getDiskPageId(fileId, nextLeafPage), false);
             if (exclusiveLatchNodes) {
                 nextLeaf.acquireWriteLatch();
-                page.releaseWriteLatch();
+                page.releaseWriteLatch(isPageDirty);
             } else {
                 nextLeaf.acquireReadLatch();
                 page.releaseReadLatch();
@@ -122,6 +124,7 @@
             bufferCache.unpin(page);
 
             page = nextLeaf;
+            isPageDirty = false;
             frame.setPage(page);
             pageId = nextLeafPage;
             nextLeafPage = frame.getNextLeaf();
@@ -163,12 +166,13 @@
 
                 // unlatch/unpin
                 if (exclusiveLatchNodes) {
-                    page.releaseWriteLatch();
+                    page.releaseWriteLatch(isPageDirty);
                 } else {
                     page.releaseReadLatch();
                 }
                 bufferCache.unpin(page);
                 page = null;
+                isPageDirty = false;
 
                 // reconcile
                 searchCb.reconcile(reconciliationTuple);
@@ -240,7 +244,7 @@
         // in case open is called multiple times without closing
         if (page != null) {
             if (exclusiveLatchNodes) {
-                page.releaseWriteLatch();
+                page.releaseWriteLatch(isPageDirty);
             } else {
                 page.releaseReadLatch();
             }
@@ -251,6 +255,7 @@
         originalKeyCmp = initialState.getOriginalKeyComparator();
         pageId = ((BTreeCursorInitialState) initialState).getPageId();
         page = initialState.getPage();
+        isPageDirty = false;
         frame.setPage(page);
 
         pred = (RangePredicate) searchPred;
@@ -300,4 +305,13 @@
     public boolean exclusiveLatchNodes() {
         return exclusiveLatchNodes;
     }
+
+    @Override
+    public void markCurrentTupleAsUpdated() throws HyracksDataException {
+        if (exclusiveLatchNodes) {
+            isPageDirty = true;
+        } else {
+            throw new HyracksDataException("This cursor has not been created with the intention to allow updates.");
+        }
+    }
 }
\ No newline at end of file
diff --git a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/IIndexAccessor.java b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/IIndexAccessor.java
index 5eb3cdd..a9aaad8 100644
--- a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/IIndexAccessor.java
+++ b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/IIndexAccessor.java
@@ -83,7 +83,7 @@
      * Creates a cursor appropriate for passing into search().
      * 
      */
-    public IIndexCursor createSearchCursor();
+    public IIndexCursor createSearchCursor(boolean exclusive);
 
     /**
      * Open the given cursor for an index search using the given predicate as
diff --git a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/ITreeIndexCursor.java b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/ITreeIndexCursor.java
index 5102d27..a097425 100644
--- a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/ITreeIndexCursor.java
+++ b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/ITreeIndexCursor.java
@@ -15,17 +15,20 @@
 
 package edu.uci.ics.hyracks.storage.am.common.api;
 
+import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.storage.common.buffercache.IBufferCache;
 import edu.uci.ics.hyracks.storage.common.buffercache.ICachedPage;
 
 public interface ITreeIndexCursor extends IIndexCursor {
 
-	public ICachedPage getPage();
+    public ICachedPage getPage();
 
-	public void setBufferCache(IBufferCache bufferCache);
+    public void setBufferCache(IBufferCache bufferCache);
 
-	public void setFileId(int fileId);
+    public void setFileId(int fileId);
 
-	// For allowing updates.
-	public boolean exclusiveLatchNodes();
+    // For allowing updates.
+    public boolean exclusiveLatchNodes();
+
+    public void markCurrentTupleAsUpdated() throws HyracksDataException;
 }
diff --git a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/IndexSearchOperatorNodePushable.java b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/IndexSearchOperatorNodePushable.java
index 83fb5ee..2696af9 100644
--- a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/IndexSearchOperatorNodePushable.java
+++ b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/IndexSearchOperatorNodePushable.java
@@ -70,7 +70,7 @@
     protected abstract void resetSearchPredicate(int tupleIndex);
 
     protected IIndexCursor createCursor() {
-        return indexAccessor.createSearchCursor();
+        return indexAccessor.createSearchCursor(false);
     }
 
     @Override
diff --git a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenThread.java b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenThread.java
index 6e17ff8..9c2268d 100644
--- a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenThread.java
+++ b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenThread.java
@@ -23,21 +23,20 @@
 import edu.uci.ics.hyracks.api.dataflow.value.ISerializerDeserializer;
 
 /**
- * Quick & dirty data generator for multi-thread testing. 
- *
+ * Quick & dirty data generator for multi-thread testing.
  */
 @SuppressWarnings("rawtypes")
 public class DataGenThread extends Thread {
     public final BlockingQueue<TupleBatch> tupleBatchQueue;
     private final int maxNumBatches;
-    private final int maxOutstandingBatches;        
+    private final int maxOutstandingBatches;
     private int numBatches = 0;
     private final Random rnd;
-    
+
     // maxOutstandingBatches pre-created tuple-batches for populating the queue.
     private TupleBatch[] tupleBatches;
     private int ringPos;
-    
+
     public DataGenThread(int numConsumers, int maxNumBatches, int batchSize, ISerializerDeserializer[] fieldSerdes,
             int payloadSize, int rndSeed, int maxOutstandingBatches, boolean sorted) {
         this.maxNumBatches = maxNumBatches;
@@ -51,7 +50,7 @@
         tupleBatchQueue = new LinkedBlockingQueue<TupleBatch>(maxOutstandingBatches);
         ringPos = 0;
     }
-    
+
     public DataGenThread(int numConsumers, int maxNumBatches, int batchSize, ISerializerDeserializer[] fieldSerdes,
             IFieldValueGenerator[] fieldGens, int rndSeed, int maxOutstandingBatches) {
         this.maxNumBatches = maxNumBatches;
@@ -64,13 +63,13 @@
         tupleBatchQueue = new LinkedBlockingQueue<TupleBatch>(maxOutstandingBatches);
         ringPos = 0;
     }
-    
+
     @Override
     public void run() {
-        while(numBatches < maxNumBatches) {
+        while (numBatches < maxNumBatches) {
             boolean added = false;
             try {
-                if (tupleBatches[ringPos].inUse.compareAndSet(false, true)) {                    
+                if (tupleBatches[ringPos].inUse.compareAndSet(false, true)) {
                     tupleBatches[ringPos].generate();
                     tupleBatchQueue.put(tupleBatches[ringPos]);
                     added = true;
@@ -89,11 +88,11 @@
             }
         }
     }
-    
+
     public TupleBatch getBatch() throws InterruptedException {
         return tupleBatchQueue.take();
     }
-    
+
     public void releaseBatch(TupleBatch batch) {
         batch.inUse.set(false);
     }
diff --git a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenUtils.java b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenUtils.java
index d7234fa..cb9c545 100644
--- a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenUtils.java
+++ b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenUtils.java
@@ -23,7 +23,7 @@
 import edu.uci.ics.hyracks.dataflow.common.data.marshalling.IntegerSerializerDeserializer;
 import edu.uci.ics.hyracks.dataflow.common.data.marshalling.UTF8StringSerializerDeserializer;
 
-@SuppressWarnings("rawtypes") 
+@SuppressWarnings("rawtypes")
 public class DataGenUtils {
     public static IFieldValueGenerator getFieldGenFromSerde(ISerializerDeserializer serde, Random rnd, boolean sorted) {
         if (serde instanceof IntegerSerializerDeserializer) {
@@ -49,8 +49,9 @@
         }
         return null;
     }
-    
-    public static IFieldValueGenerator[] getFieldGensFromSerdes(ISerializerDeserializer[] serdes, Random rnd, boolean sorted) {
+
+    public static IFieldValueGenerator[] getFieldGensFromSerdes(ISerializerDeserializer[] serdes, Random rnd,
+            boolean sorted) {
         IFieldValueGenerator[] fieldValueGens = new IFieldValueGenerator[serdes.length];
         for (int i = 0; i < serdes.length; i++) {
             fieldValueGens[i] = getFieldGenFromSerde(serdes[i], rnd, sorted);
diff --git a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/freepage/LinkedListFreePageManager.java b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/freepage/LinkedListFreePageManager.java
index 2e25f4c..a51ce98 100644
--- a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/freepage/LinkedListFreePageManager.java
+++ b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/freepage/LinkedListFreePageManager.java
@@ -77,14 +77,14 @@
 					metaFrame.setMaxPage(metaMaxPage);
 					metaFrame.addFreePage(freePage);
 				} finally {
-					newNode.releaseWriteLatch();
+					newNode.releaseWriteLatch(true);
 					bufferCache.unpin(newNode);
 				}
 			}
 		} catch (Exception e) {
 			e.printStackTrace();
 		} finally {
-			metaNode.releaseWriteLatch();
+			metaNode.releaseWriteLatch(true);
 			bufferCache.unpin(metaNode);
 		}
 	}
@@ -136,7 +136,7 @@
 							metaFrame.addFreePage(nextPage);
 						}
 					} finally {
-						nextNode.releaseWriteLatch();
+						nextNode.releaseWriteLatch(true);
 						bufferCache.unpin(nextNode);
 					}
 				} else {
@@ -146,7 +146,7 @@
 				}
 			}
 		} finally {
-			metaNode.releaseWriteLatch();
+			metaNode.releaseWriteLatch(true);
 			bufferCache.unpin(metaNode);
 		}
 
@@ -164,7 +164,7 @@
 			metaFrame.setPage(metaNode);
 			maxPage = metaFrame.getMaxPage();
 		} finally {
-			metaNode.releaseWriteLatch();
+			metaNode.releaseWriteLatch(true);
 			bufferCache.unpin(metaNode);
 		}
 		return maxPage;
@@ -183,7 +183,7 @@
 			metaFrame.initBuffer(META_PAGE_LEVEL_INDICATOR);
 			metaFrame.setMaxPage(currentMaxPage);
 		} finally {
-			metaNode.releaseWriteLatch();
+			metaNode.releaseWriteLatch(true);
 			bufferCache.unpin(metaNode);
 		}
 	}
diff --git a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/impls/AbstractTreeIndex.java b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/impls/AbstractTreeIndex.java
index c14f23a..e191fd0 100644
--- a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/impls/AbstractTreeIndex.java
+++ b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/impls/AbstractTreeIndex.java
@@ -111,7 +111,7 @@
             frame.setPage(rootNode);
             frame.initBuffer((byte) 0);
         } finally {
-            rootNode.releaseWriteLatch();
+            rootNode.releaseWriteLatch(true);
             bufferCache.unpin(rootNode);
         }
     }
@@ -264,7 +264,7 @@
                 throw new TreeIndexException("Cannot bulk-load a non-empty tree.");
             }
 
-            this.cmp = MultiComparator.createIgnoreFieldLength(cmpFactories);
+            this.cmp = MultiComparator.create(cmpFactories);
 
             leafFrame.setMultiComparator(cmp);
             interiorFrame.setMultiComparator(cmp);
@@ -293,7 +293,7 @@
         protected void handleException() throws HyracksDataException {
             // Unlatch and unpin pages.
             for (NodeFrontier nodeFrontier : nodeFrontiers) {
-                nodeFrontier.page.releaseWriteLatch();
+                nodeFrontier.page.releaseWriteLatch(true);
                 bufferCache.unpin(nodeFrontier.page);
             }
             releasedLatches = true;
@@ -309,7 +309,7 @@
                 System.arraycopy(lastNodeFrontier.page.getBuffer().array(), 0, newRoot.getBuffer().array(), 0,
                         lastNodeFrontier.page.getBuffer().capacity());
             } finally {
-                newRoot.releaseWriteLatch();
+                newRoot.releaseWriteLatch(true);
                 bufferCache.unpin(newRoot);
 
                 // register old root as a free page
@@ -318,7 +318,7 @@
                 if (!releasedLatches) {
                     for (int i = 0; i < nodeFrontiers.size(); i++) {
                         try {
-                            nodeFrontiers.get(i).page.releaseWriteLatch();
+                            nodeFrontiers.get(i).page.releaseWriteLatch(true);
                         } catch (Exception e) {
                             //ignore illegal monitor state exception
                         }
diff --git a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/impls/TreeIndexDiskOrderScanCursor.java b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/impls/TreeIndexDiskOrderScanCursor.java
index 0f97b0d..7592348 100644
--- a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/impls/TreeIndexDiskOrderScanCursor.java
+++ b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/impls/TreeIndexDiskOrderScanCursor.java
@@ -147,4 +147,9 @@
     public boolean exclusiveLatchNodes() {
         return false;
     }
+
+    @Override
+    public void markCurrentTupleAsUpdated() throws HyracksDataException {
+        throw new HyracksDataException("Updating tuples is not supported with this cursor.");
+    }
 }
diff --git a/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTree.java b/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTree.java
index 3e51e20..cb4d268 100644
--- a/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTree.java
+++ b/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTree.java
@@ -54,7 +54,6 @@
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMHarness;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperationCallback;
-import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperationCallbackProvider;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperationScheduler;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexAccessorInternal;
@@ -164,8 +163,7 @@
         }
 
         if (flushOnExit) {
-            BlockingIOOperationCallbackWrapper cb = new BlockingIOOperationCallbackWrapper(
-                    ioOpCallback);
+            BlockingIOOperationCallbackWrapper cb = new BlockingIOOperationCallbackWrapper(ioOpCallback);
             ILSMIndexAccessor accessor = createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
             accessor.scheduleFlush(cb);
             try {
@@ -370,7 +368,8 @@
         opCtx.getComponentHolder().add(flushingComponent);
         ILSMIndexAccessorInternal flushAccessor = new LSMBTreeAccessor(lsmHarness, opCtx);
         ioScheduler.scheduleOperation(new LSMBTreeFlushOperation(flushAccessor, flushingComponent, componentFileRefs
-                .getInsertIndexFileReference(), componentFileRefs.getBloomFilterFileReference(), callback));
+                .getInsertIndexFileReference(), componentFileRefs.getBloomFilterFileReference(), callback, fileManager
+                .getBaseDir()));
     }
 
     @Override
@@ -405,7 +404,7 @@
         IIndexBulkLoader builder = component.getBloomFilter().createBuilder(numElements,
                 bloomFilterSpec.getNumHashes(), bloomFilterSpec.getNumBucketsPerElements());
 
-        IIndexCursor scanCursor = accessor.createSearchCursor();
+        IIndexCursor scanCursor = accessor.createSearchCursor(false);
         accessor.search(scanCursor, nullPred);
         try {
             while (scanCursor.hasNext()) {
@@ -442,7 +441,8 @@
                 .getName(), lastFile.getFile().getName());
         ILSMIndexAccessorInternal accessor = new LSMBTreeAccessor(lsmHarness, opCtx);
         ioScheduler.scheduleOperation(new LSMBTreeMergeOperation(accessor, mergingComponents, cursor, relMergeFileRefs
-                .getInsertIndexFileReference(), relMergeFileRefs.getBloomFilterFileReference(), callback));
+                .getInsertIndexFileReference(), relMergeFileRefs.getBloomFilterFileReference(), callback, fileManager
+                .getBaseDir()));
     }
 
     @Override
@@ -622,7 +622,7 @@
         }
 
         @Override
-        public IIndexCursor createSearchCursor() {
+        public IIndexCursor createSearchCursor(boolean exclusive) {
             return new LSMBTreeSearchCursor(ctx);
         }
 
diff --git a/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreeFlushOperation.java b/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreeFlushOperation.java
index 668e727..94b1569 100644
--- a/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreeFlushOperation.java
+++ b/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreeFlushOperation.java
@@ -27,21 +27,24 @@
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperationCallback;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexAccessorInternal;
 
-public class LSMBTreeFlushOperation implements ILSMIOOperation {
+public class LSMBTreeFlushOperation implements ILSMIOOperation, Comparable<LSMBTreeFlushOperation> {
 
     private final ILSMIndexAccessorInternal accessor;
     private final ILSMComponent flushingComponent;
     private final FileReference btreeFlushTarget;
     private final FileReference bloomFilterFlushTarget;
     private final ILSMIOOperationCallback callback;
+    private final String indexIdentifier;
 
     public LSMBTreeFlushOperation(ILSMIndexAccessorInternal accessor, ILSMComponent flushingComponent,
-            FileReference btreeFlushTarget, FileReference bloomFilterFlushTarget, ILSMIOOperationCallback callback) {
+            FileReference btreeFlushTarget, FileReference bloomFilterFlushTarget, ILSMIOOperationCallback callback,
+            String indexIdentifier) {
         this.accessor = accessor;
         this.flushingComponent = flushingComponent;
         this.btreeFlushTarget = btreeFlushTarget;
         this.bloomFilterFlushTarget = bloomFilterFlushTarget;
         this.callback = callback;
+        this.indexIdentifier = indexIdentifier;
     }
 
     @Override
@@ -83,4 +86,19 @@
     public ILSMComponent getFlushingComponent() {
         return flushingComponent;
     }
+
+    @Override
+    public String getIndexUniqueIdentifier() {
+        return indexIdentifier;
+    }
+
+    @Override
+    public LSMIOOpertionType getIOOpertionType() {
+        return LSMIOOpertionType.FLUSH;
+    }
+
+    @Override
+    public int compareTo(LSMBTreeFlushOperation o) {
+        return btreeFlushTarget.getFile().getName().compareTo(o.getBTreeFlushTarget().getFile().getName());
+    }
 }
diff --git a/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreeMergeOperation.java b/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreeMergeOperation.java
index 3a608fe..a4f6875 100644
--- a/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreeMergeOperation.java
+++ b/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreeMergeOperation.java
@@ -37,16 +37,18 @@
     private final FileReference btreeMergeTarget;
     private final FileReference bloomFilterMergeTarget;
     private final ILSMIOOperationCallback callback;
+    private final String indexIdentifier;
 
     public LSMBTreeMergeOperation(ILSMIndexAccessorInternal accessor, List<ILSMComponent> mergingComponents,
             ITreeIndexCursor cursor, FileReference btreeMergeTarget, FileReference bloomFilterMergeTarget,
-            ILSMIOOperationCallback callback) {
+            ILSMIOOperationCallback callback, String indexIdentifier) {
         this.accessor = accessor;
         this.mergingComponents = mergingComponents;
         this.cursor = cursor;
         this.btreeMergeTarget = btreeMergeTarget;
         this.bloomFilterMergeTarget = bloomFilterMergeTarget;
         this.callback = callback;
+        this.indexIdentifier = indexIdentifier;
     }
 
     @Override
@@ -94,4 +96,14 @@
     public List<ILSMComponent> getMergingComponents() {
         return mergingComponents;
     }
+
+    @Override
+    public String getIndexUniqueIdentifier() {
+        return indexIdentifier;
+    }
+
+    @Override
+    public LSMIOOpertionType getIOOpertionType() {
+        return LSMIOOpertionType.MERGE;
+    }
 }
diff --git a/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreePointSearchCursor.java b/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreePointSearchCursor.java
index fc09a74..7aba7b3 100644
--- a/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreePointSearchCursor.java
+++ b/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreePointSearchCursor.java
@@ -219,4 +219,9 @@
     public boolean exclusiveLatchNodes() {
         return false;
     }
+
+    @Override
+    public void markCurrentTupleAsUpdated() throws HyracksDataException {
+        throw new HyracksDataException("Updating tuples is not supported with this cursor.");
+    }
 }
\ No newline at end of file
diff --git a/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreeSearchCursor.java b/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreeSearchCursor.java
index 366fc10..dd99833 100644
--- a/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreeSearchCursor.java
+++ b/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreeSearchCursor.java
@@ -129,4 +129,8 @@
         return currentCursor.exclusiveLatchNodes();
     }
 
+    @Override
+    public void markCurrentTupleAsUpdated() throws HyracksDataException {
+        throw new HyracksDataException("Updating tuples is not supported with this cursor.");
+    }
 }
\ No newline at end of file
diff --git a/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMIOOperation.java b/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMIOOperation.java
index 2c3940f..1638a5d 100644
--- a/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMIOOperation.java
+++ b/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMIOOperation.java
@@ -22,6 +22,12 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
 
 public interface ILSMIOOperation extends Callable<Boolean> {
+
+    public enum LSMIOOpertionType {
+        FLUSH,
+        MERGE
+    }
+
     public Set<IODeviceHandle> getReadDevices();
 
     public Set<IODeviceHandle> getWriteDevices();
@@ -29,4 +35,8 @@
     public Boolean call() throws HyracksDataException, IndexException;
 
     public ILSMIOOperationCallback getCallback();
+
+    public String getIndexUniqueIdentifier();
+
+    public LSMIOOpertionType getIOOpertionType();
 }
diff --git a/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/AbstractLSMIndex.java b/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/AbstractLSMIndex.java
index 44bcfc2..3d7512f 100644
--- a/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/AbstractLSMIndex.java
+++ b/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/AbstractLSMIndex.java
@@ -125,16 +125,25 @@
         try {
             metadataFrame.setPage(metadataPage);
             metadataFrame.setValid(true);
-
-            // Flush the single modified page to disk.
-            bufferCache.flushDirtyPage(metadataPage);
-
-            // Force modified metadata page to disk.
-            bufferCache.force(fileId, true);
         } finally {
-            metadataPage.releaseWriteLatch();
+            metadataPage.releaseWriteLatch(true);
             bufferCache.unpin(metadataPage);
         }
+
+        // WARNING: flushing the metadata page should be done after releasing the write latch; otherwise, the page 
+        // won't be flushed to disk because it won't be dirty until the write latch has been released.
+        metadataPage = bufferCache.tryPin(BufferedFileHandle.getDiskPageId(fileId, metadataPageId));
+        if (metadataPage != null) {
+            try {
+                // Flush the single modified page to disk.
+                bufferCache.flushDirtyPage(metadataPage);
+            } finally {
+                bufferCache.unpin(metadataPage);
+            }
+        }
+
+        // Force modified metadata page to disk.
+        bufferCache.force(fileId, true);
     }
 
     @Override
diff --git a/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/AsynchronousScheduler.java b/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/AsynchronousScheduler.java
index 25894f1..b785764 100644
--- a/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/AsynchronousScheduler.java
+++ b/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/AsynchronousScheduler.java
@@ -14,24 +14,87 @@
  */
 package edu.uci.ics.hyracks.storage.am.lsm.common.impls;
 
+import java.util.HashMap;
+import java.util.Map;
+import java.util.PriorityQueue;
+import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
+import java.util.concurrent.RunnableFuture;
+import java.util.concurrent.SynchronousQueue;
 import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
 
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation;
+import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation.LSMIOOpertionType;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperationScheduler;
 
 public class AsynchronousScheduler implements ILSMIOOperationScheduler {
+    // Since this is a asynchronous scheduler, we make sure that flush operations coming from the same lsm index
+    // will be executed serially in same order of scheduling the operations. Look at asterix issue 630.
+
     public final static AsynchronousScheduler INSTANCE = new AsynchronousScheduler();
     private ExecutorService executor;
+    private final Map<String, ILSMIOOperation> runningFlushOperations = new HashMap<String, ILSMIOOperation>();
+    private final Map<String, PriorityQueue<ILSMIOOperation>> waitingFlushOperations = new HashMap<String, PriorityQueue<ILSMIOOperation>>();
 
     public void init(ThreadFactory threadFactory) {
-        executor = Executors.newCachedThreadPool(threadFactory);
+        // Creating an executor with the same configuration of Executors.newCachedThreadPool. 
+        executor = new ThreadPoolExecutor(0, Integer.MAX_VALUE, 60L, TimeUnit.SECONDS,
+                new SynchronousQueue<Runnable>(), threadFactory) {
+
+            @Override
+            protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) {
+                return new LSMIOOperationTask<T>(callable);
+            }
+
+            @SuppressWarnings("unchecked")
+            @Override
+            protected void afterExecute(Runnable r, Throwable t) {
+                super.afterExecute(r, t);
+                LSMIOOperationTask<Boolean> task = (LSMIOOperationTask<Boolean>) r;
+                ILSMIOOperation executedOp = task.getOperation();
+                String id = executedOp.getIndexUniqueIdentifier();
+                synchronized (this) {
+                    runningFlushOperations.remove(id);
+                    if (waitingFlushOperations.containsKey(id)) {
+                        try {
+                            ILSMIOOperation op = waitingFlushOperations.get(id).poll();
+                            if (op != null) {
+                                scheduleOperation(op);
+                            } else {
+                                waitingFlushOperations.remove(id);
+                            }
+                        } catch (HyracksDataException e) {
+                            t = e.getCause();
+                        }
+                    }
+                }
+            }
+        };
     }
 
     @Override
     public void scheduleOperation(ILSMIOOperation operation) throws HyracksDataException {
-        executor.submit(operation);
+        if (operation.getIOOpertionType() == LSMIOOpertionType.MERGE) {
+            executor.submit(operation);
+        } else {
+            String id = operation.getIndexUniqueIdentifier();
+            synchronized (executor) {
+                if (runningFlushOperations.containsKey(id)) {
+                    if (waitingFlushOperations.containsKey(id)) {
+                        waitingFlushOperations.get(id).offer(operation);
+                    } else {
+                        PriorityQueue<ILSMIOOperation> q = new PriorityQueue<ILSMIOOperation>();
+                        q.offer(operation);
+                        waitingFlushOperations.put(id, q);
+                    }
+                } else {
+                    runningFlushOperations.put(id, operation);
+                    executor.submit(operation);
+                }
+            }
+        }
     }
 }
\ No newline at end of file
diff --git a/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMIOOperationTask.java b/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMIOOperationTask.java
new file mode 100644
index 0000000..9743afe
--- /dev/null
+++ b/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMIOOperationTask.java
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.hyracks.storage.am.lsm.common.impls;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.FutureTask;
+
+import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation;
+
+public class LSMIOOperationTask<T> extends FutureTask<T> {
+    private final ILSMIOOperation operation;
+
+    public LSMIOOperationTask(Callable<T> callable) {
+        super(callable);
+        this.operation = (ILSMIOOperation) callable;
+    }
+
+    public ILSMIOOperation getOperation() {
+        return operation;
+    }
+}
diff --git a/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMIndexSearchCursor.java b/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMIndexSearchCursor.java
index 2bc45a9..5a4699e 100644
--- a/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMIndexSearchCursor.java
+++ b/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMIndexSearchCursor.java
@@ -263,4 +263,9 @@
     protected int compare(MultiComparator cmp, ITupleReference tupleA, ITupleReference tupleB) {
         return cmp.compare(tupleA, tupleB);
     }
+    
+    @Override
+    public void markCurrentTupleAsUpdated() throws HyracksDataException {
+        throw new HyracksDataException("Updating tuples is not supported with this cursor.");
+    }
 }
\ No newline at end of file
diff --git a/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/VirtualBufferCache.java b/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/VirtualBufferCache.java
index bd3b278..7f804c1 100644
--- a/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/VirtualBufferCache.java
+++ b/hyracks/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/VirtualBufferCache.java
@@ -336,7 +336,7 @@
         }
 
         @Override
-        public void releaseWriteLatch() {
+        public void releaseWriteLatch(boolean markDirty) {
             latch.writeLock().unlock();
         }
 
diff --git a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndex.java b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndex.java
index 0600754..7b4ae42 100644
--- a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndex.java
+++ b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndex.java
@@ -438,7 +438,7 @@
         ioScheduler.scheduleOperation(new LSMInvertedIndexFlushOperation(
                 new LSMInvertedIndexAccessor(lsmHarness, opCtx), flushingComponent, componentFileRefs
                         .getInsertIndexFileReference(), componentFileRefs.getDeleteIndexFileReference(),
-                componentFileRefs.getBloomFilterFileReference(), callback));
+                componentFileRefs.getBloomFilterFileReference(), callback, fileManager.getBaseDir()));
     }
 
     @Override
@@ -458,7 +458,7 @@
                 .getInvIndex().createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
         BTreeAccessor memBTreeAccessor = memInvIndexAccessor.getBTreeAccessor();
         RangePredicate nullPred = new RangePredicate(null, null, true, true, null, null);
-        IIndexCursor scanCursor = memBTreeAccessor.createSearchCursor();
+        IIndexCursor scanCursor = memBTreeAccessor.createSearchCursor(false);
         memBTreeAccessor.search(scanCursor, nullPred);
 
         // Bulk load the disk inverted index from the in-memory inverted index.
@@ -498,7 +498,7 @@
             BTree diskDeletedKeysBTree = component.getDeletedKeysBTree();
 
             // Create a scan cursor on the deleted keys BTree underlying the in-memory inverted index.
-            IIndexCursor deletedKeysScanCursor = deletedKeysBTreeAccessor.createSearchCursor();
+            IIndexCursor deletedKeysScanCursor = deletedKeysBTreeAccessor.createSearchCursor(false);
             deletedKeysBTreeAccessor.search(deletedKeysScanCursor, nullPred);
 
             // Bulk load the deleted-keys BTree.
@@ -543,7 +543,7 @@
         ILSMIndexAccessorInternal accessor = new LSMInvertedIndexAccessor(lsmHarness, ctx);
         ioScheduler.scheduleOperation(new LSMInvertedIndexMergeOperation(accessor, mergingComponents, cursor,
                 relMergeFileRefs.getInsertIndexFileReference(), relMergeFileRefs.getDeleteIndexFileReference(),
-                relMergeFileRefs.getBloomFilterFileReference(), callback));
+                relMergeFileRefs.getBloomFilterFileReference(), callback, fileManager.getBaseDir()));
     }
 
     @Override
diff --git a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexAccessor.java b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexAccessor.java
index 7e34dfe..f76085a 100644
--- a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexAccessor.java
+++ b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexAccessor.java
@@ -71,7 +71,7 @@
         lsmHarness.search(ctx, cursor, searchPred);
     }
 
-    public IIndexCursor createSearchCursor() {
+    public IIndexCursor createSearchCursor(boolean exclusive) {
         return new LSMInvertedIndexSearchCursor();
     }
 
diff --git a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexDeletedKeysBTreeMergeCursor.java b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexDeletedKeysBTreeMergeCursor.java
index 3efaaba..9eb317d 100644
--- a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexDeletedKeysBTreeMergeCursor.java
+++ b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexDeletedKeysBTreeMergeCursor.java
@@ -54,7 +54,7 @@
         RangePredicate btreePredicate = new RangePredicate(null, null, true, true, keyCmp, keyCmp);
         ArrayList<IIndexAccessor> btreeAccessors = lsmInitialState.getDeletedKeysBTreeAccessors();
         for (int i = 0; i < numBTrees; i++) {
-            rangeCursors[i] = btreeAccessors.get(i).createSearchCursor();
+            rangeCursors[i] = btreeAccessors.get(i).createSearchCursor(false);
             btreeAccessors.get(i).search(rangeCursors[i], btreePredicate);
         }
         setPriorityQueueComparator();
diff --git a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexFlushOperation.java b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexFlushOperation.java
index 45433e7..beb7643 100644
--- a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexFlushOperation.java
+++ b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexFlushOperation.java
@@ -28,23 +28,25 @@
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperationCallback;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexAccessorInternal;
 
-public class LSMInvertedIndexFlushOperation implements ILSMIOOperation {
+public class LSMInvertedIndexFlushOperation implements ILSMIOOperation, Comparable<LSMInvertedIndexFlushOperation> {
     private final ILSMIndexAccessorInternal accessor;
     private final ILSMComponent flushingComponent;
     private final FileReference dictBTreeFlushTarget;
     private final FileReference deletedKeysBTreeFlushTarget;
     private final FileReference bloomFilterFlushTarget;
     private final ILSMIOOperationCallback callback;
+    private final String indexIdentifier;
 
     public LSMInvertedIndexFlushOperation(ILSMIndexAccessorInternal accessor, ILSMComponent flushingComponent,
             FileReference dictBTreeFlushTarget, FileReference deletedKeysBTreeFlushTarget,
-            FileReference bloomFilterFlushTarget, ILSMIOOperationCallback callback) {
+            FileReference bloomFilterFlushTarget, ILSMIOOperationCallback callback, String indexIdentifier) {
         this.accessor = accessor;
         this.flushingComponent = flushingComponent;
         this.dictBTreeFlushTarget = dictBTreeFlushTarget;
         this.deletedKeysBTreeFlushTarget = deletedKeysBTreeFlushTarget;
         this.bloomFilterFlushTarget = bloomFilterFlushTarget;
         this.callback = callback;
+        this.indexIdentifier = indexIdentifier;
     }
 
     @Override
@@ -88,4 +90,19 @@
     public ILSMComponent getFlushingComponent() {
         return flushingComponent;
     }
+
+    @Override
+    public String getIndexUniqueIdentifier() {
+        return indexIdentifier;
+    }
+
+    @Override
+    public LSMIOOpertionType getIOOpertionType() {
+        return LSMIOOpertionType.FLUSH;
+    }
+
+    @Override
+    public int compareTo(LSMInvertedIndexFlushOperation o) {
+        return dictBTreeFlushTarget.getFile().getName().compareTo(o.getDictBTreeFlushTarget().getFile().getName());
+    }
 }
diff --git a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexMergeOperation.java b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexMergeOperation.java
index 7cd921a..5a1e413 100644
--- a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexMergeOperation.java
+++ b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexMergeOperation.java
@@ -38,10 +38,11 @@
     private final FileReference deletedKeysBTreeMergeTarget;
     private final FileReference bloomFilterMergeTarget;
     private final ILSMIOOperationCallback callback;
+    private final String indexIdentifier;
 
     public LSMInvertedIndexMergeOperation(ILSMIndexAccessorInternal accessor, List<ILSMComponent> mergingComponents,
             IIndexCursor cursor, FileReference dictBTreeMergeTarget, FileReference deletedKeysBTreeMergeTarget,
-            FileReference bloomFilterMergeTarget, ILSMIOOperationCallback callback) {
+            FileReference bloomFilterMergeTarget, ILSMIOOperationCallback callback, String indexIdentifier) {
         this.accessor = accessor;
         this.mergingComponents = mergingComponents;
         this.cursor = cursor;
@@ -49,6 +50,7 @@
         this.deletedKeysBTreeMergeTarget = deletedKeysBTreeMergeTarget;
         this.bloomFilterMergeTarget = bloomFilterMergeTarget;
         this.callback = callback;
+        this.indexIdentifier = indexIdentifier;
     }
 
     @Override
@@ -103,4 +105,14 @@
     public List<ILSMComponent> getMergingComponents() {
         return mergingComponents;
     }
+
+    @Override
+    public String getIndexUniqueIdentifier() {
+        return indexIdentifier;
+    }
+
+    @Override
+    public LSMIOOpertionType getIOOpertionType() {
+        return LSMIOOpertionType.MERGE;
+    }
 }
\ No newline at end of file
diff --git a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexRangeSearchCursor.java b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexRangeSearchCursor.java
index a6ff07e..48e94eb 100644
--- a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexRangeSearchCursor.java
+++ b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexRangeSearchCursor.java
@@ -77,7 +77,7 @@
                 ILSMComponent component = operationalComponents.get(i);
                 if (component.getType() == LSMComponentType.MEMORY) {
                     // No need for a bloom filter for the in-memory BTree.
-                    deletedKeysBTreeCursors[i] = deletedKeysBTreeAccessors.get(i).createSearchCursor();
+                    deletedKeysBTreeCursors[i] = deletedKeysBTreeAccessors.get(i).createSearchCursor(false);
                 } else {
                     deletedKeysBTreeCursors[i] = new BloomFilterAwareBTreePointSearchCursor(
                             (IBTreeLeafFrame) lsmInitState.getgetDeletedKeysBTreeLeafFrameFactory().createFrame(),
diff --git a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexSearchCursor.java b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexSearchCursor.java
index 19acbfb..8ceedaf 100644
--- a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexSearchCursor.java
+++ b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexSearchCursor.java
@@ -76,7 +76,7 @@
             ILSMComponent component = operationalComponents.get(i);
             if (component.getType() == LSMComponentType.MEMORY) {
                 // No need for a bloom filter for the in-memory BTree.
-                deletedKeysBTreeCursors[i] = deletedKeysBTreeAccessors.get(i).createSearchCursor();
+                deletedKeysBTreeCursors[i] = deletedKeysBTreeAccessors.get(i).createSearchCursor(false);
             } else {
                 deletedKeysBTreeCursors[i] = new BloomFilterAwareBTreePointSearchCursor((IBTreeLeafFrame) lsmInitState
                         .getgetDeletedKeysBTreeLeafFrameFactory().createFrame(), false,
@@ -134,7 +134,7 @@
         while (accessorIndex < indexAccessors.size()) {
             // Current cursor has been exhausted, switch to next accessor/cursor.
             currentAccessor = indexAccessors.get(accessorIndex);
-            currentCursor = currentAccessor.createSearchCursor();
+            currentCursor = currentAccessor.createSearchCursor(false);
             try {
                 currentAccessor.search(currentCursor, searchPred);
             } catch (OccurrenceThresholdPanicException e) {
diff --git a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/InMemoryInvertedIndexAccessor.java b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/InMemoryInvertedIndexAccessor.java
index 7e9b483..ef8af32 100644
--- a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/InMemoryInvertedIndexAccessor.java
+++ b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/InMemoryInvertedIndexAccessor.java
@@ -65,7 +65,7 @@
     }
 
     @Override
-    public IIndexCursor createSearchCursor() {
+    public IIndexCursor createSearchCursor(boolean exclusive) {
         return new OnDiskInvertedIndexSearchCursor(searcher, index.getInvListTypeTraits().length);
     }
 
diff --git a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/InMemoryInvertedListCursor.java b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/InMemoryInvertedListCursor.java
index c742d0c..84e0fad 100644
--- a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/InMemoryInvertedListCursor.java
+++ b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/InMemoryInvertedListCursor.java
@@ -67,7 +67,7 @@
         // Avoid object creation if this.btreeAccessor == btreeAccessor.
         if (this.btreeAccessor != btreeAccessor) {
             this.btreeAccessor = btreeAccessor;
-            this.btreeCursor = btreeAccessor.createSearchCursor();
+            this.btreeCursor = btreeAccessor.createSearchCursor(false);
             this.countingCursor = btreeAccessor.createCountingSearchCursor();
             this.btreePred = btreePred;
             this.btreePred.setLowKeyComparator(tokenFieldsCmp);
diff --git a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndex.java b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndex.java
index 67d1796..d72e019 100644
--- a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndex.java
+++ b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndex.java
@@ -325,7 +325,7 @@
         }
 
         public void pinNextPage() throws HyracksDataException {
-            currentPage.releaseWriteLatch();
+            currentPage.releaseWriteLatch(true);
             bufferCache.unpin(currentPage);
             currentPageId++;
             currentPage = bufferCache.pin(BufferedFileHandle.getDiskPageId(fileId, currentPageId), true);
@@ -431,7 +431,7 @@
             btreeBulkloader.end();
 
             if (currentPage != null) {
-                currentPage.releaseWriteLatch();
+                currentPage.releaseWriteLatch(true);
                 bufferCache.unpin(currentPage);
             }
             invListsMaxPageId = currentPageId;
@@ -484,7 +484,7 @@
         }
 
         @Override
-        public IIndexCursor createSearchCursor() {
+        public IIndexCursor createSearchCursor(boolean exclusive) {
             return new OnDiskInvertedIndexSearchCursor(searcher, index.getInvListTypeTraits().length);
         }
 
@@ -565,6 +565,12 @@
         public ByteBuffer allocateFrame() {
             return ByteBuffer.allocate(FRAME_SIZE);
         }
+        
+        @Override
+        public void deallocateFrames(int frameCount) {
+            // TODO Auto-generated method stub
+            
+        }
     }
 
     @Override
@@ -584,7 +590,7 @@
         // Scan the btree and validate the order of elements in each inverted-list.
         IIndexAccessor btreeAccessor = btree.createAccessor(NoOpOperationCallback.INSTANCE,
                 NoOpOperationCallback.INSTANCE);
-        IIndexCursor btreeCursor = btreeAccessor.createSearchCursor();
+        IIndexCursor btreeCursor = btreeAccessor.createSearchCursor(false);
         MultiComparator btreeCmp = MultiComparator.createIgnoreFieldLength(btree.getComparatorFactories());
         RangePredicate rangePred = new RangePredicate(null, null, true, true, btreeCmp, btreeCmp);
         int[] fieldPermutation = new int[tokenTypeTraits.length];
diff --git a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexOpContext.java b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexOpContext.java
index 5c47601..509409f 100644
--- a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexOpContext.java
+++ b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexOpContext.java
@@ -36,7 +36,7 @@
     public OnDiskInvertedIndexOpContext(BTree btree) {
         // TODO: Ignore opcallbacks for now.
         btreeAccessor = btree.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
-        btreeCursor = btreeAccessor.createSearchCursor();
+        btreeCursor = btreeAccessor.createSearchCursor(false);
         searchCmp = MultiComparator.createIgnoreFieldLength(btree.getComparatorFactories());
         if (btree.getComparatorFactories().length > 1) {
             prefixSearchCmp = MultiComparator.create(btree.getComparatorFactories(), 0, 1);
diff --git a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexRangeSearchCursor.java b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexRangeSearchCursor.java
index defe29c..9cb7231 100644
--- a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexRangeSearchCursor.java
+++ b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexRangeSearchCursor.java
@@ -59,7 +59,7 @@
             fieldPermutation[i] = i;
         }
         tokenTuple = new PermutingTupleReference(fieldPermutation);
-        btreeCursor = btreeAccessor.createSearchCursor();
+        btreeCursor = btreeAccessor.createSearchCursor(false);
         concatTuple = new ConcatenatingTupleReference(2);
         invListCursor = invIndex.createInvertedListCursor();
         unpinNeeded = false;
diff --git a/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTree.java b/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTree.java
index 662aa02..95d1a11 100644
--- a/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTree.java
+++ b/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTree.java
@@ -177,7 +177,7 @@
         LSMRTreeAccessor accessor = new LSMRTreeAccessor(lsmHarness, rctx);
         ioScheduler.scheduleOperation(new LSMRTreeFlushOperation(accessor, flushingComponent, componentFileRefs
                 .getInsertIndexFileReference(), componentFileRefs.getDeleteIndexFileReference(), componentFileRefs
-                .getBloomFilterFileReference(), callback));
+                .getBloomFilterFileReference(), callback, fileManager.getBaseDir()));
     }
 
     @Override
@@ -191,7 +191,7 @@
         // scan the memory RTree
         ITreeIndexAccessor memRTreeAccessor = flushingComponent.getRTree().createAccessor(
                 NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
-        RTreeSearchCursor rtreeScanCursor = (RTreeSearchCursor) memRTreeAccessor.createSearchCursor();
+        RTreeSearchCursor rtreeScanCursor = (RTreeSearchCursor) memRTreeAccessor.createSearchCursor(false);
         SearchPredicate rtreeNullPredicate = new SearchPredicate(null, null);
         memRTreeAccessor.search(rtreeScanCursor, rtreeNullPredicate);
         LSMRTreeDiskComponent component = createDiskComponent(componentFactory, flushOp.getRTreeFlushTarget(),
@@ -258,7 +258,7 @@
             BloomFilterSpecification bloomFilterSpec = BloomCalculations.computeBloomSpec(maxBucketsPerElement,
                     bloomFilterFalsePositiveRate);
 
-            IIndexCursor btreeScanCursor = memBTreeAccessor.createSearchCursor();
+            IIndexCursor btreeScanCursor = memBTreeAccessor.createSearchCursor(false);
             memBTreeAccessor.search(btreeScanCursor, btreeNullPredicate);
             BTree diskBTree = component.getBTree();
 
@@ -295,7 +295,8 @@
         ILSMIndexAccessorInternal accessor = new LSMRTreeAccessor(lsmHarness, rctx);
         ioScheduler.scheduleOperation(new LSMRTreeMergeOperation((ILSMIndexAccessorInternal) accessor,
                 mergingComponents, cursor, relMergeFileRefs.getInsertIndexFileReference(), relMergeFileRefs
-                        .getDeleteIndexFileReference(), relMergeFileRefs.getBloomFilterFileReference(), callback));
+                        .getDeleteIndexFileReference(), relMergeFileRefs.getBloomFilterFileReference(), callback,
+                fileManager.getBaseDir()));
     }
 
     @Override
@@ -359,7 +360,7 @@
         }
 
         @Override
-        public ITreeIndexCursor createSearchCursor() {
+        public ITreeIndexCursor createSearchCursor(boolean exclusive) {
             return new LSMRTreeSearchCursor(ctx);
         }
 
diff --git a/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeAbstractCursor.java b/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeAbstractCursor.java
index 4e322d4..32f3174 100644
--- a/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeAbstractCursor.java
+++ b/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeAbstractCursor.java
@@ -163,4 +163,8 @@
         return false;
     }
 
+    @Override
+    public void markCurrentTupleAsUpdated() throws HyracksDataException {
+        throw new HyracksDataException("Updating tuples is not supported with this cursor.");
+    }
 }
\ No newline at end of file
diff --git a/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeFlushOperation.java b/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeFlushOperation.java
index 18d7a7e..0d40eb4 100644
--- a/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeFlushOperation.java
+++ b/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeFlushOperation.java
@@ -27,7 +27,7 @@
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperationCallback;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexAccessorInternal;
 
-public class LSMRTreeFlushOperation implements ILSMIOOperation {
+public class LSMRTreeFlushOperation implements ILSMIOOperation, Comparable<LSMRTreeFlushOperation> {
 
     private final ILSMIndexAccessorInternal accessor;
     private final ILSMComponent flushingComponent;
@@ -35,16 +35,18 @@
     private final FileReference btreeFlushTarget;
     private final FileReference bloomFilterFlushTarget;
     private final ILSMIOOperationCallback callback;
+    private final String indexIdentifier;
 
     public LSMRTreeFlushOperation(ILSMIndexAccessorInternal accessor, ILSMComponent flushingComponent,
             FileReference rtreeFlushTarget, FileReference btreeFlushTarget, FileReference bloomFilterFlushTarget,
-            ILSMIOOperationCallback callback) {
+            ILSMIOOperationCallback callback, String indexIdentifier) {
         this.accessor = accessor;
         this.flushingComponent = flushingComponent;
         this.rtreeFlushTarget = rtreeFlushTarget;
         this.btreeFlushTarget = btreeFlushTarget;
         this.bloomFilterFlushTarget = bloomFilterFlushTarget;
         this.callback = callback;
+        this.indexIdentifier = indexIdentifier;
     }
 
     @Override
@@ -89,4 +91,19 @@
     public ILSMComponent getFlushingComponent() {
         return flushingComponent;
     }
+
+    @Override
+    public String getIndexUniqueIdentifier() {
+        return indexIdentifier;
+    }
+
+    @Override
+    public LSMIOOpertionType getIOOpertionType() {
+        return LSMIOOpertionType.FLUSH;
+    }
+
+    @Override
+    public int compareTo(LSMRTreeFlushOperation o) {
+        return rtreeFlushTarget.getFile().getName().compareTo(o.getRTreeFlushTarget().getFile().getName());
+    }
 }
diff --git a/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeMergeOperation.java b/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeMergeOperation.java
index da7a2fb..ddf3ebf 100644
--- a/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeMergeOperation.java
+++ b/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeMergeOperation.java
@@ -36,10 +36,11 @@
     private final FileReference btreeMergeTarget;
     private final FileReference bloomFilterMergeTarget;
     private final ILSMIOOperationCallback callback;
+    private final String indexIdentifier;
 
     public LSMRTreeMergeOperation(ILSMIndexAccessorInternal accessor, List<ILSMComponent> mergingComponents,
             ITreeIndexCursor cursor, FileReference rtreeMergeTarget, FileReference btreeMergeTarget,
-            FileReference bloomFilterMergeTarget, ILSMIOOperationCallback callback) {
+            FileReference bloomFilterMergeTarget, ILSMIOOperationCallback callback, String indexIdentifier) {
         this.accessor = accessor;
         this.mergingComponents = mergingComponents;
         this.cursor = cursor;
@@ -47,6 +48,7 @@
         this.btreeMergeTarget = btreeMergeTarget;
         this.bloomFilterMergeTarget = bloomFilterMergeTarget;
         this.callback = callback;
+        this.indexIdentifier = indexIdentifier;
     }
 
     @Override
@@ -104,4 +106,14 @@
     public List<ILSMComponent> getMergingComponents() {
         return mergingComponents;
     }
+
+    @Override
+    public String getIndexUniqueIdentifier() {
+        return indexIdentifier;
+    }
+
+    @Override
+    public LSMIOOpertionType getIOOpertionType() {
+        return LSMIOOpertionType.MERGE;
+    }
 }
diff --git a/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeWithAntiMatterTuples.java b/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeWithAntiMatterTuples.java
index ec66a39..71d83f2 100644
--- a/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeWithAntiMatterTuples.java
+++ b/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeWithAntiMatterTuples.java
@@ -155,7 +155,7 @@
         opCtx.getComponentHolder().add(flushingComponent);
         ILSMIndexAccessorInternal accessor = new LSMRTreeWithAntiMatterTuplesAccessor(lsmHarness, opCtx);
         ioScheduler.scheduleOperation(new LSMRTreeFlushOperation(accessor, flushingComponent, relFlushFileRefs
-                .getInsertIndexFileReference(), null, null, callback));
+                .getInsertIndexFileReference(), null, null, callback, fileManager.getBaseDir()));
     }
 
     @Override
@@ -167,7 +167,7 @@
         LSMRTreeMemoryComponent flushingComponent = (LSMRTreeMemoryComponent) flushOp.getFlushingComponent();
         ITreeIndexAccessor memRTreeAccessor = flushingComponent.getRTree().createAccessor(
                 NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
-        RTreeSearchCursor rtreeScanCursor = (RTreeSearchCursor) memRTreeAccessor.createSearchCursor();
+        RTreeSearchCursor rtreeScanCursor = (RTreeSearchCursor) memRTreeAccessor.createSearchCursor(false);
         SearchPredicate rtreeNullPredicate = new SearchPredicate(null, null);
         memRTreeAccessor.search(rtreeScanCursor, rtreeNullPredicate);
         LSMRTreeDiskComponent component = createDiskComponent(componentFactory, flushOp.getRTreeFlushTarget(), null,
@@ -177,7 +177,7 @@
         // scan the memory BTree
         ITreeIndexAccessor memBTreeAccessor = flushingComponent.getBTree().createAccessor(
                 NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
-        BTreeRangeSearchCursor btreeScanCursor = (BTreeRangeSearchCursor) memBTreeAccessor.createSearchCursor();
+        BTreeRangeSearchCursor btreeScanCursor = (BTreeRangeSearchCursor) memBTreeAccessor.createSearchCursor(false);
         RangePredicate btreeNullPredicate = new RangePredicate(null, null, true, true, null, null);
         memBTreeAccessor.search(btreeScanCursor, btreeNullPredicate);
 
@@ -256,7 +256,7 @@
         LSMComponentFileReferences relMergeFileRefs = getMergeTargetFileName(mergingComponents);
         ILSMIndexAccessorInternal accessor = new LSMRTreeWithAntiMatterTuplesAccessor(lsmHarness, rctx);
         ioScheduler.scheduleOperation(new LSMRTreeMergeOperation(accessor, mergingComponents, cursor, relMergeFileRefs
-                .getInsertIndexFileReference(), null, null, callback));
+                .getInsertIndexFileReference(), null, null, callback, fileManager.getBaseDir()));
     }
 
     @Override
@@ -298,7 +298,7 @@
         }
 
         @Override
-        public ITreeIndexCursor createSearchCursor() {
+        public ITreeIndexCursor createSearchCursor(boolean exclusive) {
             return new LSMRTreeWithAntiMatterTuplesSearchCursor(ctx);
         }
 
diff --git a/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeWithAntiMatterTuplesFlushCursor.java b/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeWithAntiMatterTuplesFlushCursor.java
index 0dd2281..aa3fad8 100644
--- a/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeWithAntiMatterTuplesFlushCursor.java
+++ b/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeWithAntiMatterTuplesFlushCursor.java
@@ -145,20 +145,21 @@
 
     @Override
     public void setBufferCache(IBufferCache bufferCache) {
-        // TODO Auto-generated method stub
 
     }
 
     @Override
     public void setFileId(int fileId) {
-        // TODO Auto-generated method stub
 
     }
 
     @Override
     public boolean exclusiveLatchNodes() {
-        // TODO Auto-generated method stub
         return false;
     }
 
+    @Override
+    public void markCurrentTupleAsUpdated() throws HyracksDataException {
+        throw new HyracksDataException("Updating tuples is not supported with this cursor.");
+    }
 }
diff --git a/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/TreeTupleSorter.java b/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/TreeTupleSorter.java
index 03d9043..7946529 100644
--- a/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/TreeTupleSorter.java
+++ b/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/TreeTupleSorter.java
@@ -222,4 +222,8 @@
         return false;
     }
 
+    @Override
+    public void markCurrentTupleAsUpdated() throws HyracksDataException {
+        throw new HyracksDataException("Updating tuples is not supported with this cursor.");
+    }
 }
\ No newline at end of file
diff --git a/hyracks/hyracks-storage-am-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/impls/RTree.java b/hyracks/hyracks-storage-am-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/impls/RTree.java
index 7bb3583..266686f 100644
--- a/hyracks/hyracks-storage-am-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/impls/RTree.java
+++ b/hyracks/hyracks-storage-am-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/impls/RTree.java
@@ -201,7 +201,7 @@
                 ICachedPage node = ctx.LSNUpdates.get(i);
                 ctx.interiorFrame.setPage(node);
                 ctx.interiorFrame.setPageLsn(incrementGlobalNsn());
-                node.releaseWriteLatch();
+                node.releaseWriteLatch(true);
                 bufferCache.unpin(node);
             }
         }
@@ -228,7 +228,7 @@
                         writeLatched = true;
 
                         if (!ctx.interiorFrame.isLeaf()) {
-                            node.releaseWriteLatch();
+                            node.releaseWriteLatch(true);
                             writeLatched = false;
                             bufferCache.unpin(node);
                             continue;
@@ -246,7 +246,7 @@
                     // Concurrent split detected, go back to parent and
                     // re-choose the best child
                     if (writeLatched) {
-                        node.releaseWriteLatch();
+                        node.releaseWriteLatch(true);
                         writeLatched = false;
                         bufferCache.unpin(node);
                     } else {
@@ -294,7 +294,7 @@
                         // already pointing to the best child
                         ctx.interiorFrame.enlarge(ctx.getTuple(), ctx.cmp);
 
-                        node.releaseWriteLatch();
+                        node.releaseWriteLatch(true);
                         writeLatched = false;
                         bufferCache.unpin(node);
                     } else {
@@ -303,7 +303,7 @@
                             readLatched = false;
                             bufferCache.unpin(node);
                         } else if (writeLatched) {
-                            node.releaseWriteLatch();
+                            node.releaseWriteLatch(true);
                             writeLatched = false;
                             bufferCache.unpin(node);
                         }
@@ -324,7 +324,7 @@
                     readLatched = false;
                     bufferCache.unpin(node);
                 } else if (writeLatched) {
-                    node.releaseWriteLatch();
+                    node.releaseWriteLatch(true);
                     writeLatched = false;
                     bufferCache.unpin(node);
                 }
@@ -359,7 +359,7 @@
                     } else if (isLeaf) {
                         // In case of a crash, we un-latch the interior node
                         // inside updateParentForInsert.
-                        node.releaseWriteLatch();
+                        node.releaseWriteLatch(true);
                         bufferCache.unpin(node);
                     }
                 }
@@ -384,7 +384,7 @@
                     } else if (isLeaf) {
                         // In case of a crash, we un-latch the interior node
                         // inside updateParentForInsert.
-                        node.releaseWriteLatch();
+                        node.releaseWriteLatch(true);
                         bufferCache.unpin(node);
                     }
                 }
@@ -424,12 +424,12 @@
                     } else if (isLeaf) {
                         // In case of a crash, we un-latch the interior node
                         // inside updateParentForInsert.
-                        node.releaseWriteLatch();
+                        node.releaseWriteLatch(true);
                         bufferCache.unpin(node);
-                        rightNode.releaseWriteLatch();
+                        rightNode.releaseWriteLatch(true);
                         bufferCache.unpin(rightNode);
                     } else {
-                        rightNode.releaseWriteLatch();
+                        rightNode.releaseWriteLatch(true);
                         bufferCache.unpin(rightNode);
                     }
 
@@ -469,16 +469,16 @@
                         } else if (isLeaf) {
                             // In case of a crash, we un-latch the interior node
                             // inside updateParentForInsert.
-                            node.releaseWriteLatch();
+                            node.releaseWriteLatch(true);
                             bufferCache.unpin(node);
-                            rightNode.releaseWriteLatch();
+                            rightNode.releaseWriteLatch(true);
                             bufferCache.unpin(rightNode);
-                            newLeftNode.releaseWriteLatch();
+                            newLeftNode.releaseWriteLatch(true);
                             bufferCache.unpin(newLeftNode);
                         } else {
-                            rightNode.releaseWriteLatch();
+                            rightNode.releaseWriteLatch(true);
                             bufferCache.unpin(rightNode);
-                            newLeftNode.releaseWriteLatch();
+                            newLeftNode.releaseWriteLatch(true);
                             bufferCache.unpin(newLeftNode);
                         }
                     }
@@ -508,7 +508,7 @@
                         break;
                     }
                     int rightPage = ctx.interiorFrame.getRightPage();
-                    parentNode.releaseWriteLatch();
+                    parentNode.releaseWriteLatch(true);
                     writeLatched = false;
                     bufferCache.unpin(parentNode);
 
@@ -529,7 +529,7 @@
                     ctx.interiorFrame.adjustKey(ctx.splitKey.getLeftTuple(), -1, ctx.cmp);
                 } catch (TreeIndexException e) {
                     if (writeLatched) {
-                        parentNode.releaseWriteLatch();
+                        parentNode.releaseWriteLatch(true);
                         writeLatched = false;
                         bufferCache.unpin(parentNode);
                     }
@@ -544,7 +544,7 @@
         } finally {
             if (!succeeded) {
                 if (writeLatched) {
-                    parentNode.releaseWriteLatch();
+                    parentNode.releaseWriteLatch(true);
                     writeLatched = false;
                     bufferCache.unpin(parentNode);
                 }
@@ -634,7 +634,7 @@
             try {
                 deleteTuple(tupleIndex, ctx);
             } finally {
-                ctx.leafFrame.getPage().releaseWriteLatch();
+                ctx.leafFrame.getPage().releaseWriteLatch(true);
                 bufferCache.unpin(ctx.leafFrame.getPage());
             }
         }
@@ -694,7 +694,7 @@
                         if (!ctx.leafFrame.isLeaf()) {
                             ctx.pathList.add(pageId, -1, -1);
 
-                            node.releaseWriteLatch();
+                            node.releaseWriteLatch(true);
                             writeLatched = false;
                             bufferCache.unpin(node);
                             continue;
@@ -707,7 +707,7 @@
                             if (tupleIndex == -1) {
                                 ctx.pathList.add(pageId, parentLsn, -1);
 
-                                node.releaseWriteLatch();
+                                node.releaseWriteLatch(true);
                                 writeLatched = false;
                                 bufferCache.unpin(node);
                                 continue;
@@ -732,7 +732,7 @@
                     readLatched = false;
                     bufferCache.unpin(node);
                 } else if (writeLatched) {
-                    node.releaseWriteLatch();
+                    node.releaseWriteLatch(true);
                     writeLatched = false;
                     bufferCache.unpin(node);
                 }
@@ -825,7 +825,7 @@
         }
 
         @Override
-        public ITreeIndexCursor createSearchCursor() {
+        public ITreeIndexCursor createSearchCursor(boolean exclusive) {
             return new RTreeSearchCursor((IRTreeInteriorFrame) interiorFrameFactory.createFrame(),
                     (IRTreeLeafFrame) leafFrameFactory.createFrame());
         }
@@ -907,7 +907,7 @@
 
                     leafFrontier.pageId = freePageManager.getFreePage(metaFrame);
 
-                    leafFrontier.page.releaseWriteLatch();
+                    leafFrontier.page.releaseWriteLatch(true);
                     bufferCache.unpin(leafFrontier.page);
 
                     leafFrontier.page = bufferCache.pin(BufferedFileHandle.getDiskPageId(fileId, leafFrontier.pageId),
@@ -974,7 +974,7 @@
                 propagateBulk(level + 1, toRoot);
                 propagated = true;
 
-                frontier.page.releaseWriteLatch();
+                frontier.page.releaseWriteLatch(true);
                 bufferCache.unpin(frontier.page);
                 frontier.pageId = freePageManager.getFreePage(metaFrame);
 
diff --git a/hyracks/hyracks-storage-am-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/impls/RTreeSearchCursor.java b/hyracks/hyracks-storage-am-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/impls/RTreeSearchCursor.java
index c71b3eb..ab82f08 100644
--- a/hyracks/hyracks-storage-am-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/impls/RTreeSearchCursor.java
+++ b/hyracks/hyracks-storage-am-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/impls/RTreeSearchCursor.java
@@ -252,4 +252,9 @@
     public boolean exclusiveLatchNodes() {
         return false;
     }
+    
+    @Override
+    public void markCurrentTupleAsUpdated() throws HyracksDataException {
+        throw new HyracksDataException("Updating tuples is not supported with this cursor.");
+    }
 }
\ No newline at end of file
diff --git a/hyracks/hyracks-storage-common/src/main/java/edu/uci/ics/hyracks/storage/common/buffercache/BufferCache.java b/hyracks/hyracks-storage-common/src/main/java/edu/uci/ics/hyracks/storage/common/buffercache/BufferCache.java
index 2992dfe..4162dc2 100644
--- a/hyracks/hyracks-storage-common/src/main/java/edu/uci/ics/hyracks/storage/common/buffercache/BufferCache.java
+++ b/hyracks/hyracks-storage-common/src/main/java/edu/uci/ics/hyracks/storage/common/buffercache/BufferCache.java
@@ -474,18 +474,9 @@
             latch.readLock().lock();
         }
 
-        private void acquireWriteLatch(boolean markDirty) {
-            latch.writeLock().lock();
-            if (markDirty) {
-                if (dirty.compareAndSet(false, true)) {
-                    pinCount.incrementAndGet();
-                }
-            }
-        }
-
         @Override
         public void acquireWriteLatch() {
-            acquireWriteLatch(true);
+            latch.writeLock().lock();
         }
 
         @Override
@@ -494,7 +485,12 @@
         }
 
         @Override
-        public void releaseWriteLatch() {
+        public void releaseWriteLatch(boolean markDirty) {
+            if (markDirty) {
+                if (dirty.compareAndSet(false, true)) {
+                    pinCount.incrementAndGet();
+                }
+            }
             latch.writeLock().unlock();
         }
     }
diff --git a/hyracks/hyracks-storage-common/src/main/java/edu/uci/ics/hyracks/storage/common/buffercache/ICachedPage.java b/hyracks/hyracks-storage-common/src/main/java/edu/uci/ics/hyracks/storage/common/buffercache/ICachedPage.java
index b5bf3bb..6c86597 100644
--- a/hyracks/hyracks-storage-common/src/main/java/edu/uci/ics/hyracks/storage/common/buffercache/ICachedPage.java
+++ b/hyracks/hyracks-storage-common/src/main/java/edu/uci/ics/hyracks/storage/common/buffercache/ICachedPage.java
@@ -25,5 +25,5 @@
 
     public void acquireWriteLatch();
 
-    public void releaseWriteLatch();
+    public void releaseWriteLatch(boolean markDirty);
 }
\ No newline at end of file
diff --git a/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/AbstractSearchOperationCallbackTest.java b/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/AbstractSearchOperationCallbackTest.java
index 02ce7f1..4c158ce 100644
--- a/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/AbstractSearchOperationCallbackTest.java
+++ b/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/AbstractSearchOperationCallbackTest.java
@@ -88,7 +88,7 @@
         public SearchTask() throws HyracksDataException {
             this.cb = new SynchronizingSearchOperationCallback();
             this.accessor = index.createAccessor(NoOpOperationCallback.INSTANCE, cb);
-            this.cursor = accessor.createSearchCursor();
+            this.cursor = accessor.createSearchCursor(false);
             this.predicate = new RangePredicate();
             this.builder = new ArrayTupleBuilder(NUM_KEY_FIELDS);
             this.tuple = new ArrayTupleReference();
diff --git a/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexExamplesTest.java b/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexExamplesTest.java
index 0a70185..f814829 100644
--- a/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexExamplesTest.java
+++ b/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexExamplesTest.java
@@ -735,7 +735,7 @@
         if (LOGGER.isLoggable(Level.INFO)) {
             LOGGER.info("Ordered Scan:");
         }
-        IIndexCursor scanCursor = (IIndexCursor) indexAccessor.createSearchCursor();
+        IIndexCursor scanCursor = (IIndexCursor) indexAccessor.createSearchCursor(false);
         RangePredicate nullPred = new RangePredicate(null, null, true, true, null, null);
         indexAccessor.search(scanCursor, nullPred);
         try {
@@ -795,7 +795,7 @@
             String highKeyString = TupleUtils.printTuple(highKey, fieldSerdes);
             LOGGER.info("Range-Search in: [ " + lowKeyString + ", " + highKeyString + "]");
         }
-        ITreeIndexCursor rangeCursor = (ITreeIndexCursor) indexAccessor.createSearchCursor();
+        ITreeIndexCursor rangeCursor = (ITreeIndexCursor) indexAccessor.createSearchCursor(false);
         MultiComparator lowKeySearchCmp = BTreeUtils.getSearchMultiComparator(cmpFactories, lowKey);
         MultiComparator highKeySearchCmp = BTreeUtils.getSearchMultiComparator(cmpFactories, highKey);
         RangePredicate rangePred = new RangePredicate(lowKey, highKey, true, true, lowKeySearchCmp, highKeySearchCmp);
diff --git a/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexSortedInsertTest.java b/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexSortedInsertTest.java
new file mode 100644
index 0000000..e8b83e8
--- /dev/null
+++ b/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexSortedInsertTest.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.hyracks.storage.am.btree;
+
+import edu.uci.ics.hyracks.api.dataflow.value.ISerializerDeserializer;
+import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
+import edu.uci.ics.hyracks.dataflow.common.data.marshalling.IntegerSerializerDeserializer;
+import edu.uci.ics.hyracks.dataflow.common.data.marshalling.UTF8StringSerializerDeserializer;
+import edu.uci.ics.hyracks.storage.am.btree.frames.BTreeLeafFrameType;
+
+/**
+ * Tests the BTree insert operation with sorted stream of strings and integer fields using
+ * various numbers of key and payload fields.
+ * Each tests first fills a BTree with sorted generated tuples. We compare the
+ * following operations against expected results: 1. Point searches for all
+ * tuples. 2. Ordered scan. 3. Disk-order scan. 4. Range search (and prefix
+ * search for composite keys).
+ */
+@SuppressWarnings("rawtypes")
+public abstract class OrderedIndexSortedInsertTest extends OrderedIndexTestDriver {
+
+    private final OrderedIndexTestUtils orderedIndexTestUtils;
+
+    public OrderedIndexSortedInsertTest(BTreeLeafFrameType[] leafFrameTypesToTest) {
+        super(leafFrameTypesToTest);
+        this.orderedIndexTestUtils = new OrderedIndexTestUtils();
+    }
+
+    @Override
+    protected void runTest(ISerializerDeserializer[] fieldSerdes, int numKeys, BTreeLeafFrameType leafType,
+            ITupleReference lowKey, ITupleReference highKey, ITupleReference prefixLowKey, ITupleReference prefixHighKey)
+            throws Exception {
+        OrderedIndexTestContext ctx = createTestContext(fieldSerdes, numKeys, leafType);
+        ctx.getIndex().create();
+        ctx.getIndex().activate();
+        // We assume all fieldSerdes are of the same type. Check the first one
+        // to determine which field types to generate.
+        if (fieldSerdes[0] instanceof IntegerSerializerDeserializer) {
+            orderedIndexTestUtils.insertSortedIntTuples(ctx, numTuplesToInsert, getRandom());
+        } else if (fieldSerdes[0] instanceof UTF8StringSerializerDeserializer) {
+            orderedIndexTestUtils.insertSortedStringTuples(ctx, numTuplesToInsert, getRandom());
+        }
+
+        orderedIndexTestUtils.checkPointSearches(ctx);
+        orderedIndexTestUtils.checkScan(ctx);
+        orderedIndexTestUtils.checkDiskOrderScan(ctx);
+
+        orderedIndexTestUtils.checkRangeSearch(ctx, lowKey, highKey, true, true);
+        if (prefixLowKey != null && prefixHighKey != null) {
+            orderedIndexTestUtils.checkRangeSearch(ctx, prefixLowKey, prefixHighKey, true, true);
+        }
+
+        ctx.getIndex().validate();
+        ctx.getIndex().deactivate();
+        ctx.getIndex().destroy();
+    }
+
+    @Override
+    protected String getTestOpName() {
+        return "Insert-Sorted";
+    }
+}
diff --git a/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexTestUtils.java b/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexTestUtils.java
index 9de217b..a2a4ba8 100644
--- a/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexTestUtils.java
+++ b/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexTestUtils.java
@@ -43,6 +43,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexCursor;
 import edu.uci.ics.hyracks.storage.am.common.api.ISearchPredicate;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexCursor;
+import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
 import edu.uci.ics.hyracks.storage.am.common.exceptions.TreeIndexDuplicateKeyException;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
 
@@ -93,7 +94,7 @@
         }
         MultiComparator lowKeyCmp = BTreeUtils.getSearchMultiComparator(ctx.getComparatorFactories(), lowKey);
         MultiComparator highKeyCmp = BTreeUtils.getSearchMultiComparator(ctx.getComparatorFactories(), highKey);
-        IIndexCursor searchCursor = ctx.getIndexAccessor().createSearchCursor();
+        IIndexCursor searchCursor = ctx.getIndexAccessor().createSearchCursor(false);
         RangePredicate rangePred = new RangePredicate(lowKey, highKey, lowKeyInclusive, highKeyInclusive, lowKeyCmp,
                 highKeyCmp);
         ctx.getIndexAccessor().search(searchCursor, rangePred);
@@ -140,7 +141,7 @@
             LOGGER.info("Testing Point Searches On All Expected Keys.");
         }
         OrderedIndexTestContext ctx = (OrderedIndexTestContext) ictx;
-        IIndexCursor searchCursor = ctx.getIndexAccessor().createSearchCursor();
+        IIndexCursor searchCursor = ctx.getIndexAccessor().createSearchCursor(false);
 
         ArrayTupleBuilder lowKeyBuilder = new ArrayTupleBuilder(ctx.getKeyFieldCount());
         ArrayTupleReference lowKey = new ArrayTupleReference();
@@ -180,6 +181,79 @@
     }
 
     @SuppressWarnings("unchecked")
+    public void insertSortedIntTuples(IIndexTestContext ctx, int numTuples, Random rnd) throws Exception {
+        int fieldCount = ctx.getFieldCount();
+        int numKeyFields = ctx.getKeyFieldCount();
+        int[] fieldValues = new int[ctx.getFieldCount()];
+        int maxValue = (int) Math.ceil(Math.pow(numTuples, 1.0 / (double) numKeyFields));
+        Collection<CheckTuple> tmpCheckTuples = createCheckTuplesCollection();
+        for (int i = 0; i < numTuples; i++) {
+            // Set keys.
+            setIntKeyFields(fieldValues, numKeyFields, maxValue, rnd);
+            // Set values.
+            setIntPayloadFields(fieldValues, numKeyFields, fieldCount);
+
+            // Set expected values. (We also use these as the pre-sorted stream
+            // for ordered indexes bulk loading).
+            ctx.insertCheckTuple(createIntCheckTuple(fieldValues, ctx.getKeyFieldCount()), tmpCheckTuples);
+        }
+        insertCheckTuples(ctx, tmpCheckTuples);
+
+        // Add tmpCheckTuples to ctx check tuples for comparing searches.
+        for (CheckTuple checkTuple : tmpCheckTuples) {
+            ctx.insertCheckTuple(checkTuple, ctx.getCheckTuples());
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    public void insertSortedStringTuples(IIndexTestContext ctx, int numTuples, Random rnd) throws Exception {
+        int fieldCount = ctx.getFieldCount();
+        int numKeyFields = ctx.getKeyFieldCount();
+        String[] fieldValues = new String[fieldCount];
+        TreeSet<CheckTuple> tmpCheckTuples = new TreeSet<CheckTuple>();
+        for (int i = 0; i < numTuples; i++) {
+            // Set keys.
+            for (int j = 0; j < numKeyFields; j++) {
+                int length = (Math.abs(rnd.nextInt()) % 10) + 1;
+                fieldValues[j] = getRandomString(length, rnd);
+            }
+            // Set values.
+            for (int j = numKeyFields; j < fieldCount; j++) {
+                fieldValues[j] = getRandomString(5, rnd);
+            }
+            // Set expected values. We also use these as the pre-sorted stream
+            // for bulk loading.
+            ctx.insertCheckTuple(createStringCheckTuple(fieldValues, ctx.getKeyFieldCount()), tmpCheckTuples);
+        }
+        insertCheckTuples(ctx, tmpCheckTuples);
+
+        // Add tmpCheckTuples to ctx check tuples for comparing searches.
+        for (CheckTuple checkTuple : tmpCheckTuples) {
+            ctx.insertCheckTuple(checkTuple, ctx.getCheckTuples());
+        }
+    }
+
+    public static void insertCheckTuples(IIndexTestContext ctx, Collection<CheckTuple> checkTuples)
+            throws HyracksDataException, IndexException {
+        int fieldCount = ctx.getFieldCount();
+        int numTuples = checkTuples.size();
+        ArrayTupleBuilder tupleBuilder = new ArrayTupleBuilder(fieldCount);
+        ArrayTupleReference tuple = new ArrayTupleReference();
+
+        int c = 1;
+        for (CheckTuple checkTuple : checkTuples) {
+            if (LOGGER.isLoggable(Level.INFO)) {
+                if (c % (numTuples / 10) == 0) {
+                    LOGGER.info("Inserting Tuple " + c + "/" + numTuples);
+                }
+            }
+            createTupleFromCheckTuple(checkTuple, tupleBuilder, tuple, ctx.getFieldSerdes());
+            ctx.getIndexAccessor().insert(tuple);
+            c++;
+        }
+    }
+
+    @SuppressWarnings("unchecked")
     public void insertStringTuples(IIndexTestContext ctx, int numTuples, Random rnd) throws Exception {
         int fieldCount = ctx.getFieldCount();
         int numKeyFields = ctx.getKeyFieldCount();
diff --git a/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TreeIndexTestUtils.java b/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TreeIndexTestUtils.java
index b5742b5..2919805 100644
--- a/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TreeIndexTestUtils.java
+++ b/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TreeIndexTestUtils.java
@@ -98,7 +98,7 @@
         if (LOGGER.isLoggable(Level.INFO)) {
             LOGGER.info("Testing Scan.");
         }
-        ITreeIndexCursor scanCursor = (ITreeIndexCursor) ctx.getIndexAccessor().createSearchCursor();
+        ITreeIndexCursor scanCursor = (ITreeIndexCursor) ctx.getIndexAccessor().createSearchCursor(false);
         ISearchPredicate nullPred = createNullSearchPredicate();
         ctx.getIndexAccessor().search(scanCursor, nullPred);
         Iterator<CheckTuple> checkIter = ctx.getCheckTuples().iterator();
diff --git a/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/AbstractRTreeExamplesTest.java b/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/AbstractRTreeExamplesTest.java
index 705a976..6a519d0 100644
--- a/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/AbstractRTreeExamplesTest.java
+++ b/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/AbstractRTreeExamplesTest.java
@@ -727,7 +727,7 @@
         if (LOGGER.isLoggable(Level.INFO)) {
             LOGGER.info("Scan:");
         }
-        ITreeIndexCursor scanCursor = (ITreeIndexCursor) indexAccessor.createSearchCursor();
+        ITreeIndexCursor scanCursor = (ITreeIndexCursor) indexAccessor.createSearchCursor(false);
         SearchPredicate nullPred = new SearchPredicate(null, null);
         indexAccessor.search(scanCursor, nullPred);
         try {
@@ -786,7 +786,7 @@
             String kString = TupleUtils.printTuple(key, fieldSerdes);
             LOGGER.info("Range-Search using key: " + kString);
         }
-        ITreeIndexCursor rangeCursor = (ITreeIndexCursor) indexAccessor.createSearchCursor();
+        ITreeIndexCursor rangeCursor = (ITreeIndexCursor) indexAccessor.createSearchCursor(false);
         MultiComparator cmp = RTreeUtils.getSearchMultiComparator(cmpFactories, key);
         SearchPredicate rangePred = new SearchPredicate(key, cmp);
         indexAccessor.search(rangeCursor, rangePred);
diff --git a/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/RTreeTestUtils.java b/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/RTreeTestUtils.java
index f93a007..af7cf14 100644
--- a/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/RTreeTestUtils.java
+++ b/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/RTreeTestUtils.java
@@ -67,7 +67,7 @@
         AbstractRTreeTestContext ctx = (AbstractRTreeTestContext) ictx;
         MultiComparator cmp = RTreeUtils.getSearchMultiComparator(ctx.getComparatorFactories(), key);
 
-        ITreeIndexCursor searchCursor = (ITreeIndexCursor) ctx.getIndexAccessor().createSearchCursor();
+        ITreeIndexCursor searchCursor = (ITreeIndexCursor) ctx.getIndexAccessor().createSearchCursor(false);
         SearchPredicate searchPred = new SearchPredicate(key, cmp);
         ctx.getIndexAccessor().search(searchCursor, searchPred);
 
diff --git a/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/test/support/TestTaskContext.java b/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/test/support/TestTaskContext.java
index 10b5582..f18099b 100644
--- a/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/test/support/TestTaskContext.java
+++ b/hyracks/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/test/support/TestTaskContext.java
@@ -46,6 +46,10 @@
     public ByteBuffer allocateFrame() {
         return jobletContext.allocateFrame();
     }
+    
+    @Override
+    public void deallocateFrames(int frameCount) {
+    }
 
     @Override
     public int getFrameSize() {
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeSortedInsertTest.java b/hyracks/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeSortedInsertTest.java
new file mode 100644
index 0000000..5e24c52
--- /dev/null
+++ b/hyracks/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeSortedInsertTest.java
@@ -0,0 +1,68 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.hyracks.storage.am.btree;
+
+import java.util.Random;
+
+import org.junit.After;
+import org.junit.Before;
+
+import edu.uci.ics.hyracks.api.dataflow.value.ISerializerDeserializer;
+import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+import edu.uci.ics.hyracks.storage.am.btree.frames.BTreeLeafFrameType;
+import edu.uci.ics.hyracks.storage.am.btree.util.BTreeTestContext;
+import edu.uci.ics.hyracks.storage.am.btree.util.BTreeTestHarness;
+
+/**
+ * Tests the BTree insert operation with sorted stream of strings and integer fields using
+ * various numbers of key and payload fields. Each tests first fills a BTree with
+ * randomly generated tuples. We compare the following operations against expected results:
+ * 1) Point searches for all tuples
+ * 2) Ordered scan
+ * 3) Disk-order scan
+ * 4) Range search (and prefix search for composite keys)
+ */
+public class BTreeSortedInsertTest extends OrderedIndexSortedInsertTest {
+
+    private final BTreeTestHarness harness = new BTreeTestHarness();
+
+    public BTreeSortedInsertTest() {
+        super(BTreeTestHarness.LEAF_FRAMES_TO_TEST);
+    }
+
+    @Before
+    public void setUp() throws HyracksDataException {
+        harness.setUp();
+    }
+
+    @After
+    public void tearDown() throws HyracksDataException {
+        harness.tearDown();
+    }
+
+    @SuppressWarnings("rawtypes")
+    @Override
+    protected OrderedIndexTestContext createTestContext(ISerializerDeserializer[] fieldSerdes, int numKeys,
+            BTreeLeafFrameType leafType) throws Exception {
+        return BTreeTestContext.create(harness.getBufferCache(), harness.getFileMapProvider(),
+                harness.getFileReference(), fieldSerdes, numKeys, leafType);
+    }
+
+    @Override
+    protected Random getRandom() {
+        return harness.getRandom();
+    }
+}
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/StorageManagerTest.java b/hyracks/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/StorageManagerTest.java
index 29da625..5f77d68 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/StorageManagerTest.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/StorageManagerTest.java
@@ -154,7 +154,7 @@
                         if (LOGGER.isLoggable(Level.INFO)) {
                             LOGGER.info(workerId + " X UNLATCHING: " + plPage.pageId);
                         }
-                        plPage.page.releaseWriteLatch();
+                        plPage.page.releaseWriteLatch(true);
                     }
                 }
                 if (LOGGER.isLoggable(Level.INFO)) {
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/multithread/BTreeTestWorker.java b/hyracks/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/multithread/BTreeTestWorker.java
index 22d3e6a..2d7a318 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/multithread/BTreeTestWorker.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/multithread/BTreeTestWorker.java
@@ -51,7 +51,7 @@
     @Override
     public void performOp(ITupleReference tuple, TestOperation op) throws HyracksDataException, IndexException {
         BTree.BTreeAccessor accessor = (BTree.BTreeAccessor) indexAccessor;
-        ITreeIndexCursor searchCursor = accessor.createSearchCursor();
+        ITreeIndexCursor searchCursor = accessor.createSearchCursor(false);
         ITreeIndexCursor diskOrderScanCursor = accessor.createDiskOrderScanCursor();
         MultiComparator cmp = accessor.getOpContext().cmp;
         RangePredicate rangePred = new RangePredicate(tuple, tuple, true, true, cmp, cmp);
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeSearchOperationCallbackTest.java b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeSearchOperationCallbackTest.java
index f1a5355..afaf30b 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeSearchOperationCallbackTest.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeSearchOperationCallbackTest.java
@@ -97,7 +97,7 @@
         public SearchTask() throws HyracksDataException {
             this.cb = new SynchronizingSearchOperationCallback();
             this.accessor = index.createAccessor(NoOpOperationCallback.INSTANCE, cb);
-            this.cursor = accessor.createSearchCursor();
+            this.cursor = accessor.createSearchCursor(false);
             this.predicate = new RangePredicate();
             this.builder = new ArrayTupleBuilder(NUM_KEY_FIELDS);
             this.tuple = new ArrayTupleReference();
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeTestWorker.java b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeTestWorker.java
index 35ecc20..8ab5d22 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeTestWorker.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeTestWorker.java
@@ -52,7 +52,7 @@
     @Override
     public void performOp(ITupleReference tuple, TestOperation op) throws HyracksDataException, IndexException {
         LSMBTreeAccessor accessor = (LSMBTreeAccessor) indexAccessor;
-        IIndexCursor searchCursor = accessor.createSearchCursor();
+        IIndexCursor searchCursor = accessor.createSearchCursor(false);
         MultiComparator cmp = accessor.getMultiComparator();
         RangePredicate rangePred = new RangePredicate(tuple, tuple, true, true, cmp, cmp);
 
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/LSMTreeRunner.java b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/LSMTreeRunner.java
index 3591f78..fb06a7e 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/LSMTreeRunner.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/LSMTreeRunner.java
@@ -20,10 +20,12 @@
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.List;
+import java.util.concurrent.ThreadFactory;
 
 import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.ITypeTraits;
+import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.api.exceptions.HyracksException;
 import edu.uci.ics.hyracks.api.io.FileReference;
 import edu.uci.ics.hyracks.control.nc.io.IOManager;
@@ -37,9 +39,9 @@
 import edu.uci.ics.hyracks.storage.am.lsm.btree.util.LSMBTreeUtils;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperationScheduler;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.IVirtualBufferCache;
+import edu.uci.ics.hyracks.storage.am.lsm.common.impls.AsynchronousScheduler;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.NoMergePolicy;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.NoOpIOOperationCallback;
-import edu.uci.ics.hyracks.storage.am.lsm.common.impls.SynchronousScheduler;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.ThreadCountingTracker;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.VirtualBufferCache;
 import edu.uci.ics.hyracks.storage.common.buffercache.HeapBufferAllocator;
@@ -50,8 +52,8 @@
 
 public class LSMTreeRunner implements IExperimentRunner {
 
-    private static final int MAX_OPEN_FILES = 10000;
-    private static final int HYRACKS_FRAME_SIZE = 128;
+    private static final int MAX_OPEN_FILES = Integer.MAX_VALUE;
+    private static final int HYRACKS_FRAME_SIZE = 131072;
 
     protected IHyracksTaskContext ctx;
     protected IOManager ioManager;
@@ -61,7 +63,7 @@
 
     protected final static SimpleDateFormat simpleDateFormat = new SimpleDateFormat("ddMMyy-hhmmssSS");
     protected final static String sep = System.getProperty("file.separator");
-    protected final static String classDir = "/lsmtree/";
+    protected final static String classDir = "/tmp/lsmtree/";
     protected String onDiskDir;
     protected FileReference file;
 
@@ -71,6 +73,11 @@
     protected IBufferCache memBufferCache;
     private final int onDiskPageSize;
     private final int onDiskNumPages;
+    private final static ThreadFactory threadFactory = new ThreadFactory() {
+        public Thread newThread(Runnable r) {
+            return new Thread(r);
+        }
+    };
 
     public LSMTreeRunner(int numBatches, int inMemPageSize, int inMemNumPages, int onDiskPageSize, int onDiskNumPages,
             ITypeTraits[] typeTraits, IBinaryComparatorFactory[] cmpFactories, int[] bloomFilterKeyFields,
@@ -93,11 +100,13 @@
         List<IVirtualBufferCache> virtualBufferCaches = new ArrayList<IVirtualBufferCache>();
         for (int i = 0; i < 2; i++) {
             IVirtualBufferCache virtualBufferCache = new VirtualBufferCache(new HeapBufferAllocator(), inMemPageSize,
-                    inMemNumPages);
+                    inMemNumPages / 2);
             virtualBufferCaches.add(virtualBufferCache);
         }
 
-        this.ioScheduler = SynchronousScheduler.INSTANCE;
+        this.ioScheduler = AsynchronousScheduler.INSTANCE;
+        AsynchronousScheduler.INSTANCE.init(threadFactory);
+
         lsmtree = LSMBTreeUtils.createLSMTree(virtualBufferCaches, file, bufferCache, fmp, typeTraits, cmpFactories,
                 bloomFilterKeyFields, bloomFilterFalsePositiveRate, NoMergePolicy.INSTANCE,
                 new ThreadCountingTracker(), ioScheduler, NoOpIOOperationCallback.INSTANCE);
@@ -133,15 +142,23 @@
 
     @Override
     public void reset() throws Exception {
+        try {
+            lsmtree.deactivate();
+        } catch (HyracksDataException e) {
+            // ignore
+        }
+        try {
+            lsmtree.destroy();
+        } catch (HyracksDataException e) {
+            // ignore
+        }
+
         lsmtree.create();
+        lsmtree.activate();
     }
 
     @Override
     public void deinit() throws Exception {
-        bufferCache.closeFile(lsmtreeFileId);
-        bufferCache.close();
-        memBufferCache.closeFile(lsmtreeFileId);
-        memBufferCache.close();
     }
 
     public class LSMTreeThread extends Thread {
@@ -166,6 +183,7 @@
                         } catch (TreeIndexException e) {
                         }
                     }
+                    dataGen.releaseBatch(batch);
                 }
             } catch (Exception e) {
                 e.printStackTrace();
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/PerfExperiment.java b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/PerfExperiment.java
index 641362e..2354550 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/PerfExperiment.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/PerfExperiment.java
@@ -31,18 +31,20 @@
     public static void main(String[] args) throws Exception {
         // Disable logging so we can better see the output times.
         Enumeration<String> loggers = LogManager.getLogManager().getLoggerNames();
-        while(loggers.hasMoreElements()) {
+        while (loggers.hasMoreElements()) {
             String loggerName = loggers.nextElement();
             Logger logger = LogManager.getLogManager().getLogger(loggerName);
             logger.setLevel(Level.OFF);
         }
-        
-        int numTuples = 100000; // 100K
+        boolean sorted = Boolean.parseBoolean(args[0]);
+        int numThreads =  Integer.parseInt(args[1]);
+
+        //int numTuples = 100000; // 100K
         //int numTuples = 1000000; // 1M
         //int numTuples = 2000000; // 2M
         //int numTuples = 3000000; // 3M
         //int numTuples = 10000000; // 10M
-        //int numTuples = 20000000; // 20M
+        int numTuples = 20000000; // 20M
         //int numTuples = 30000000; // 30M
         //int numTuples = 40000000; // 40M
         //int numTuples = 60000000; // 60M
@@ -50,27 +52,41 @@
         //int numTuples = 200000000; // 200M
         int batchSize = 10000;
         int numBatches = numTuples / batchSize;
-        
+
+        int payLoadSize = 240;
         ISerializerDeserializer[] fieldSerdes = new ISerializerDeserializer[] { IntegerSerializerDeserializer.INSTANCE };
-        ITypeTraits[] typeTraits = SerdeUtils.serdesToTypeTraits(fieldSerdes, 30);
-        
-        IBinaryComparatorFactory[] cmpFactories = SerdeUtils.serdesToComparatorFactories(fieldSerdes, fieldSerdes.length);
-        
+        ITypeTraits[] typeTraits = SerdeUtils.serdesToTypeTraits(fieldSerdes, payLoadSize);
+
+        IBinaryComparatorFactory[] cmpFactories = SerdeUtils.serdesToComparatorFactories(fieldSerdes,
+                fieldSerdes.length);
+        int[] bloomFilterKeyFields = new int[cmpFactories.length];
+        for (int i = 0; i < bloomFilterKeyFields.length; i++) {
+            bloomFilterKeyFields[i] = i;
+        }
+        double bloomFilterFalsePositiveRate = 0.01;
+
         //int repeats = 1000;
         int repeats = 1;
         long[] times = new long[repeats];
 
-        int numThreads = 2;
+//        int numThreads = 4;
+//        boolean sorted = true;
         for (int i = 0; i < repeats; i++) {
             //ConcurrentSkipListRunner runner = new ConcurrentSkipListRunner(numBatches, batchSize, tupleSize, typeTraits, cmp);
-            InMemoryBTreeRunner runner = new InMemoryBTreeRunner(numBatches, 8192, 100000, typeTraits, cmpFactories);
+            //InMemoryBTreeRunner runner = new InMemoryBTreeRunner(numBatches, 8192, 100000, typeTraits, cmpFactories);
             //BTreeBulkLoadRunner runner = new BTreeBulkLoadRunner(numBatches, 8192, 100000, typeTraits, cmp, 1.0f);
-        	//BTreeRunner runner = new BTreeRunner(numBatches, 8192, 100000, typeTraits, cmp);
-        	//String btreeName = "071211";
-        	//BTreeSearchRunner runner = new BTreeSearchRunner(btreeName, 10, numBatches, 8192, 25000, typeTraits, cmp);
-        	//LSMTreeRunner runner = new LSMTreeRunner(numBatches, 8192, 100, 8192, 250, typeTraits, cmp);
-        	//LSMTreeSearchRunner runner = new LSMTreeSearchRunner(100000, numBatches, 8192, 24750, 8192, 250, typeTraits, cmp); 
-            DataGenThread dataGen = new DataGenThread(numThreads, numBatches, batchSize, fieldSerdes, 30, 50, 10, false);
+            //BTreeRunner runner = new BTreeRunner(numBatches, 8192, 100000, typeTraits, cmp);
+            //String btreeName = "071211";
+            //BTreeSearchRunner runner = new BTreeSearchRunner(btreeName, 10, numBatches, 8192, 25000, typeTraits, cmp);
+            //LSMTreeRunner runner = new LSMTreeRunner(numBatches, 8192, 100, 8192, 250, typeTraits, cmp);
+            //LSMTreeSearchRunner runner = new LSMTreeSearchRunner(100000, numBatches, 8192, 24750, 8192, 250, typeTraits, cmp); 
+            int inMemPageSize = 131072; // 128kb
+            int onDiskPageSize = inMemPageSize;
+            int inMemNumPages = 8192; // 1GB
+            int onDiskNumPages = 16384; // 2GB
+            LSMTreeRunner runner = new LSMTreeRunner(numBatches, inMemPageSize, inMemNumPages, onDiskPageSize,
+                    onDiskNumPages, typeTraits, cmpFactories, bloomFilterKeyFields, bloomFilterFalsePositiveRate);
+            DataGenThread dataGen = new DataGenThread(numThreads, numBatches, batchSize, fieldSerdes, payLoadSize, 50, 10, sorted);
             dataGen.start();
             runner.reset();
             times[i] = runner.runExperiment(dataGen, numThreads);
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/multithread/LSMInvertedIndexTestWorker.java b/hyracks/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/multithread/LSMInvertedIndexTestWorker.java
index 35afd09..34b3ff7 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/multithread/LSMInvertedIndexTestWorker.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/multithread/LSMInvertedIndexTestWorker.java
@@ -58,7 +58,7 @@
     @Override
     public void performOp(ITupleReference tuple, TestOperation op) throws HyracksDataException, IndexException {
         LSMInvertedIndexAccessor accessor = (LSMInvertedIndexAccessor) indexAccessor;
-        IIndexCursor searchCursor = accessor.createSearchCursor();
+        IIndexCursor searchCursor = accessor.createSearchCursor(false);
         IIndexCursor rangeSearchCursor = accessor.createRangeSearchCursor();
         RangePredicate rangePred = new RangePredicate(null, null, true, true, null, null);
         IBinaryTokenizerFactory tokenizerFactory = invIndex.getTokenizerFactory();
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/util/LSMInvertedIndexTestUtils.java b/hyracks/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/util/LSMInvertedIndexTestUtils.java
index c4e1ac5..58e0ace 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/util/LSMInvertedIndexTestUtils.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/util/LSMInvertedIndexTestUtils.java
@@ -510,7 +510,7 @@
             searchPred.setQueryTuple(searchDocument);
             searchPred.setQueryFieldIndex(0);
 
-            IIndexCursor resultCursor = accessor.createSearchCursor();
+            IIndexCursor resultCursor = accessor.createSearchCursor(false);
             boolean panic = false;
             try {
                 accessor.search(resultCursor, searchPred);
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeTestWorker.java b/hyracks/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeTestWorker.java
index c7a86d9..b52b518 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeTestWorker.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeTestWorker.java
@@ -50,7 +50,7 @@
     @Override
     public void performOp(ITupleReference tuple, TestOperation op) throws HyracksDataException, IndexException {
         LSMRTreeAccessor accessor = (LSMRTreeAccessor) indexAccessor;
-        ITreeIndexCursor searchCursor = accessor.createSearchCursor();
+        ITreeIndexCursor searchCursor = accessor.createSearchCursor(false);
         MultiComparator cmp = accessor.getMultiComparator();
         SearchPredicate rangePred = new SearchPredicate(tuple, cmp);
 
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeWithAntiMatterTuplesTestWorker.java b/hyracks/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeWithAntiMatterTuplesTestWorker.java
index 383cbc4..eef80d6 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeWithAntiMatterTuplesTestWorker.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeWithAntiMatterTuplesTestWorker.java
@@ -39,7 +39,7 @@
     @Override
     public void performOp(ITupleReference tuple, TestOperation op) throws HyracksDataException, IndexException {
         LSMRTreeWithAntiMatterTuplesAccessor accessor = (LSMRTreeWithAntiMatterTuplesAccessor) indexAccessor;
-        ITreeIndexCursor searchCursor = accessor.createSearchCursor();
+        ITreeIndexCursor searchCursor = accessor.createSearchCursor(false);
         MultiComparator cmp = accessor.getMultiComparator();
         SearchPredicate rangePred = new SearchPredicate(tuple, cmp);
 
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/rtree/multithread/RTreeTestWorker.java b/hyracks/hyracks-tests/hyracks-storage-am-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/rtree/multithread/RTreeTestWorker.java
index bc5d331..04cf044 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/rtree/multithread/RTreeTestWorker.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/rtree/multithread/RTreeTestWorker.java
@@ -49,7 +49,7 @@
     @Override
     public void performOp(ITupleReference tuple, TestOperation op) throws HyracksDataException, IndexException {
         RTree.RTreeAccessor accessor = (RTree.RTreeAccessor) indexAccessor;
-        IIndexCursor searchCursor = accessor.createSearchCursor();
+        IIndexCursor searchCursor = accessor.createSearchCursor(false);
         ITreeIndexCursor diskOrderScanCursor = accessor.createDiskOrderScanCursor();
         MultiComparator cmp = accessor.getOpContext().cmp;
         SearchPredicate rangePred = new SearchPredicate(tuple, cmp);
diff --git a/hyracks/hyracks-tests/hyracks-storage-common-test/src/test/java/edu/uci/ics/hyracks/storage/common/BufferCacheRegressionTest.java b/hyracks/hyracks-tests/hyracks-storage-common-test/src/test/java/edu/uci/ics/hyracks/storage/common/BufferCacheRegressionTest.java
index 577abbb..ba1715f 100644
--- a/hyracks/hyracks-tests/hyracks-storage-common-test/src/test/java/edu/uci/ics/hyracks/storage/common/BufferCacheRegressionTest.java
+++ b/hyracks/hyracks-tests/hyracks-storage-common-test/src/test/java/edu/uci/ics/hyracks/storage/common/BufferCacheRegressionTest.java
@@ -81,7 +81,7 @@
                 buf.put(Byte.MAX_VALUE);
             }
         } finally {
-            writePage.releaseWriteLatch();
+            writePage.releaseWriteLatch(true);
             bufferCache.unpin(writePage);
         }
         bufferCache.closeFile(firstFileId);
diff --git a/hyracks/hyracks-tests/hyracks-storage-common-test/src/test/java/edu/uci/ics/hyracks/storage/common/BufferCacheTest.java b/hyracks/hyracks-tests/hyracks-storage-common-test/src/test/java/edu/uci/ics/hyracks/storage/common/BufferCacheTest.java
index c67386e..118a27c 100644
--- a/hyracks/hyracks-tests/hyracks-storage-common-test/src/test/java/edu/uci/ics/hyracks/storage/common/BufferCacheTest.java
+++ b/hyracks/hyracks-tests/hyracks-storage-common-test/src/test/java/edu/uci/ics/hyracks/storage/common/BufferCacheTest.java
@@ -91,7 +91,7 @@
             bufferCache.unpin(page2);
 
         } finally {
-            page.releaseWriteLatch();
+            page.releaseWriteLatch(true);
             bufferCache.unpin(page);
         }
 
@@ -228,7 +228,7 @@
                 }
                 pageContents.put(fileId, values);
             } finally {
-                page.releaseWriteLatch();
+                page.releaseWriteLatch(true);
                 bufferCache.unpin(page);
             }
         }
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/graph/Vertex.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/graph/Vertex.java
index 26cb8d0..a42b411 100644
--- a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/graph/Vertex.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/graph/Vertex.java
@@ -258,8 +258,9 @@
     @Override
     final public void readFields(DataInput in) throws IOException {
         reset();
-        if (vertexId == null)
+        if (vertexId == null) {
             vertexId = BspUtils.<I> createVertexIndex(getContext().getConfiguration());
+        }
         vertexId.readFields(in);
         delegate.setVertexId(vertexId);
         boolean hasVertexValue = in.readBoolean();
@@ -576,15 +577,6 @@
         return context;
     }
 
-    /**
-     * Pregelix internal use only
-     * 
-     * @param context
-     */
-    public static final void setContext(TaskAttemptContext context) {
-        Vertex.context = context;
-    }
-
     @Override
     public int hashCode() {
         return vertexId.hashCode();
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/job/PregelixJob.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/job/PregelixJob.java
index 6549c52..15aa7c4 100644
--- a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/job/PregelixJob.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/job/PregelixJob.java
@@ -182,6 +182,15 @@
     }
 
     /**
+     * Set whether the vertex state length is fixed
+     * 
+     * @param jobId
+     */
+    final public void setFixedVertexValueSize(boolean fixedSize) {
+        getConfiguration().setBoolean(INCREASE_STATE_LENGTH, !fixedSize);
+    }
+
+    /**
      * Set the frame size for a job
      * 
      * @param frameSize
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/BspUtils.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/BspUtils.java
index 4ee1deb..e79d4d2 100644
--- a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/BspUtils.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/BspUtils.java
@@ -37,11 +37,6 @@
  * them.
  */
 public class BspUtils {
-    private static Configuration defaultConf = null;
-
-    public static void setDefaultConfiguration(Configuration conf) {
-        defaultConf = conf;
-    }
 
     /**
      * Get the user's subclassed {@link VertexInputFormat}.
@@ -209,8 +204,6 @@
      */
     @SuppressWarnings("unchecked")
     public static <I extends Writable> Class<I> getVertexIndexClass(Configuration conf) {
-        if (conf == null)
-            conf = defaultConf;
         return (Class<I>) conf.getClass(PregelixJob.VERTEX_INDEX_CLASS, WritableComparable.class);
     }
 
@@ -302,8 +295,6 @@
      */
     @SuppressWarnings("unchecked")
     public static <M extends WritableSizable> Class<M> getMessageValueClass(Configuration conf) {
-        if (conf == null)
-            conf = defaultConf;
         return (Class<M>) conf.getClass(PregelixJob.MESSAGE_VALUE_CLASS, Writable.class);
     }
 
@@ -316,8 +307,6 @@
      */
     @SuppressWarnings("unchecked")
     public static <M extends Writable> Class<M> getPartialAggregateValueClass(Configuration conf) {
-        if (conf == null)
-            conf = defaultConf;
         return (Class<M>) conf.getClass(PregelixJob.PARTIAL_AGGREGATE_VALUE_CLASS, Writable.class);
     }
 
@@ -330,8 +319,6 @@
      */
     @SuppressWarnings("unchecked")
     public static <M extends Writable> Class<M> getPartialCombineValueClass(Configuration conf) {
-        if (conf == null)
-            conf = defaultConf;
         return (Class<M>) conf.getClass(PregelixJob.PARTIAL_COMBINE_VALUE_CLASS, Writable.class);
     }
 
@@ -344,8 +331,6 @@
      */
     @SuppressWarnings("unchecked")
     public static Class<? extends NormalizedKeyComputer> getNormalizedKeyComputerClass(Configuration conf) {
-        if (conf == null)
-            conf = defaultConf;
         return (Class<? extends NormalizedKeyComputer>) conf.getClass(PregelixJob.NMK_COMPUTER_CLASS,
                 NormalizedKeyComputer.class);
     }
@@ -359,8 +344,6 @@
      */
     @SuppressWarnings("unchecked")
     public static <M extends Writable> Class<M> getFinalAggregateValueClass(Configuration conf) {
-        if (conf == null)
-            conf = defaultConf;
         return (Class<M>) conf.getClass(PregelixJob.FINAL_AGGREGATE_VALUE_CLASS, Writable.class);
     }
 
@@ -488,8 +471,6 @@
      */
     @SuppressWarnings({ "unchecked", "rawtypes" })
     public static <V extends VertexPartitioner> Class<V> getVertexPartitionerClass(Configuration conf) {
-        if (conf == null)
-            conf = defaultConf;
         return (Class<V>) conf.getClass(PregelixJob.PARTITIONER_CLASS, null, VertexPartitioner.class);
     }
 
@@ -502,8 +483,6 @@
      */
     @SuppressWarnings("unchecked")
     public static <V extends ICheckpointHook> Class<V> getCheckpointHookClass(Configuration conf) {
-        if (conf == null)
-            conf = defaultConf;
         return (Class<V>) conf.getClass(PregelixJob.CKP_CLASS, DefaultCheckpointHook.class, ICheckpointHook.class);
     }
 
@@ -515,7 +494,7 @@
      * @return the boolean setting of the parameter, by default it is false
      */
     public static boolean getDynamicVertexValueSize(Configuration conf) {
-        return conf.getBoolean(PregelixJob.INCREASE_STATE_LENGTH, false);
+        return conf.getBoolean(PregelixJob.INCREASE_STATE_LENGTH, true);
     }
 
     /**
diff --git a/pregelix/pregelix-benchmark/pom.xml b/pregelix/pregelix-benchmark/pom.xml
index 4d7d456..c1344ea 100644
--- a/pregelix/pregelix-benchmark/pom.xml
+++ b/pregelix/pregelix-benchmark/pom.xml
@@ -12,6 +12,42 @@
 	<artifactId>pregelix-benchmark</artifactId>
 	<name>pregelix-benchmark</name>
 	<url>http://maven.apache.org</url>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<version>2.0.2</version>
+				<configuration>
+					<source>1.7</source>
+					<target>1.7</target>
+					<fork>true</fork>
+				</configuration>
+			</plugin>
+
+			<plugin>
+				<artifactId>maven-assembly-plugin</artifactId>
+				<version>2.2-beta-5</version>
+				<configuration>
+					<descriptorRefs>
+						<descriptorRef>jar-with-dependencies</descriptorRef>
+					</descriptorRefs>
+				</configuration>
+				<executions>
+					<execution>
+						<id>make-my-jar-with-dependencies</id>
+						<phase>package</phase>
+						<goals>
+							<goal>single</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+
+
 	<dependencies>
 		<dependency>
 			<groupId>junit</groupId>
@@ -26,6 +62,12 @@
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
+			<groupId>org.apache.giraph</groupId>
+			<artifactId>giraph-examples</artifactId>
+			<version>1.0.0</version>
+			<scope>compile</scope>
+		</dependency>
+		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-hdfs-core</artifactId>
 			<version>0.2.10-SNAPSHOT</version>
diff --git a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/PageRankVertex.java b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/PageRankVertex.java
deleted file mode 100644
index 04c29de..0000000
--- a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/PageRankVertex.java
+++ /dev/null
@@ -1,58 +0,0 @@
-/*
- * Copyright 2009-2013 by The Regents of the University of California
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * you may obtain a copy of the License from
- * 
- *     http://www.apache.org/licenses/LICENSE-2.0
- * 
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package edu.uci.ics.pregelix.benchmark;
-
-import org.apache.giraph.graph.Vertex;
-import org.apache.hadoop.io.DoubleWritable;
-import org.apache.hadoop.io.FloatWritable;
-import org.apache.hadoop.io.VLongWritable;
-
-/**
- * Demonstrates the basic Pregel PageRank implementation.
- */
-public class PageRankVertex extends Vertex<VLongWritable, DoubleWritable, FloatWritable, DoubleWritable> {
-
-    public static final String ITERATIONS = "HyracksPageRankVertex.iteration";
-    private final DoubleWritable vertexValue = new DoubleWritable();
-    private final DoubleWritable msg = new DoubleWritable();
-    private int maxIteration = -1;
-
-    @Override
-    public void compute(Iterable<DoubleWritable> msgIterator) {
-        if (maxIteration < 0) {
-            maxIteration = getContext().getConfiguration().getInt(ITERATIONS, 10);
-        }
-        if (getSuperstep() == 1) {
-            vertexValue.set(1.0 / getTotalNumVertices());
-        }
-        if (getSuperstep() >= 2 && getSuperstep() <= maxIteration) {
-            double sum = 0;
-            for (DoubleWritable msg : msgIterator) {
-                sum += msg.get();
-            }
-            vertexValue.set((0.15 / getTotalNumVertices()) + 0.85 * sum);
-        }
-
-        if (getSuperstep() >= 1 && getSuperstep() < maxIteration) {
-            long edges = getNumEdges();
-            msg.set(vertexValue.get() / edges);
-            sendMessageToAllEdges(msg);
-        } else {
-            voteToHalt();
-        }
-    }
-
-}
diff --git a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/TextPageRankInputFormat.java b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io/TextCCInputFormat.java
similarity index 60%
copy from pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/TextPageRankInputFormat.java
copy to pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io/TextCCInputFormat.java
index 3d85f66..b290907 100644
--- a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/TextPageRankInputFormat.java
+++ b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io/TextCCInputFormat.java
@@ -12,7 +12,8 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package edu.uci.ics.pregelix.benchmark;
+
+package edu.uci.ics.pregelix.benchmark.io;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -24,14 +25,13 @@
 import org.apache.giraph.edge.Edge;
 import org.apache.giraph.edge.MapMutableEdge;
 import org.apache.giraph.io.formats.TextVertexInputFormat;
-import org.apache.hadoop.io.DoubleWritable;
-import org.apache.hadoop.io.FloatWritable;
+import org.apache.hadoop.io.LongWritable;
+import org.apache.hadoop.io.NullWritable;
 import org.apache.hadoop.io.Text;
-import org.apache.hadoop.io.VLongWritable;
 import org.apache.hadoop.mapreduce.InputSplit;
 import org.apache.hadoop.mapreduce.TaskAttemptContext;
 
-public class TextPageRankInputFormat extends TextVertexInputFormat<VLongWritable, DoubleWritable, FloatWritable> {
+public class TextCCInputFormat extends TextVertexInputFormat<LongWritable, LongWritable, NullWritable> {
 
     @Override
     public TextVertexReader createVertexReader(InputSplit split, TaskAttemptContext context) throws IOException {
@@ -39,25 +39,25 @@
             String[] items;
 
             @Override
-            protected VLongWritable getId(Text line) throws IOException {
+            protected LongWritable getId(Text line) throws IOException {
                 items = line.toString().split(" ");
-                return new VLongWritable(Long.parseLong(items[0]));
+                return new LongWritable(Long.parseLong(items[0]));
             }
 
             @Override
-            protected DoubleWritable getValue(Text line) throws IOException {
+            protected LongWritable getValue(Text line) throws IOException {
                 return null;
             }
 
             @Override
-            protected Iterable<Edge<VLongWritable, FloatWritable>> getEdges(Text line) throws IOException {
-                List<Edge<VLongWritable, FloatWritable>> edges = new ArrayList<Edge<VLongWritable, FloatWritable>>();
-                Map<VLongWritable, FloatWritable> edgeMap = new HashMap<VLongWritable, FloatWritable>();
+            protected Iterable<Edge<LongWritable, NullWritable>> getEdges(Text line) throws IOException {
+                List<Edge<LongWritable, NullWritable>> edges = new ArrayList<Edge<LongWritable, NullWritable>>();
+                Map<LongWritable, NullWritable> edgeMap = new HashMap<LongWritable, NullWritable>();
                 for (int i = 1; i < items.length; i++) {
-                    edgeMap.put(new VLongWritable(Long.parseLong(items[i])), null);
+                    edgeMap.put(new LongWritable(Long.parseLong(items[i])), null);
                 }
-                for (Entry<VLongWritable, FloatWritable> entry : edgeMap.entrySet()) {
-                    MapMutableEdge<VLongWritable, FloatWritable> edge = new MapMutableEdge<VLongWritable, FloatWritable>();
+                for (Entry<LongWritable, NullWritable> entry : edgeMap.entrySet()) {
+                    MapMutableEdge<LongWritable, NullWritable> edge = new MapMutableEdge<LongWritable, NullWritable>();
                     edge.setEntry(entry);
                     edge.setValue(null);
                     edges.add(edge);
@@ -67,4 +67,5 @@
 
         };
     }
+
 }
diff --git a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io/TextCCOutputFormat.java b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io/TextCCOutputFormat.java
new file mode 100644
index 0000000..770c6e1
--- /dev/null
+++ b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io/TextCCOutputFormat.java
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.pregelix.benchmark.io;
+
+import java.io.IOException;
+
+import org.apache.giraph.graph.Vertex;
+import org.apache.giraph.io.formats.TextVertexOutputFormat;
+import org.apache.hadoop.io.LongWritable;
+import org.apache.hadoop.io.NullWritable;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.mapreduce.TaskAttemptContext;
+
+public class TextCCOutputFormat extends TextVertexOutputFormat<LongWritable, LongWritable, NullWritable> {
+
+    @Override
+    public TextVertexWriter createVertexWriter(TaskAttemptContext context) throws IOException, InterruptedException {
+        return new TextVertexWriterToEachLine() {
+
+            @Override
+            protected Text convertVertexToLine(Vertex<LongWritable, LongWritable, NullWritable, ?> vertex)
+                    throws IOException {
+                return new Text(vertex.getId() + " " + vertex.getValue());
+            }
+
+        };
+    }
+
+}
diff --git a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/TextPageRankInputFormat.java b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io/TextPRInputFormat.java
similarity index 64%
copy from pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/TextPageRankInputFormat.java
copy to pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io/TextPRInputFormat.java
index 3d85f66..38eef3a 100644
--- a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/TextPageRankInputFormat.java
+++ b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io/TextPRInputFormat.java
@@ -12,7 +12,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package edu.uci.ics.pregelix.benchmark;
+package edu.uci.ics.pregelix.benchmark.io;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -25,13 +25,13 @@
 import org.apache.giraph.edge.MapMutableEdge;
 import org.apache.giraph.io.formats.TextVertexInputFormat;
 import org.apache.hadoop.io.DoubleWritable;
-import org.apache.hadoop.io.FloatWritable;
+import org.apache.hadoop.io.LongWritable;
+import org.apache.hadoop.io.NullWritable;
 import org.apache.hadoop.io.Text;
-import org.apache.hadoop.io.VLongWritable;
 import org.apache.hadoop.mapreduce.InputSplit;
 import org.apache.hadoop.mapreduce.TaskAttemptContext;
 
-public class TextPageRankInputFormat extends TextVertexInputFormat<VLongWritable, DoubleWritable, FloatWritable> {
+public class TextPRInputFormat extends TextVertexInputFormat<LongWritable, DoubleWritable, NullWritable> {
 
     @Override
     public TextVertexReader createVertexReader(InputSplit split, TaskAttemptContext context) throws IOException {
@@ -39,9 +39,9 @@
             String[] items;
 
             @Override
-            protected VLongWritable getId(Text line) throws IOException {
+            protected LongWritable getId(Text line) throws IOException {
                 items = line.toString().split(" ");
-                return new VLongWritable(Long.parseLong(items[0]));
+                return new LongWritable(Long.parseLong(items[0]));
             }
 
             @Override
@@ -50,14 +50,14 @@
             }
 
             @Override
-            protected Iterable<Edge<VLongWritable, FloatWritable>> getEdges(Text line) throws IOException {
-                List<Edge<VLongWritable, FloatWritable>> edges = new ArrayList<Edge<VLongWritable, FloatWritable>>();
-                Map<VLongWritable, FloatWritable> edgeMap = new HashMap<VLongWritable, FloatWritable>();
+            protected Iterable<Edge<LongWritable, NullWritable>> getEdges(Text line) throws IOException {
+                List<Edge<LongWritable, NullWritable>> edges = new ArrayList<Edge<LongWritable, NullWritable>>();
+                Map<LongWritable, NullWritable> edgeMap = new HashMap<LongWritable, NullWritable>();
                 for (int i = 1; i < items.length; i++) {
-                    edgeMap.put(new VLongWritable(Long.parseLong(items[i])), null);
+                    edgeMap.put(new LongWritable(Long.parseLong(items[i])), null);
                 }
-                for (Entry<VLongWritable, FloatWritable> entry : edgeMap.entrySet()) {
-                    MapMutableEdge<VLongWritable, FloatWritable> edge = new MapMutableEdge<VLongWritable, FloatWritable>();
+                for (Entry<LongWritable, NullWritable> entry : edgeMap.entrySet()) {
+                    MapMutableEdge<LongWritable, NullWritable> edge = new MapMutableEdge<LongWritable, NullWritable>();
                     edge.setEntry(entry);
                     edge.setValue(null);
                     edges.add(edge);
diff --git a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io/TextPROutputFormat.java b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io/TextPROutputFormat.java
new file mode 100644
index 0000000..b14de6f
--- /dev/null
+++ b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io/TextPROutputFormat.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.pregelix.benchmark.io;
+
+import java.io.IOException;
+
+import org.apache.giraph.graph.Vertex;
+import org.apache.giraph.io.formats.TextVertexOutputFormat;
+import org.apache.hadoop.io.DoubleWritable;
+import org.apache.hadoop.io.LongWritable;
+import org.apache.hadoop.io.NullWritable;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.mapreduce.TaskAttemptContext;
+
+public class TextPROutputFormat extends TextVertexOutputFormat<LongWritable, DoubleWritable, NullWritable> {
+
+    @Override
+    public TextVertexWriter createVertexWriter(TaskAttemptContext context) throws IOException, InterruptedException {
+        return new TextVertexWriterToEachLine() {
+
+            @Override
+            protected Text convertVertexToLine(Vertex<LongWritable, DoubleWritable, NullWritable, ?> vertex)
+                    throws IOException {
+                return new Text(vertex.getId() + " " + vertex.getValue());
+            }
+
+        };
+    }
+
+}
diff --git a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/TextPageRankInputFormat.java b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io/TextSPInputFormat.java
similarity index 65%
rename from pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/TextPageRankInputFormat.java
rename to pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io/TextSPInputFormat.java
index 3d85f66..953e93c 100644
--- a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/TextPageRankInputFormat.java
+++ b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io/TextSPInputFormat.java
@@ -12,7 +12,8 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package edu.uci.ics.pregelix.benchmark;
+
+package edu.uci.ics.pregelix.benchmark.io;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -25,13 +26,12 @@
 import org.apache.giraph.edge.MapMutableEdge;
 import org.apache.giraph.io.formats.TextVertexInputFormat;
 import org.apache.hadoop.io.DoubleWritable;
-import org.apache.hadoop.io.FloatWritable;
+import org.apache.hadoop.io.LongWritable;
 import org.apache.hadoop.io.Text;
-import org.apache.hadoop.io.VLongWritable;
 import org.apache.hadoop.mapreduce.InputSplit;
 import org.apache.hadoop.mapreduce.TaskAttemptContext;
 
-public class TextPageRankInputFormat extends TextVertexInputFormat<VLongWritable, DoubleWritable, FloatWritable> {
+public class TextSPInputFormat extends TextVertexInputFormat<LongWritable, DoubleWritable, DoubleWritable> {
 
     @Override
     public TextVertexReader createVertexReader(InputSplit split, TaskAttemptContext context) throws IOException {
@@ -39,9 +39,9 @@
             String[] items;
 
             @Override
-            protected VLongWritable getId(Text line) throws IOException {
+            protected LongWritable getId(Text line) throws IOException {
                 items = line.toString().split(" ");
-                return new VLongWritable(Long.parseLong(items[0]));
+                return new LongWritable(Long.parseLong(items[0]));
             }
 
             @Override
@@ -50,16 +50,16 @@
             }
 
             @Override
-            protected Iterable<Edge<VLongWritable, FloatWritable>> getEdges(Text line) throws IOException {
-                List<Edge<VLongWritable, FloatWritable>> edges = new ArrayList<Edge<VLongWritable, FloatWritable>>();
-                Map<VLongWritable, FloatWritable> edgeMap = new HashMap<VLongWritable, FloatWritable>();
+            protected Iterable<Edge<LongWritable, DoubleWritable>> getEdges(Text line) throws IOException {
+                List<Edge<LongWritable, DoubleWritable>> edges = new ArrayList<Edge<LongWritable, DoubleWritable>>();
+                Map<LongWritable, DoubleWritable> edgeMap = new HashMap<LongWritable, DoubleWritable>();
                 for (int i = 1; i < items.length; i++) {
-                    edgeMap.put(new VLongWritable(Long.parseLong(items[i])), null);
+                    edgeMap.put(new LongWritable(Long.parseLong(items[i])), null);
                 }
-                for (Entry<VLongWritable, FloatWritable> entry : edgeMap.entrySet()) {
-                    MapMutableEdge<VLongWritable, FloatWritable> edge = new MapMutableEdge<VLongWritable, FloatWritable>();
+                for (Entry<LongWritable, DoubleWritable> entry : edgeMap.entrySet()) {
+                    MapMutableEdge<LongWritable, DoubleWritable> edge = new MapMutableEdge<LongWritable, DoubleWritable>();
                     edge.setEntry(entry);
-                    edge.setValue(null);
+                    edge.setValue(new DoubleWritable(1.0));
                     edges.add(edge);
                 }
                 return edges;
@@ -67,4 +67,5 @@
 
         };
     }
+
 }
diff --git a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io2/TextCCInputFormat2.java b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io2/TextCCInputFormat2.java
new file mode 100644
index 0000000..0a70b3c
--- /dev/null
+++ b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io2/TextCCInputFormat2.java
@@ -0,0 +1,72 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.pregelix.benchmark.io2;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import org.apache.giraph.edge.Edge;
+import org.apache.giraph.edge.MapMutableEdge;
+import org.apache.giraph.io.formats.TextVertexInputFormat;
+import org.apache.hadoop.io.LongWritable;
+import org.apache.hadoop.io.NullWritable;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.mapreduce.InputSplit;
+import org.apache.hadoop.mapreduce.TaskAttemptContext;
+
+public class TextCCInputFormat2 extends TextVertexInputFormat<LongWritable, LongWritable, NullWritable> {
+
+    @Override
+    public TextVertexReader createVertexReader(InputSplit split, TaskAttemptContext context) throws IOException {
+        return new TextVertexReaderFromEachLine() {
+            String[] items;
+
+            @Override
+            protected LongWritable getId(Text line) throws IOException {
+                String[] kv = line.toString().split("\t");
+                items = kv[1].split(" ");
+                return new LongWritable(Long.parseLong(kv[0]));
+            }
+
+            @Override
+            protected LongWritable getValue(Text line) throws IOException {
+                return null;
+            }
+
+            @Override
+            protected Iterable<Edge<LongWritable, NullWritable>> getEdges(Text line) throws IOException {
+                List<Edge<LongWritable, NullWritable>> edges = new ArrayList<Edge<LongWritable, NullWritable>>();
+                Map<LongWritable, NullWritable> edgeMap = new HashMap<LongWritable, NullWritable>();
+                for (int i = 1; i < items.length; i++) {
+                    edgeMap.put(new LongWritable(Long.parseLong(items[i])), null);
+                }
+                for (Entry<LongWritable, NullWritable> entry : edgeMap.entrySet()) {
+                    MapMutableEdge<LongWritable, NullWritable> edge = new MapMutableEdge<LongWritable, NullWritable>();
+                    edge.setEntry(entry);
+                    edge.setValue(null);
+                    edges.add(edge);
+                }
+                return edges;
+            }
+
+        };
+    }
+
+}
diff --git a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/TextPageRankInputFormat.java b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io2/TextPRInputFormat2.java
similarity index 62%
copy from pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/TextPageRankInputFormat.java
copy to pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io2/TextPRInputFormat2.java
index 3d85f66..63a4519 100644
--- a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/TextPageRankInputFormat.java
+++ b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io2/TextPRInputFormat2.java
@@ -12,7 +12,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package edu.uci.ics.pregelix.benchmark;
+package edu.uci.ics.pregelix.benchmark.io2;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -25,13 +25,13 @@
 import org.apache.giraph.edge.MapMutableEdge;
 import org.apache.giraph.io.formats.TextVertexInputFormat;
 import org.apache.hadoop.io.DoubleWritable;
-import org.apache.hadoop.io.FloatWritable;
+import org.apache.hadoop.io.LongWritable;
+import org.apache.hadoop.io.NullWritable;
 import org.apache.hadoop.io.Text;
-import org.apache.hadoop.io.VLongWritable;
 import org.apache.hadoop.mapreduce.InputSplit;
 import org.apache.hadoop.mapreduce.TaskAttemptContext;
 
-public class TextPageRankInputFormat extends TextVertexInputFormat<VLongWritable, DoubleWritable, FloatWritable> {
+public class TextPRInputFormat2 extends TextVertexInputFormat<LongWritable, DoubleWritable, NullWritable> {
 
     @Override
     public TextVertexReader createVertexReader(InputSplit split, TaskAttemptContext context) throws IOException {
@@ -39,9 +39,10 @@
             String[] items;
 
             @Override
-            protected VLongWritable getId(Text line) throws IOException {
-                items = line.toString().split(" ");
-                return new VLongWritable(Long.parseLong(items[0]));
+            protected LongWritable getId(Text line) throws IOException {
+                String[] kv = line.toString().split("\t");
+                items = kv[1].split(" ");
+                return new LongWritable(Long.parseLong(items[0]));
             }
 
             @Override
@@ -50,14 +51,14 @@
             }
 
             @Override
-            protected Iterable<Edge<VLongWritable, FloatWritable>> getEdges(Text line) throws IOException {
-                List<Edge<VLongWritable, FloatWritable>> edges = new ArrayList<Edge<VLongWritable, FloatWritable>>();
-                Map<VLongWritable, FloatWritable> edgeMap = new HashMap<VLongWritable, FloatWritable>();
+            protected Iterable<Edge<LongWritable, NullWritable>> getEdges(Text line) throws IOException {
+                List<Edge<LongWritable, NullWritable>> edges = new ArrayList<Edge<LongWritable, NullWritable>>();
+                Map<LongWritable, NullWritable> edgeMap = new HashMap<LongWritable, NullWritable>();
                 for (int i = 1; i < items.length; i++) {
-                    edgeMap.put(new VLongWritable(Long.parseLong(items[i])), null);
+                    edgeMap.put(new LongWritable(Long.parseLong(items[i])), null);
                 }
-                for (Entry<VLongWritable, FloatWritable> entry : edgeMap.entrySet()) {
-                    MapMutableEdge<VLongWritable, FloatWritable> edge = new MapMutableEdge<VLongWritable, FloatWritable>();
+                for (Entry<LongWritable, NullWritable> entry : edgeMap.entrySet()) {
+                    MapMutableEdge<LongWritable, NullWritable> edge = new MapMutableEdge<LongWritable, NullWritable>();
                     edge.setEntry(entry);
                     edge.setValue(null);
                     edges.add(edge);
diff --git a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/TextPageRankInputFormat.java b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io2/TextSPInputFormat2.java
similarity index 63%
copy from pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/TextPageRankInputFormat.java
copy to pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io2/TextSPInputFormat2.java
index 3d85f66..fdb1061 100644
--- a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/TextPageRankInputFormat.java
+++ b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/io2/TextSPInputFormat2.java
@@ -12,7 +12,8 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package edu.uci.ics.pregelix.benchmark;
+
+package edu.uci.ics.pregelix.benchmark.io2;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -25,13 +26,12 @@
 import org.apache.giraph.edge.MapMutableEdge;
 import org.apache.giraph.io.formats.TextVertexInputFormat;
 import org.apache.hadoop.io.DoubleWritable;
-import org.apache.hadoop.io.FloatWritable;
+import org.apache.hadoop.io.LongWritable;
 import org.apache.hadoop.io.Text;
-import org.apache.hadoop.io.VLongWritable;
 import org.apache.hadoop.mapreduce.InputSplit;
 import org.apache.hadoop.mapreduce.TaskAttemptContext;
 
-public class TextPageRankInputFormat extends TextVertexInputFormat<VLongWritable, DoubleWritable, FloatWritable> {
+public class TextSPInputFormat2 extends TextVertexInputFormat<LongWritable, DoubleWritable, DoubleWritable> {
 
     @Override
     public TextVertexReader createVertexReader(InputSplit split, TaskAttemptContext context) throws IOException {
@@ -39,9 +39,10 @@
             String[] items;
 
             @Override
-            protected VLongWritable getId(Text line) throws IOException {
-                items = line.toString().split(" ");
-                return new VLongWritable(Long.parseLong(items[0]));
+            protected LongWritable getId(Text line) throws IOException {
+                String[] kv = line.toString().split("\t");
+                items = kv[1].split(" ");
+                return new LongWritable(Long.parseLong(kv[0]));
             }
 
             @Override
@@ -50,16 +51,16 @@
             }
 
             @Override
-            protected Iterable<Edge<VLongWritable, FloatWritable>> getEdges(Text line) throws IOException {
-                List<Edge<VLongWritable, FloatWritable>> edges = new ArrayList<Edge<VLongWritable, FloatWritable>>();
-                Map<VLongWritable, FloatWritable> edgeMap = new HashMap<VLongWritable, FloatWritable>();
+            protected Iterable<Edge<LongWritable, DoubleWritable>> getEdges(Text line) throws IOException {
+                List<Edge<LongWritable, DoubleWritable>> edges = new ArrayList<Edge<LongWritable, DoubleWritable>>();
+                Map<LongWritable, DoubleWritable> edgeMap = new HashMap<LongWritable, DoubleWritable>();
                 for (int i = 1; i < items.length; i++) {
-                    edgeMap.put(new VLongWritable(Long.parseLong(items[i])), null);
+                    edgeMap.put(new LongWritable(Long.parseLong(items[i])), null);
                 }
-                for (Entry<VLongWritable, FloatWritable> entry : edgeMap.entrySet()) {
-                    MapMutableEdge<VLongWritable, FloatWritable> edge = new MapMutableEdge<VLongWritable, FloatWritable>();
+                for (Entry<LongWritable, DoubleWritable> entry : edgeMap.entrySet()) {
+                    MapMutableEdge<LongWritable, DoubleWritable> edge = new MapMutableEdge<LongWritable, DoubleWritable>();
                     edge.setEntry(entry);
-                    edge.setValue(null);
+                    edge.setValue(new DoubleWritable(1.0));
                     edges.add(edge);
                 }
                 return edges;
@@ -67,4 +68,5 @@
 
         };
     }
+
 }
diff --git a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/vertex/ConnectedComponentsVertex.java b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/vertex/ConnectedComponentsVertex.java
new file mode 100644
index 0000000..3789d6d
--- /dev/null
+++ b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/vertex/ConnectedComponentsVertex.java
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.pregelix.benchmark.vertex;
+
+import java.io.IOException;
+
+import org.apache.giraph.edge.Edge;
+import org.apache.giraph.graph.Vertex;
+import org.apache.hadoop.io.LongWritable;
+import org.apache.hadoop.io.NullWritable;
+
+public class ConnectedComponentsVertex extends Vertex<LongWritable, LongWritable, NullWritable, LongWritable> {
+    /**
+     * Propagates the smallest vertex id to all neighbors. Will always choose to
+     * halt and only reactivate if a smaller id has been sent to it.
+     * 
+     * @param messages
+     *            Iterator of messages from the previous superstep.
+     * @throws IOException
+     */
+    @Override
+    public void compute(Iterable<LongWritable> messages) throws IOException {
+        long currentComponent = getValue().get();
+
+        // First superstep is special, because we can simply look at the neighbors
+        if (getSuperstep() == 0) {
+            for (Edge<LongWritable, NullWritable> edge : getEdges()) {
+                long neighbor = edge.getTargetVertexId().get();
+                if (neighbor < currentComponent) {
+                    currentComponent = neighbor;
+                }
+            }
+            // Only need to send value if it is not the own id
+            if (currentComponent != getValue().get()) {
+                setValue(new LongWritable(currentComponent));
+                for (Edge<LongWritable, NullWritable> edge : getEdges()) {
+                    LongWritable neighbor = edge.getTargetVertexId();
+                    if (neighbor.get() > currentComponent) {
+                        sendMessage(neighbor, getValue());
+                    }
+                }
+            }
+
+            voteToHalt();
+            return;
+        }
+
+        boolean changed = false;
+        // did we get a smaller id ?
+        for (LongWritable message : messages) {
+            long candidateComponent = message.get();
+            if (candidateComponent < currentComponent) {
+                currentComponent = candidateComponent;
+                changed = true;
+            }
+        }
+
+        // propagate new component id to the neighbors
+        if (changed) {
+            setValue(new LongWritable(currentComponent));
+            sendMessageToAllEdges(getValue());
+        }
+        voteToHalt();
+    }
+}
diff --git a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/vertex/PageRankVertex.java b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/vertex/PageRankVertex.java
new file mode 100644
index 0000000..86e90dd
--- /dev/null
+++ b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/vertex/PageRankVertex.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.pregelix.benchmark.vertex;
+
+import org.apache.giraph.edge.Edge;
+import org.apache.giraph.examples.RandomWalkVertex;
+import org.apache.giraph.utils.MathUtils;
+import org.apache.hadoop.io.DoubleWritable;
+import org.apache.hadoop.io.LongWritable;
+import org.apache.hadoop.io.NullWritable;
+
+/**
+ * The PageRank algorithm, with uniform transition probabilities on the edges
+ * http://en.wikipedia.org/wiki/PageRank
+ */
+public class PageRankVertex extends RandomWalkVertex<NullWritable> {
+
+    @Override
+    protected double transitionProbability(double stateProbability, Edge<LongWritable, NullWritable> edge) {
+        return stateProbability / getNumEdges();
+    }
+
+    @Override
+    protected double recompute(Iterable<DoubleWritable> partialRanks, double teleportationProbability) {
+
+        // rank contribution from incident neighbors
+        double rankFromNeighbors = MathUtils.sum(partialRanks);
+        // rank contribution from dangling vertices
+        double danglingContribution = getDanglingProbability() / getTotalNumVertices();
+
+        // recompute rank
+        return (1d - teleportationProbability) * (rankFromNeighbors + danglingContribution) + teleportationProbability
+                / getTotalNumVertices();
+    }
+}
diff --git a/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/vertex/ShortestPathsVertex.java b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/vertex/ShortestPathsVertex.java
new file mode 100644
index 0000000..755a3d0
--- /dev/null
+++ b/pregelix/pregelix-benchmark/src/main/java/edu/uci/ics/pregelix/benchmark/vertex/ShortestPathsVertex.java
@@ -0,0 +1,62 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.pregelix.benchmark.vertex;
+
+import java.io.IOException;
+
+import org.apache.giraph.edge.Edge;
+import org.apache.giraph.graph.Vertex;
+import org.apache.hadoop.io.DoubleWritable;
+import org.apache.hadoop.io.LongWritable;
+
+/**
+ * Shortest paths algorithm.
+ */
+public class ShortestPathsVertex extends Vertex<LongWritable, DoubleWritable, DoubleWritable, DoubleWritable> {
+    /** Source id. */
+    public static final String SOURCE_ID = "giraph.shortestPathsBenchmark.sourceId";
+    /** Default source id. */
+    public static final long SOURCE_ID_DEFAULT = 1;
+
+    private boolean isSource() {
+        return getId().get() == getConf().getLong(SOURCE_ID, SOURCE_ID_DEFAULT);
+    }
+
+    @Override
+    public void compute(Iterable<DoubleWritable> messages) throws IOException {
+        if (getSuperstep() == 0) {
+            setValue(new DoubleWritable(Double.MAX_VALUE));
+        }
+
+        double minDist = isSource() ? 0d : Double.MAX_VALUE;
+        for (DoubleWritable message : messages) {
+            minDist = Math.min(minDist, message.get());
+        }
+
+        if (minDist < getValue().get()) {
+            setValue(new DoubleWritable(minDist));
+            for (Edge<LongWritable, DoubleWritable> edge : getEdges()) {
+                double distance = minDist + edge.getValue().get();
+                sendMessage(edge.getTargetVertexId(), new DoubleWritable(distance));
+            }
+        }
+
+        voteToHalt();
+    }
+}
diff --git a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGen.java b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGen.java
index a577bdb..8d9eeac 100644
--- a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGen.java
+++ b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGen.java
@@ -37,7 +37,6 @@
 import org.apache.hadoop.io.NullWritable;
 import org.apache.hadoop.io.Writable;
 import org.apache.hadoop.io.WritableComparable;
-import org.apache.hadoop.io.WritableComparator;
 import org.apache.hadoop.mapreduce.InputFormat;
 import org.apache.hadoop.mapreduce.InputSplit;
 import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
@@ -65,6 +64,7 @@
 import edu.uci.ics.hyracks.dataflow.std.file.FileSplit;
 import edu.uci.ics.hyracks.dataflow.std.file.IFileSplitProvider;
 import edu.uci.ics.hyracks.dataflow.std.misc.ConstantTupleSourceOperatorDescriptor;
+import edu.uci.ics.hyracks.dataflow.std.sort.Algorithm;
 import edu.uci.ics.hyracks.dataflow.std.sort.ExternalSortOperatorDescriptor;
 import edu.uci.ics.hyracks.hdfs2.dataflow.HDFSReadOperatorDescriptor;
 import edu.uci.ics.hyracks.storage.am.btree.dataflow.BTreeDataflowHelperFactory;
@@ -97,7 +97,6 @@
 import edu.uci.ics.pregelix.core.data.TypeTraits;
 import edu.uci.ics.pregelix.core.hadoop.config.ConfigurationFactory;
 import edu.uci.ics.pregelix.core.jobgen.clusterconfig.ClusterConfig;
-import edu.uci.ics.pregelix.core.runtime.touchpoint.WritableComparingBinaryComparatorFactory;
 import edu.uci.ics.pregelix.core.util.DataflowUtils;
 import edu.uci.ics.pregelix.dataflow.ClearStateOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.EmptySinkOperatorDescriptor;
@@ -132,7 +131,7 @@
     protected PregelixJob pregelixJob;
     protected IIndexLifecycleManagerProvider lcManagerProvider = IndexLifeCycleManagerProvider.INSTANCE;
     protected IStorageManagerInterface storageManagerInterface = StorageManagerInterface.INSTANCE;
-    protected String jobId = new UUID(System.currentTimeMillis(), System.nanoTime()).toString();
+    protected String jobId = UUID.randomUUID().toString();
     protected int frameSize = ClusterConfig.getFrameSize();
     protected int maxFrameNumber = (int) (((long) 32 * MB) / frameSize);
 
@@ -204,7 +203,6 @@
         return jobId;
     }
 
-    @SuppressWarnings({ "rawtypes", "unchecked" })
     @Override
     public JobSpecification generateCreatingJob() throws HyracksException {
         Class<? extends WritableComparable<?>> vertexIdClass = BspUtils.getVertexIndexClass(conf);
@@ -213,8 +211,7 @@
         typeTraits[0] = new TypeTraits(false);
         typeTraits[1] = new TypeTraits(false);
         IBinaryComparatorFactory[] comparatorFactories = new IBinaryComparatorFactory[1];
-        comparatorFactories[0] = new WritableComparingBinaryComparatorFactory(WritableComparator.get(vertexIdClass)
-                .getClass());
+        comparatorFactories[0] = JobGenUtil.getIBinaryComparatorFactory(0, vertexIdClass);
 
         int[] keyFields = new int[1];
         keyFields[0] = 0;
@@ -257,7 +254,7 @@
         } catch (Exception e) {
             throw new HyracksDataException(e);
         }
-        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), vertexClass.getName());
         IConfigurationFactory confFactory = new ConfigurationFactory(conf);
         String[] readSchedule = ClusterConfig.getHdfsScheduler().getLocationConstraints(splits);
@@ -272,8 +269,7 @@
         sortFields[0] = 0;
         INormalizedKeyComputerFactory nkmFactory = JobGenUtil.getINormalizedKeyComputerFactory(conf);
         IBinaryComparatorFactory[] comparatorFactories = new IBinaryComparatorFactory[1];
-        comparatorFactories[0] = new WritableComparingBinaryComparatorFactory(WritableComparator.get(vertexIdClass)
-                .getClass());
+        comparatorFactories[0] = JobGenUtil.getIBinaryComparatorFactory(0, vertexIdClass);;
         ExternalSortOperatorDescriptor sorter = new ExternalSortOperatorDescriptor(spec, maxFrameLimit, sortFields,
                 nkmFactory, comparatorFactories, recordDescriptor);
         ClusterConfig.setLocationConstraint(spec, sorter);
@@ -287,7 +283,7 @@
         IFileSplitProvider resultFileSplitProvider = new ConstantFileSplitProvider(results);
         IRuntimeHookFactory preHookFactory = new RuntimeHookFactory(confFactory);
         IRecordDescriptorFactory inputRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
-                vertexIdClass.getName(), vertexClass.getName());
+                conf, vertexIdClass.getName(), vertexClass.getName());
         VertexWriteOperatorDescriptor writer = new VertexWriteOperatorDescriptor(spec, inputRdFactory,
                 resultFileSplitProvider, preHookFactory, null);
         PartitionConstraintHelper.addAbsoluteLocationConstraint(spec, writer, new String[] { "nc1" });
@@ -299,12 +295,12 @@
         ITuplePartitionComputerFactory hashPartitionComputerFactory = getVertexPartitionComputerFactory();
         spec.connect(new OneToOneConnectorDescriptor(spec), scanner, 0, sorter, 0);
         spec.connect(new MToNPartitioningMergingConnectorDescriptor(spec, hashPartitionComputerFactory, sortFields,
-                comparatorFactories), sorter, 0, writer, 0);
+                comparatorFactories, nkmFactory), sorter, 0, writer, 0);
         spec.setFrameSize(frameSize);
         return spec;
     }
 
-    @SuppressWarnings({ "rawtypes", "unchecked" })
+    @SuppressWarnings({ "rawtypes" })
     public JobSpecification scanIndexPrintGraph(String nodeName, String path) throws HyracksException {
         Class<? extends WritableComparable<?>> vertexIdClass = BspUtils.getVertexIndexClass(conf);
         Class<? extends Writable> vertexClass = BspUtils.getVertexClass(conf);
@@ -329,11 +325,10 @@
          * construct btree search operator
          */
         IConfigurationFactory confFactory = new ConfigurationFactory(conf);
-        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), vertexClass.getName());
         IBinaryComparatorFactory[] comparatorFactories = new IBinaryComparatorFactory[1];
-        comparatorFactories[0] = new WritableComparingBinaryComparatorFactory(WritableComparator.get(vertexIdClass)
-                .getClass());
+        comparatorFactories[0] = JobGenUtil.getIBinaryComparatorFactory(0, vertexIdClass);;
         IFileSplitProvider fileSplitProvider = ClusterConfig.getFileSplitProvider(jobId, PRIMARY_INDEX);
         ITypeTraits[] typeTraits = new ITypeTraits[2];
         typeTraits[0] = new TypeTraits(false);
@@ -352,7 +347,7 @@
         IFileSplitProvider resultFileSplitProvider = new ConstantFileSplitProvider(results);
         IRuntimeHookFactory preHookFactory = new RuntimeHookFactory(confFactory);
         IRecordDescriptorFactory inputRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
-                vertexIdClass.getName(), vertexClass.getName());
+                conf, vertexIdClass.getName(), vertexClass.getName());
         VertexWriteOperatorDescriptor writer = new VertexWriteOperatorDescriptor(spec, inputRdFactory,
                 resultFileSplitProvider, preHookFactory, null);
         PartitionConstraintHelper.addAbsoluteLocationConstraint(spec, writer, new String[] { "nc1" });
@@ -363,16 +358,17 @@
          */
         int[] sortFields = new int[1];
         sortFields[0] = 0;
+        INormalizedKeyComputerFactory nkmFactory = JobGenUtil.getINormalizedKeyComputerFactory(conf);
         ITuplePartitionComputerFactory hashPartitionComputerFactory = getVertexPartitionComputerFactory();
         spec.connect(new OneToOneConnectorDescriptor(spec), emptyTupleSource, 0, scanner, 0);
         spec.connect(new MToNPartitioningMergingConnectorDescriptor(spec, hashPartitionComputerFactory, sortFields,
-                comparatorFactories), scanner, 0, writer, 0);
+                comparatorFactories, nkmFactory), scanner, 0, writer, 0);
         spec.setFrameSize(frameSize);
         return spec;
     }
 
     public JobSpecification scanIndexWriteGraph() throws HyracksException {
-        JobSpecification spec = scanIndexWriteToHDFS(conf);
+        JobSpecification spec = scanIndexWriteToHDFS(conf, false);
         return spec;
     }
 
@@ -388,7 +384,7 @@
             FileSystem dfs = FileSystem.get(tmpJob.getConfiguration());
 
             dfs.delete(new Path(BspUtils.getVertexCheckpointPath(conf, lastSuccessfulIteration)), true);
-            JobSpecification vertexCkpSpec = scanIndexWriteToHDFS(tmpJob.getConfiguration());
+            JobSpecification vertexCkpSpec = scanIndexWriteToHDFS(tmpJob.getConfiguration(), true);
 
             dfs.delete(new Path(BspUtils.getMessageCheckpointPath(conf, lastSuccessfulIteration)), true);
             JobSpecification[] stateCkpSpecs = generateStateCheckpointing(lastSuccessfulIteration);
@@ -482,7 +478,7 @@
             return new VertexPartitionComputerFactory(confFactory);
         } else {
             return new VertexIdPartitionComputerFactory(new WritableSerializerDeserializerFactory(
-                    BspUtils.getVertexIndexClass(conf)));
+                    BspUtils.getVertexIndexClass(conf)), confFactory);
         }
     }
 
@@ -518,7 +514,7 @@
         } catch (Exception e) {
             throw new HyracksDataException(e);
         }
-        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), vertexClass.getName());
         IConfigurationFactory confFactory = new ConfigurationFactory(conf);
         String[] readSchedule = ClusterConfig.getHdfsScheduler().getLocationConstraints(splits);
@@ -533,8 +529,7 @@
         sortFields[0] = 0;
         INormalizedKeyComputerFactory nkmFactory = JobGenUtil.getINormalizedKeyComputerFactory(conf);
         IBinaryComparatorFactory[] comparatorFactories = new IBinaryComparatorFactory[1];
-        comparatorFactories[0] = new WritableComparingBinaryComparatorFactory(WritableComparator.get(vertexIdClass)
-                .getClass());
+        comparatorFactories[0] = JobGenUtil.getIBinaryComparatorFactory(0, vertexIdClass);;
         ExternalSortOperatorDescriptor sorter = new ExternalSortOperatorDescriptor(spec, maxFrameNumber, sortFields,
                 nkmFactory, comparatorFactories, recordDescriptor);
         ClusterConfig.setLocationConstraint(spec, sorter);
@@ -564,8 +559,9 @@
         return spec;
     }
 
-    @SuppressWarnings({ "rawtypes", "unchecked" })
-    private JobSpecification scanIndexWriteToHDFS(Configuration conf) throws HyracksDataException, HyracksException {
+    @SuppressWarnings({ "rawtypes" })
+    private JobSpecification scanIndexWriteToHDFS(Configuration conf, boolean ckpointing) throws HyracksDataException,
+            HyracksException {
         Class<? extends WritableComparable<?>> vertexIdClass = BspUtils.getVertexIndexClass(conf);
         Class<? extends Writable> vertexClass = BspUtils.getVertexClass(conf);
         JobSpecification spec = new JobSpecification();
@@ -589,11 +585,10 @@
          * construct btree search operator
          */
         IConfigurationFactory confFactory = new ConfigurationFactory(conf);
-        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), vertexClass.getName());
         IBinaryComparatorFactory[] comparatorFactories = new IBinaryComparatorFactory[1];
-        comparatorFactories[0] = new WritableComparingBinaryComparatorFactory(WritableComparator.get(vertexIdClass)
-                .getClass());
+        comparatorFactories[0] = JobGenUtil.getIBinaryComparatorFactory(0, vertexIdClass);;
         IFileSplitProvider fileSplitProvider = ClusterConfig.getFileSplitProvider(jobId, PRIMARY_INDEX);
 
         ITypeTraits[] typeTraits = new ITypeTraits[2];
@@ -605,20 +600,37 @@
                 null, null, true, true, getIndexDataflowHelperFactory(), false, NoOpOperationCallbackFactory.INSTANCE);
         ClusterConfig.setLocationConstraint(spec, scanner);
 
+        ExternalSortOperatorDescriptor sort = null;
+        if (!ckpointing) {
+            int[] keyFields = new int[] { 0 };
+            INormalizedKeyComputerFactory nkmFactory = JobGenUtil.getFinalNormalizedKeyComputerFactory(conf);
+            IBinaryComparatorFactory[] sortCmpFactories = new IBinaryComparatorFactory[1];
+            sortCmpFactories[0] = JobGenUtil.getFinalBinaryComparatorFactory(vertexIdClass);
+            sort = new ExternalSortOperatorDescriptor(spec, maxFrameNumber, keyFields, nkmFactory, sortCmpFactories,
+                    recordDescriptor);
+            ClusterConfig.setLocationConstraint(spec, scanner);
+        }
+
         /**
          * construct write file operator
          */
+        IRuntimeHookFactory preHookFactory = new RuntimeHookFactory(confFactory);
         IRecordDescriptorFactory inputRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
-                vertexIdClass.getName(), vertexClass.getName());
+                conf, vertexIdClass.getName(), vertexClass.getName());
         VertexFileWriteOperatorDescriptor writer = new VertexFileWriteOperatorDescriptor(spec, confFactory,
-                inputRdFactory);
+                inputRdFactory, preHookFactory);
         ClusterConfig.setLocationConstraint(spec, writer);
 
         /**
          * connect operator descriptors
          */
         spec.connect(new OneToOneConnectorDescriptor(spec), emptyTupleSource, 0, scanner, 0);
-        spec.connect(new OneToOneConnectorDescriptor(spec), scanner, 0, writer, 0);
+        if (!ckpointing) {
+            spec.connect(new OneToOneConnectorDescriptor(spec), scanner, 0, sort, 0);
+            spec.connect(new OneToOneConnectorDescriptor(spec), sort, 0, writer, 0);
+        } else {
+            spec.connect(new OneToOneConnectorDescriptor(spec), scanner, 0, writer, 0);
+        }
         spec.setFrameSize(frameSize);
         return spec;
     }
@@ -645,7 +657,7 @@
         /**
          * source aggregate
          */
-        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
+        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf, vertexIdClass.getName(),
                 MsgList.class.getName());
 
         /**
@@ -658,7 +670,7 @@
          * construct the materializing write operator
          */
         MaterializingReadOperatorDescriptor materializeRead = new MaterializingReadOperatorDescriptor(spec, rdFinal,
-                false);
+                false, jobId, lastSuccessfulIteration + 1);
         ClusterConfig.setLocationConstraint(spec, materializeRead);
 
         String checkpointPath = BspUtils.getMessageCheckpointPath(conf, lastSuccessfulIteration);;
@@ -669,7 +681,7 @@
         tmpJob.setOutputValueClass(MsgList.class);
 
         IRecordDescriptorFactory inputRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
-                vertexIdClass.getName(), MsgList.class.getName());
+                conf, vertexIdClass.getName(), MsgList.class.getName());
         HDFSFileWriteOperatorDescriptor hdfsWriter = new HDFSFileWriteOperatorDescriptor(spec, tmpJob, inputRdFactory);
         ClusterConfig.setLocationConstraint(spec, hdfsWriter);
 
@@ -709,7 +721,7 @@
         } catch (Exception e) {
             throw new HyracksDataException(e);
         }
-        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), MsgList.class.getName());
         String[] readSchedule = ClusterConfig.getHdfsScheduler().getLocationConstraints(splits);
         HDFSReadOperatorDescriptor scanner = new HDFSReadOperatorDescriptor(spec, recordDescriptor, tmpJob, splits,
@@ -720,17 +732,16 @@
         int[] keyFields = new int[] { 0 };
         INormalizedKeyComputerFactory nkmFactory = JobGenUtil.getINormalizedKeyComputerFactory(conf);
         IBinaryComparatorFactory[] sortCmpFactories = new IBinaryComparatorFactory[1];
-        sortCmpFactories[0] = JobGenUtil.getIBinaryComparatorFactory(lastCheckpointedIteration,
-                WritableComparator.get(vertexIdClass).getClass());
+        sortCmpFactories[0] = JobGenUtil.getIBinaryComparatorFactory(lastCheckpointedIteration, vertexIdClass);
         ExternalSortOperatorDescriptor sort = new ExternalSortOperatorDescriptor(spec, maxFrameNumber, keyFields,
-                nkmFactory, sortCmpFactories, recordDescriptor);
+                nkmFactory, sortCmpFactories, recordDescriptor, Algorithm.QUICK_SORT);
         ClusterConfig.setLocationConstraint(spec, sort);
 
         /**
          * construct the materializing write operator
          */
         MaterializingWriteOperatorDescriptor materialize = new MaterializingWriteOperatorDescriptor(spec,
-                recordDescriptor);
+                recordDescriptor, jobId, lastCheckpointedIteration);
         ClusterConfig.setLocationConstraint(spec, materialize);
 
         /** construct runtime hook */
diff --git a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenInnerJoin.java b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenInnerJoin.java
index 9389f62..9fefbea 100644
--- a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenInnerJoin.java
+++ b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenInnerJoin.java
@@ -50,6 +50,7 @@
 import edu.uci.ics.hyracks.dataflow.std.connectors.OneToOneConnectorDescriptor;
 import edu.uci.ics.hyracks.dataflow.std.file.IFileSplitProvider;
 import edu.uci.ics.hyracks.dataflow.std.misc.ConstantTupleSourceOperatorDescriptor;
+import edu.uci.ics.hyracks.dataflow.std.sort.Algorithm;
 import edu.uci.ics.hyracks.dataflow.std.sort.ExternalSortOperatorDescriptor;
 import edu.uci.ics.hyracks.hdfs2.dataflow.HDFSReadOperatorDescriptor;
 import edu.uci.ics.hyracks.storage.am.btree.dataflow.BTreeSearchOperatorDescriptor;
@@ -62,7 +63,6 @@
 import edu.uci.ics.pregelix.core.data.TypeTraits;
 import edu.uci.ics.pregelix.core.hadoop.config.ConfigurationFactory;
 import edu.uci.ics.pregelix.core.jobgen.clusterconfig.ClusterConfig;
-import edu.uci.ics.pregelix.core.runtime.touchpoint.WritableComparingBinaryComparatorFactory;
 import edu.uci.ics.pregelix.core.util.DataflowUtils;
 import edu.uci.ics.pregelix.dataflow.ConnectorPolicyAssignmentPolicy;
 import edu.uci.ics.pregelix.dataflow.EmptySinkOperatorDescriptor;
@@ -97,7 +97,6 @@
         super(job);
     }
 
-    @SuppressWarnings({ "rawtypes", "unchecked" })
     protected JobSpecification generateFirstIteration(int iteration) throws HyracksException {
         Class<? extends WritableComparable<?>> vertexIdClass = BspUtils.getVertexIndexClass(conf);
         Class<? extends Writable> vertexClass = BspUtils.getVertexClass(conf);
@@ -126,30 +125,30 @@
         /**
          * construct btree search and function call update operator
          */
-        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), vertexClass.getName());
         IBinaryComparatorFactory[] comparatorFactories = new IBinaryComparatorFactory[1];
-        comparatorFactories[0] = new WritableComparingBinaryComparatorFactory(WritableComparator.get(vertexIdClass)
-                .getClass());
+        comparatorFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, vertexIdClass);
 
         ITypeTraits[] typeTraits = new ITypeTraits[2];
         typeTraits[0] = new TypeTraits(false);
         typeTraits[1] = new TypeTraits(false);
 
-        RecordDescriptor rdDummy = DataflowUtils.getRecordDescriptorFromWritableClasses(VLongWritable.class.getName());
-        RecordDescriptor rdPartialAggregate = DataflowUtils
-                .getRecordDescriptorFromWritableClasses(partialAggregateValueClass.getName());
+        RecordDescriptor rdDummy = DataflowUtils.getRecordDescriptorFromWritableClasses(conf,
+                VLongWritable.class.getName());
+        RecordDescriptor rdPartialAggregate = DataflowUtils.getRecordDescriptorFromWritableClasses(conf,
+                partialAggregateValueClass.getName());
         IConfigurationFactory configurationFactory = new ConfigurationFactory(conf);
         IRuntimeHookFactory preHookFactory = new RuntimeHookFactory(configurationFactory);
         IRecordDescriptorFactory inputRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
-                vertexIdClass.getName(), vertexClass.getName());
-        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
+                conf, vertexIdClass.getName(), vertexClass.getName());
+        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf, vertexIdClass.getName(),
                 MsgList.class.getName());
-        RecordDescriptor rdUnnestedMessage = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+        RecordDescriptor rdUnnestedMessage = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), messageValueClass.getName());
-        RecordDescriptor rdInsert = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
+        RecordDescriptor rdInsert = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf, vertexIdClass.getName(),
                 vertexClass.getName());
-        RecordDescriptor rdDelete = DataflowUtils.getRecordDescriptorFromWritableClasses(vertexIdClass.getName());
+        RecordDescriptor rdDelete = DataflowUtils.getRecordDescriptorFromWritableClasses(conf, vertexIdClass.getName());
 
         TreeSearchFunctionUpdateOperatorDescriptor scanner = new TreeSearchFunctionUpdateOperatorDescriptor(spec,
                 recordDescriptor, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits,
@@ -168,8 +167,8 @@
         /**
          * final aggregate write operator
          */
-        IRecordDescriptorFactory aggRdFactory = DataflowUtils
-                .getWritableRecordDescriptorFactoryFromWritableClasses(partialAggregateValueClass.getName());
+        IRecordDescriptorFactory aggRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
+                conf, partialAggregateValueClass.getName());
         FinalAggregateOperatorDescriptor finalAggregator = new FinalAggregateOperatorDescriptor(spec,
                 configurationFactory, aggRdFactory, jobId);
         PartitionConstraintHelper.addPartitionCountConstraint(spec, finalAggregator, 1);
@@ -195,7 +194,7 @@
         sortCmpFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, WritableComparator.get(vertexIdClass)
                 .getClass());
         ExternalSortOperatorDescriptor localSort = new ExternalSortOperatorDescriptor(spec, maxFrameNumber, keyFields,
-                nkmFactory, sortCmpFactories, rdUnnestedMessage);
+                nkmFactory, sortCmpFactories, rdUnnestedMessage, Algorithm.QUICK_SORT);
         ClusterConfig.setLocationConstraint(spec, localSort);
 
         /**
@@ -219,7 +218,8 @@
         /**
          * construct the materializing write operator
          */
-        MaterializingWriteOperatorDescriptor materialize = new MaterializingWriteOperatorDescriptor(spec, rdFinal);
+        MaterializingWriteOperatorDescriptor materialize = new MaterializingWriteOperatorDescriptor(spec, rdFinal,
+                jobId, iteration);
         ClusterConfig.setLocationConstraint(spec, materialize);
 
         /**
@@ -282,8 +282,8 @@
 
         spec.connect(new MToNPartitioningConnectorDescriptor(spec, partionFactory), scanner, 5, btreeBulkLoad, 0);
         spec.connect(new OneToOneConnectorDescriptor(spec), localSort, 0, localGby, 0);
-        spec.connect(new MToNPartitioningMergingConnectorDescriptor(spec, partionFactory, keyFields, sortCmpFactories),
-                localGby, 0, globalGby, 0);
+        spec.connect(new MToNPartitioningMergingConnectorDescriptor(spec, partionFactory, keyFields, sortCmpFactories,
+                nkmFactory), localGby, 0, globalGby, 0);
         spec.connect(new OneToOneConnectorDescriptor(spec), globalGby, 0, materialize, 0);
         spec.connect(new OneToOneConnectorDescriptor(spec), materialize, 0, postSuperStep, 0);
         spec.connect(new OneToOneConnectorDescriptor(spec), postSuperStep, 0, emptySink, 0);
@@ -300,7 +300,6 @@
         return spec;
     }
 
-    @SuppressWarnings({ "rawtypes", "unchecked" })
     @Override
     protected JobSpecification generateNonFirstIteration(int iteration) throws HyracksException {
         Class<? extends WritableComparable<?>> vertexIdClass = BspUtils.getVertexIndexClass(conf);
@@ -313,16 +312,15 @@
          * source aggregate
          */
         int[] keyFields = new int[] { 0 };
-        RecordDescriptor rdUnnestedMessage = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+        RecordDescriptor rdUnnestedMessage = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), messageValueClass.getName());
         IBinaryComparatorFactory[] comparatorFactories = new IBinaryComparatorFactory[1];
-        comparatorFactories[0] = new WritableComparingBinaryComparatorFactory(WritableComparator.get(vertexIdClass)
-                .getClass());
-        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
+        comparatorFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, vertexIdClass);;
+        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf, vertexIdClass.getName(),
                 MsgList.class.getName());
-        RecordDescriptor rdInsert = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
+        RecordDescriptor rdInsert = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf, vertexIdClass.getName(),
                 vertexClass.getName());
-        RecordDescriptor rdDelete = DataflowUtils.getRecordDescriptorFromWritableClasses(vertexIdClass.getName());
+        RecordDescriptor rdDelete = DataflowUtils.getRecordDescriptorFromWritableClasses(conf, vertexIdClass.getName());
 
         /**
          * construct empty tuple operator
@@ -342,7 +340,7 @@
          * construct the materializing write operator
          */
         MaterializingReadOperatorDescriptor materializeRead = new MaterializingReadOperatorDescriptor(spec, rdFinal,
-                true);
+                true, jobId, iteration);
         ClusterConfig.setLocationConstraint(spec, materializeRead);
 
         /**
@@ -363,13 +361,14 @@
          * construct index-join-function-update operator
          */
         IFileSplitProvider fileSplitProvider = ClusterConfig.getFileSplitProvider(jobId, PRIMARY_INDEX);
-        RecordDescriptor rdDummy = DataflowUtils.getRecordDescriptorFromWritableClasses(VLongWritable.class.getName());
-        RecordDescriptor rdPartialAggregate = DataflowUtils
-                .getRecordDescriptorFromWritableClasses(partialAggregateValueClass.getName());
+        RecordDescriptor rdDummy = DataflowUtils.getRecordDescriptorFromWritableClasses(conf,
+                VLongWritable.class.getName());
+        RecordDescriptor rdPartialAggregate = DataflowUtils.getRecordDescriptorFromWritableClasses(conf,
+                partialAggregateValueClass.getName());
         IConfigurationFactory configurationFactory = new ConfigurationFactory(conf);
         IRuntimeHookFactory preHookFactory = new RuntimeHookFactory(configurationFactory);
         IRecordDescriptorFactory inputRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
-                vertexIdClass.getName(), MsgList.class.getName(), vertexIdClass.getName(), vertexClass.getName());
+                conf, vertexIdClass.getName(), MsgList.class.getName(), vertexIdClass.getName(), vertexClass.getName());
 
         IndexNestedLoopJoinFunctionUpdateOperatorDescriptor join = new IndexNestedLoopJoinFunctionUpdateOperatorDescriptor(
                 spec, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits, comparatorFactories,
@@ -401,7 +400,7 @@
         sortCmpFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, WritableComparator.get(vertexIdClass)
                 .getClass());
         ExternalSortOperatorDescriptor localSort = new ExternalSortOperatorDescriptor(spec, maxFrameNumber, keyFields,
-                nkmFactory, sortCmpFactories, rdUnnestedMessage);
+                nkmFactory, sortCmpFactories, rdUnnestedMessage, Algorithm.QUICK_SORT);
         ClusterConfig.setLocationConstraint(spec, localSort);
 
         /**
@@ -425,7 +424,8 @@
         /**
          * construct the materializing write operator
          */
-        MaterializingWriteOperatorDescriptor materialize = new MaterializingWriteOperatorDescriptor(spec, rdFinal);
+        MaterializingWriteOperatorDescriptor materialize = new MaterializingWriteOperatorDescriptor(spec, rdFinal,
+                jobId, iteration);
         ClusterConfig.setLocationConstraint(spec, materialize);
 
         /** construct runtime hook */
@@ -447,8 +447,8 @@
         /**
          * final aggregate write operator
          */
-        IRecordDescriptorFactory aggRdFactory = DataflowUtils
-                .getWritableRecordDescriptorFactoryFromWritableClasses(partialAggregateValueClass.getName());
+        IRecordDescriptorFactory aggRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
+                conf, partialAggregateValueClass.getName());
         FinalAggregateOperatorDescriptor finalAggregator = new FinalAggregateOperatorDescriptor(spec,
                 configurationFactory, aggRdFactory, jobId);
         PartitionConstraintHelper.addPartitionCountConstraint(spec, finalAggregator, 1);
@@ -503,8 +503,8 @@
 
         spec.connect(new MToNPartitioningConnectorDescriptor(spec, partionFactory), join, 5, btreeBulkLoad, 0);
         spec.connect(new OneToOneConnectorDescriptor(spec), localSort, 0, localGby, 0);
-        spec.connect(new MToNPartitioningMergingConnectorDescriptor(spec, partionFactory, keyFields, sortCmpFactories),
-                localGby, 0, globalGby, 0);
+        spec.connect(new MToNPartitioningMergingConnectorDescriptor(spec, partionFactory, keyFields, sortCmpFactories,
+                nkmFactory), localGby, 0, globalGby, 0);
         spec.connect(new OneToOneConnectorDescriptor(spec), globalGby, 0, materialize, 0);
         spec.connect(new OneToOneConnectorDescriptor(spec), materialize, 0, postSuperStep, 0);
         spec.connect(new OneToOneConnectorDescriptor(spec), postSuperStep, 0, emptySink, 0);
@@ -587,7 +587,7 @@
         } catch (Exception e) {
             throw new HyracksDataException(e);
         }
-        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), MsgList.class.getName());
         String[] readSchedule = ClusterConfig.getHdfsScheduler().getLocationConstraints(splits);
         HDFSReadOperatorDescriptor scanner = new HDFSReadOperatorDescriptor(spec, recordDescriptor, tmpJob, splits,
@@ -598,10 +598,9 @@
         int[] keyFields = new int[] { 0 };
         INormalizedKeyComputerFactory nkmFactory = JobGenUtil.getINormalizedKeyComputerFactory(conf);
         IBinaryComparatorFactory[] sortCmpFactories = new IBinaryComparatorFactory[1];
-        sortCmpFactories[0] = JobGenUtil.getIBinaryComparatorFactory(lastSuccessfulIteration,
-                WritableComparator.get(vertexIdClass).getClass());
+        sortCmpFactories[0] = JobGenUtil.getIBinaryComparatorFactory(lastSuccessfulIteration, vertexIdClass);
         ExternalSortOperatorDescriptor sort = new ExternalSortOperatorDescriptor(spec, maxFrameNumber, keyFields,
-                nkmFactory, sortCmpFactories, recordDescriptor);
+                nkmFactory, sortCmpFactories, recordDescriptor, Algorithm.QUICK_SORT);
         ClusterConfig.setLocationConstraint(spec, sort);
 
         /**
@@ -633,7 +632,7 @@
         return spec;
     }
 
-    @SuppressWarnings({ "rawtypes", "unchecked" })
+    @SuppressWarnings({ "rawtypes" })
     private JobSpecification generateSecondaryBTreeCheckpoint(int lastSuccessfulIteration, PregelixJob job)
             throws HyracksException {
         job.setOutputFormatClass(SequenceFileOutputFormat.class);
@@ -665,11 +664,10 @@
         /**
          * construct btree search operator
          */
-        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), msgListClass.getName());
         IBinaryComparatorFactory[] comparatorFactories = new IBinaryComparatorFactory[1];
-        comparatorFactories[0] = new WritableComparingBinaryComparatorFactory(WritableComparator.get(vertexIdClass)
-                .getClass());
+        comparatorFactories[0] = JobGenUtil.getIBinaryComparatorFactory(0, vertexIdClass);;
 
         ITypeTraits[] typeTraits = new ITypeTraits[2];
         typeTraits[0] = new TypeTraits(false);
@@ -685,7 +683,7 @@
          * construct write file operator
          */
         IRecordDescriptorFactory inputRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
-                vertexIdClass.getName(), MsgList.class.getName());
+                conf, vertexIdClass.getName(), MsgList.class.getName());
         HDFSFileWriteOperatorDescriptor writer = new HDFSFileWriteOperatorDescriptor(spec, job, inputRdFactory);
         ClusterConfig.setLocationConstraint(spec, writer);
 
diff --git a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenOuterJoin.java b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenOuterJoin.java
index 287b797..ee576b1 100644
--- a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenOuterJoin.java
+++ b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenOuterJoin.java
@@ -17,7 +17,6 @@
 import org.apache.hadoop.io.VLongWritable;
 import org.apache.hadoop.io.Writable;
 import org.apache.hadoop.io.WritableComparable;
-import org.apache.hadoop.io.WritableComparator;
 
 import edu.uci.ics.hyracks.api.constraints.PartitionConstraintHelper;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
@@ -32,6 +31,7 @@
 import edu.uci.ics.hyracks.dataflow.std.connectors.MToNPartitioningMergingConnectorDescriptor;
 import edu.uci.ics.hyracks.dataflow.std.connectors.OneToOneConnectorDescriptor;
 import edu.uci.ics.hyracks.dataflow.std.file.IFileSplitProvider;
+import edu.uci.ics.hyracks.dataflow.std.sort.Algorithm;
 import edu.uci.ics.hyracks.dataflow.std.sort.ExternalSortOperatorDescriptor;
 import edu.uci.ics.hyracks.storage.am.common.dataflow.TreeIndexInsertUpdateDeleteOperatorDescriptor;
 import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallbackFactory;
@@ -42,7 +42,6 @@
 import edu.uci.ics.pregelix.core.data.TypeTraits;
 import edu.uci.ics.pregelix.core.hadoop.config.ConfigurationFactory;
 import edu.uci.ics.pregelix.core.jobgen.clusterconfig.ClusterConfig;
-import edu.uci.ics.pregelix.core.runtime.touchpoint.WritableComparingBinaryComparatorFactory;
 import edu.uci.ics.pregelix.core.util.DataflowUtils;
 import edu.uci.ics.pregelix.dataflow.ConnectorPolicyAssignmentPolicy;
 import edu.uci.ics.pregelix.dataflow.EmptySinkOperatorDescriptor;
@@ -74,7 +73,6 @@
         super(job);
     }
 
-    @SuppressWarnings({ "rawtypes", "unchecked" })
     @Override
     protected JobSpecification generateFirstIteration(int iteration) throws HyracksException {
         Class<? extends WritableComparable<?>> vertexIdClass = BspUtils.getVertexIndexClass(conf);
@@ -98,29 +96,29 @@
         /**
          * construct btree search function update operator
          */
-        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), vertexClass.getName());
         IBinaryComparatorFactory[] comparatorFactories = new IBinaryComparatorFactory[1];
-        comparatorFactories[0] = new WritableComparingBinaryComparatorFactory(WritableComparator.get(vertexIdClass)
-                .getClass());
+        comparatorFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, vertexIdClass);;
         IFileSplitProvider fileSplitProvider = ClusterConfig.getFileSplitProvider(jobId, PRIMARY_INDEX);
 
         ITypeTraits[] typeTraits = new ITypeTraits[2];
         typeTraits[0] = new TypeTraits(false);
         typeTraits[1] = new TypeTraits(false);
 
-        RecordDescriptor rdDummy = DataflowUtils.getRecordDescriptorFromWritableClasses(VLongWritable.class.getName());
-        RecordDescriptor rdPartialAggregate = DataflowUtils
-                .getRecordDescriptorFromWritableClasses(partialAggregateValueClass.getName());
+        RecordDescriptor rdDummy = DataflowUtils.getRecordDescriptorFromWritableClasses(conf,
+                VLongWritable.class.getName());
+        RecordDescriptor rdPartialAggregate = DataflowUtils.getRecordDescriptorFromWritableClasses(conf,
+                partialAggregateValueClass.getName());
         IConfigurationFactory configurationFactory = new ConfigurationFactory(conf);
         IRuntimeHookFactory preHookFactory = new RuntimeHookFactory(configurationFactory);
         IRecordDescriptorFactory inputRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
-                vertexIdClass.getName(), vertexClass.getName());
-        RecordDescriptor rdUnnestedMessage = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+                conf, vertexIdClass.getName(), vertexClass.getName());
+        RecordDescriptor rdUnnestedMessage = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), messageValueClass.getName());
-        RecordDescriptor rdInsert = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
+        RecordDescriptor rdInsert = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf, vertexIdClass.getName(),
                 vertexClass.getName());
-        RecordDescriptor rdDelete = DataflowUtils.getRecordDescriptorFromWritableClasses(vertexIdClass.getName());
+        RecordDescriptor rdDelete = DataflowUtils.getRecordDescriptorFromWritableClasses(conf, vertexIdClass.getName());
 
         TreeSearchFunctionUpdateOperatorDescriptor scanner = new TreeSearchFunctionUpdateOperatorDescriptor(spec,
                 recordDescriptor, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits,
@@ -135,10 +133,9 @@
         int[] keyFields = new int[] { 0 };
         INormalizedKeyComputerFactory nkmFactory = JobGenUtil.getINormalizedKeyComputerFactory(conf);
         IBinaryComparatorFactory[] sortCmpFactories = new IBinaryComparatorFactory[1];
-        sortCmpFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, WritableComparator.get(vertexIdClass)
-                .getClass());
+        sortCmpFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, vertexIdClass);
         ExternalSortOperatorDescriptor localSort = new ExternalSortOperatorDescriptor(spec, maxFrameNumber, keyFields,
-                nkmFactory, sortCmpFactories, rdUnnestedMessage);
+                nkmFactory, sortCmpFactories, rdUnnestedMessage, Algorithm.QUICK_SORT);
         ClusterConfig.setLocationConstraint(spec, localSort);
 
         /**
@@ -153,7 +150,7 @@
         /**
          * construct global group-by operator
          */
-        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
+        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf, vertexIdClass.getName(),
                 MsgList.class.getName());
         IClusteredAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(
                 conf, true, true);
@@ -164,7 +161,8 @@
         /**
          * construct the materializing write operator
          */
-        MaterializingWriteOperatorDescriptor materialize = new MaterializingWriteOperatorDescriptor(spec, rdFinal);
+        MaterializingWriteOperatorDescriptor materialize = new MaterializingWriteOperatorDescriptor(spec, rdFinal,
+                jobId, iteration);
         ClusterConfig.setLocationConstraint(spec, materialize);
 
         RuntimeHookOperatorDescriptor postSuperStep = new RuntimeHookOperatorDescriptor(spec,
@@ -186,8 +184,8 @@
         /**
          * final aggregate write operator
          */
-        IRecordDescriptorFactory aggRdFactory = DataflowUtils
-                .getWritableRecordDescriptorFactoryFromWritableClasses(partialAggregateValueClass.getName());
+        IRecordDescriptorFactory aggRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
+                conf, partialAggregateValueClass.getName());
         FinalAggregateOperatorDescriptor finalAggregator = new FinalAggregateOperatorDescriptor(spec,
                 configurationFactory, aggRdFactory, jobId);
         PartitionConstraintHelper.addPartitionCountConstraint(spec, finalAggregator, 1);
@@ -241,8 +239,8 @@
          * connect the group-by operator
          */
         spec.connect(new OneToOneConnectorDescriptor(spec), localSort, 0, localGby, 0);
-        spec.connect(new MToNPartitioningMergingConnectorDescriptor(spec, partionFactory, keyFields, sortCmpFactories),
-                localGby, 0, globalGby, 0);
+        spec.connect(new MToNPartitioningMergingConnectorDescriptor(spec, partionFactory, keyFields, sortCmpFactories,
+                nkmFactory), localGby, 0, globalGby, 0);
         spec.connect(new OneToOneConnectorDescriptor(spec), globalGby, 0, materialize, 0);
         spec.connect(new OneToOneConnectorDescriptor(spec), materialize, 0, postSuperStep, 0);
         spec.connect(new OneToOneConnectorDescriptor(spec), postSuperStep, 0, emptySink2, 0);
@@ -258,7 +256,6 @@
         return spec;
     }
 
-    @SuppressWarnings({ "rawtypes", "unchecked" })
     @Override
     protected JobSpecification generateNonFirstIteration(int iteration) throws HyracksException {
         Class<? extends WritableComparable<?>> vertexIdClass = BspUtils.getVertexIndexClass(conf);
@@ -271,16 +268,15 @@
          * source aggregate
          */
         int[] keyFields = new int[] { 0 };
-        RecordDescriptor rdUnnestedMessage = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+        RecordDescriptor rdUnnestedMessage = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), messageValueClass.getName());
         IBinaryComparatorFactory[] comparatorFactories = new IBinaryComparatorFactory[1];
-        comparatorFactories[0] = new WritableComparingBinaryComparatorFactory(WritableComparator.get(vertexIdClass)
-                .getClass());
-        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
+        comparatorFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, vertexIdClass);
+        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf, vertexIdClass.getName(),
                 MsgList.class.getName());
-        RecordDescriptor rdInsert = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
+        RecordDescriptor rdInsert = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf, vertexIdClass.getName(),
                 vertexClass.getName());
-        RecordDescriptor rdDelete = DataflowUtils.getRecordDescriptorFromWritableClasses(vertexIdClass.getName());
+        RecordDescriptor rdDelete = DataflowUtils.getRecordDescriptorFromWritableClasses(conf, vertexIdClass.getName());
 
         /**
          * construct empty tuple operator
@@ -300,7 +296,7 @@
          * construct the materializing write operator
          */
         MaterializingReadOperatorDescriptor materializeRead = new MaterializingReadOperatorDescriptor(spec, rdFinal,
-                true);
+                true, jobId, iteration);
         ClusterConfig.setLocationConstraint(spec, materializeRead);
 
         /**
@@ -314,13 +310,14 @@
         nullWriterFactories[0] = VertexIdNullWriterFactory.INSTANCE;
         nullWriterFactories[1] = MsgListNullWriterFactory.INSTANCE;
 
-        RecordDescriptor rdDummy = DataflowUtils.getRecordDescriptorFromWritableClasses(VLongWritable.class.getName());
-        RecordDescriptor rdPartialAggregate = DataflowUtils
-                .getRecordDescriptorFromWritableClasses(partialAggregateValueClass.getName());
+        RecordDescriptor rdDummy = DataflowUtils.getRecordDescriptorFromWritableClasses(conf,
+                VLongWritable.class.getName());
+        RecordDescriptor rdPartialAggregate = DataflowUtils.getRecordDescriptorFromWritableClasses(conf,
+                partialAggregateValueClass.getName());
         IConfigurationFactory configurationFactory = new ConfigurationFactory(conf);
         IRuntimeHookFactory preHookFactory = new RuntimeHookFactory(configurationFactory);
         IRecordDescriptorFactory inputRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
-                vertexIdClass.getName(), MsgList.class.getName(), vertexIdClass.getName(), vertexClass.getName());
+                conf, vertexIdClass.getName(), MsgList.class.getName(), vertexIdClass.getName(), vertexClass.getName());
 
         IndexNestedLoopJoinFunctionUpdateOperatorDescriptor join = new IndexNestedLoopJoinFunctionUpdateOperatorDescriptor(
                 spec, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits, comparatorFactories,
@@ -335,10 +332,9 @@
          */
         INormalizedKeyComputerFactory nkmFactory = JobGenUtil.getINormalizedKeyComputerFactory(conf);
         IBinaryComparatorFactory[] sortCmpFactories = new IBinaryComparatorFactory[1];
-        sortCmpFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, WritableComparator.get(vertexIdClass)
-                .getClass());
+        sortCmpFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, vertexIdClass);
         ExternalSortOperatorDescriptor localSort = new ExternalSortOperatorDescriptor(spec, maxFrameNumber, keyFields,
-                nkmFactory, sortCmpFactories, rdUnnestedMessage);
+                nkmFactory, sortCmpFactories, rdUnnestedMessage, Algorithm.QUICK_SORT);
         ClusterConfig.setLocationConstraint(spec, localSort);
 
         /**
@@ -362,7 +358,8 @@
         /**
          * construct the materializing write operator
          */
-        MaterializingWriteOperatorDescriptor materialize = new MaterializingWriteOperatorDescriptor(spec, rdFinal);
+        MaterializingWriteOperatorDescriptor materialize = new MaterializingWriteOperatorDescriptor(spec, rdFinal,
+                jobId, iteration);
         ClusterConfig.setLocationConstraint(spec, materialize);
 
         /** construct runtime hook */
@@ -384,8 +381,8 @@
         /**
          * final aggregate write operator
          */
-        IRecordDescriptorFactory aggRdFactory = DataflowUtils
-                .getWritableRecordDescriptorFactoryFromWritableClasses(partialAggregateValueClass.getName());
+        IRecordDescriptorFactory aggRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
+                conf, partialAggregateValueClass.getName());
         FinalAggregateOperatorDescriptor finalAggregator = new FinalAggregateOperatorDescriptor(spec,
                 configurationFactory, aggRdFactory, jobId);
         PartitionConstraintHelper.addPartitionCountConstraint(spec, finalAggregator, 1);
@@ -440,8 +437,8 @@
         spec.connect(new OneToOneConnectorDescriptor(spec), deleteOp, 0, emptySink4, 0);
 
         spec.connect(new OneToOneConnectorDescriptor(spec), localSort, 0, localGby, 0);
-        spec.connect(new MToNPartitioningMergingConnectorDescriptor(spec, partionFactory, keyFields, sortCmpFactories),
-                localGby, 0, globalGby, 0);
+        spec.connect(new MToNPartitioningMergingConnectorDescriptor(spec, partionFactory, keyFields, sortCmpFactories,
+                nkmFactory), localGby, 0, globalGby, 0);
         spec.connect(new OneToOneConnectorDescriptor(spec), globalGby, 0, materialize, 0);
         spec.connect(new OneToOneConnectorDescriptor(spec), materialize, 0, postSuperStep, 0);
         spec.connect(new OneToOneConnectorDescriptor(spec), postSuperStep, 0, emptySink, 0);
diff --git a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenOuterJoinSingleSort.java b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenOuterJoinSingleSort.java
index 3b3c9e7..32271c8 100644
--- a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenOuterJoinSingleSort.java
+++ b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenOuterJoinSingleSort.java
@@ -31,6 +31,7 @@
 import edu.uci.ics.hyracks.dataflow.std.connectors.MToNPartitioningConnectorDescriptor;
 import edu.uci.ics.hyracks.dataflow.std.connectors.OneToOneConnectorDescriptor;
 import edu.uci.ics.hyracks.dataflow.std.file.IFileSplitProvider;
+import edu.uci.ics.hyracks.dataflow.std.sort.Algorithm;
 import edu.uci.ics.hyracks.dataflow.std.sort.ExternalSortOperatorDescriptor;
 import edu.uci.ics.hyracks.storage.am.common.dataflow.TreeIndexInsertUpdateDeleteOperatorDescriptor;
 import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallbackFactory;
@@ -41,7 +42,6 @@
 import edu.uci.ics.pregelix.core.data.TypeTraits;
 import edu.uci.ics.pregelix.core.hadoop.config.ConfigurationFactory;
 import edu.uci.ics.pregelix.core.jobgen.clusterconfig.ClusterConfig;
-import edu.uci.ics.pregelix.core.runtime.touchpoint.WritableComparingBinaryComparatorFactory;
 import edu.uci.ics.pregelix.core.util.DataflowUtils;
 import edu.uci.ics.pregelix.dataflow.ConnectorPolicyAssignmentPolicy;
 import edu.uci.ics.pregelix.dataflow.EmptySinkOperatorDescriptor;
@@ -73,7 +73,6 @@
         super(job);
     }
 
-    @SuppressWarnings({ "rawtypes", "unchecked" })
     @Override
     protected JobSpecification generateFirstIteration(int iteration) throws HyracksException {
         Class<? extends WritableComparable<?>> vertexIdClass = BspUtils.getVertexIndexClass(conf);
@@ -97,11 +96,10 @@
         /**
          * construct btree search operator
          */
-        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), vertexClass.getName());
         IBinaryComparatorFactory[] comparatorFactories = new IBinaryComparatorFactory[1];
-        comparatorFactories[0] = new WritableComparingBinaryComparatorFactory(WritableComparator.get(vertexIdClass)
-                .getClass());
+        comparatorFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, vertexIdClass);
         IFileSplitProvider fileSplitProvider = ClusterConfig.getFileSplitProvider(jobId, PRIMARY_INDEX);
 
         ITypeTraits[] typeTraits = new ITypeTraits[2];
@@ -111,18 +109,19 @@
         /**
          * construct compute operator
          */
-        RecordDescriptor rdDummy = DataflowUtils.getRecordDescriptorFromWritableClasses(VLongWritable.class.getName());
-        RecordDescriptor rdPartialAggregate = DataflowUtils
-                .getRecordDescriptorFromWritableClasses(partialAggregateValueClass.getName());
+        RecordDescriptor rdDummy = DataflowUtils.getRecordDescriptorFromWritableClasses(conf,
+                VLongWritable.class.getName());
+        RecordDescriptor rdPartialAggregate = DataflowUtils.getRecordDescriptorFromWritableClasses(conf,
+                partialAggregateValueClass.getName());
         IConfigurationFactory configurationFactory = new ConfigurationFactory(conf);
         IRuntimeHookFactory preHookFactory = new RuntimeHookFactory(configurationFactory);
         IRecordDescriptorFactory inputRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
-                vertexIdClass.getName(), vertexClass.getName());
-        RecordDescriptor rdUnnestedMessage = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+                conf, vertexIdClass.getName(), vertexClass.getName());
+        RecordDescriptor rdUnnestedMessage = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), messageValueClass.getName());
-        RecordDescriptor rdInsert = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
+        RecordDescriptor rdInsert = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf, vertexIdClass.getName(),
                 vertexClass.getName());
-        RecordDescriptor rdDelete = DataflowUtils.getRecordDescriptorFromWritableClasses(vertexIdClass.getName());
+        RecordDescriptor rdDelete = DataflowUtils.getRecordDescriptorFromWritableClasses(conf, vertexIdClass.getName());
 
         TreeSearchFunctionUpdateOperatorDescriptor scanner = new TreeSearchFunctionUpdateOperatorDescriptor(spec,
                 recordDescriptor, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits,
@@ -140,13 +139,13 @@
         sortCmpFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, WritableComparator.get(vertexIdClass)
                 .getClass());
         ExternalSortOperatorDescriptor globalSort = new ExternalSortOperatorDescriptor(spec, maxFrameNumber, keyFields,
-                nkmFactory, sortCmpFactories, rdUnnestedMessage);
+                nkmFactory, sortCmpFactories, rdUnnestedMessage, Algorithm.QUICK_SORT);
         ClusterConfig.setLocationConstraint(spec, globalSort);
 
         /**
          * construct global group-by operator
          */
-        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
+        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf, vertexIdClass.getName(),
                 MsgList.class.getName());
         IClusteredAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(
                 conf, true, false);
@@ -157,7 +156,8 @@
         /**
          * construct the materializing write operator
          */
-        MaterializingWriteOperatorDescriptor materialize = new MaterializingWriteOperatorDescriptor(spec, rdFinal);
+        MaterializingWriteOperatorDescriptor materialize = new MaterializingWriteOperatorDescriptor(spec, rdFinal,
+                jobId, iteration);
         ClusterConfig.setLocationConstraint(spec, materialize);
 
         RuntimeHookOperatorDescriptor postSuperStep = new RuntimeHookOperatorDescriptor(spec,
@@ -178,8 +178,8 @@
         /**
          * final aggregate write operator
          */
-        IRecordDescriptorFactory aggRdFactory = DataflowUtils
-                .getWritableRecordDescriptorFactoryFromWritableClasses(partialAggregateValueClass.getName());
+        IRecordDescriptorFactory aggRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
+                conf, partialAggregateValueClass.getName());
         FinalAggregateOperatorDescriptor finalAggregator = new FinalAggregateOperatorDescriptor(spec,
                 configurationFactory, aggRdFactory, jobId);
         PartitionConstraintHelper.addPartitionCountConstraint(spec, finalAggregator, 1);
@@ -247,7 +247,6 @@
         return spec;
     }
 
-    @SuppressWarnings({ "rawtypes", "unchecked" })
     @Override
     protected JobSpecification generateNonFirstIteration(int iteration) throws HyracksException {
         Class<? extends WritableComparable<?>> vertexIdClass = BspUtils.getVertexIndexClass(conf);
@@ -260,16 +259,15 @@
          * source aggregate
          */
         int[] keyFields = new int[] { 0 };
-        RecordDescriptor rdUnnestedMessage = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+        RecordDescriptor rdUnnestedMessage = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), messageValueClass.getName());
         IBinaryComparatorFactory[] comparatorFactories = new IBinaryComparatorFactory[1];
-        comparatorFactories[0] = new WritableComparingBinaryComparatorFactory(WritableComparator.get(vertexIdClass)
-                .getClass());
-        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
+        comparatorFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, vertexIdClass);
+        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf, vertexIdClass.getName(),
                 MsgList.class.getName());
-        RecordDescriptor rdInsert = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
+        RecordDescriptor rdInsert = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf, vertexIdClass.getName(),
                 vertexClass.getName());
-        RecordDescriptor rdDelete = DataflowUtils.getRecordDescriptorFromWritableClasses(vertexIdClass.getName());
+        RecordDescriptor rdDelete = DataflowUtils.getRecordDescriptorFromWritableClasses(conf, vertexIdClass.getName());
 
         /**
          * construct empty tuple operator
@@ -289,7 +287,7 @@
          * construct the materializing write operator
          */
         MaterializingReadOperatorDescriptor materializeRead = new MaterializingReadOperatorDescriptor(spec, rdFinal,
-                true);
+                true, jobId, iteration);
         ClusterConfig.setLocationConstraint(spec, materializeRead);
 
         /**
@@ -303,13 +301,14 @@
         nullWriterFactories[0] = VertexIdNullWriterFactory.INSTANCE;
         nullWriterFactories[1] = MsgListNullWriterFactory.INSTANCE;
 
-        RecordDescriptor rdDummy = DataflowUtils.getRecordDescriptorFromWritableClasses(VLongWritable.class.getName());
-        RecordDescriptor rdPartialAggregate = DataflowUtils
-                .getRecordDescriptorFromWritableClasses(partialAggregateValueClass.getName());
+        RecordDescriptor rdDummy = DataflowUtils.getRecordDescriptorFromWritableClasses(conf,
+                VLongWritable.class.getName());
+        RecordDescriptor rdPartialAggregate = DataflowUtils.getRecordDescriptorFromWritableClasses(conf,
+                partialAggregateValueClass.getName());
         IConfigurationFactory configurationFactory = new ConfigurationFactory(conf);
         IRuntimeHookFactory preHookFactory = new RuntimeHookFactory(configurationFactory);
         IRecordDescriptorFactory inputRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
-                vertexIdClass.getName(), MsgList.class.getName(), vertexIdClass.getName(), vertexClass.getName());
+                conf, vertexIdClass.getName(), MsgList.class.getName(), vertexIdClass.getName(), vertexClass.getName());
 
         IndexNestedLoopJoinFunctionUpdateOperatorDescriptor join = new IndexNestedLoopJoinFunctionUpdateOperatorDescriptor(
                 spec, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits, comparatorFactories,
@@ -327,7 +326,7 @@
         sortCmpFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, WritableComparator.get(vertexIdClass)
                 .getClass());
         ExternalSortOperatorDescriptor globalSort = new ExternalSortOperatorDescriptor(spec, maxFrameNumber, keyFields,
-                nkmFactory, sortCmpFactories, rdUnnestedMessage);
+                nkmFactory, sortCmpFactories, rdUnnestedMessage, Algorithm.QUICK_SORT);
         ClusterConfig.setLocationConstraint(spec, globalSort);
 
         /**
@@ -342,7 +341,8 @@
         /**
          * construct the materializing write operator
          */
-        MaterializingWriteOperatorDescriptor materialize = new MaterializingWriteOperatorDescriptor(spec, rdFinal);
+        MaterializingWriteOperatorDescriptor materialize = new MaterializingWriteOperatorDescriptor(spec, rdFinal,
+                jobId, iteration);
         ClusterConfig.setLocationConstraint(spec, materialize);
 
         /** construct runtime hook */
@@ -364,8 +364,8 @@
         /**
          * final aggregate write operator
          */
-        IRecordDescriptorFactory aggRdFactory = DataflowUtils
-                .getWritableRecordDescriptorFactoryFromWritableClasses(partialAggregateValueClass.getName());
+        IRecordDescriptorFactory aggRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
+                conf, partialAggregateValueClass.getName());
         FinalAggregateOperatorDescriptor finalAggregator = new FinalAggregateOperatorDescriptor(spec,
                 configurationFactory, aggRdFactory, jobId);
         PartitionConstraintHelper.addPartitionCountConstraint(spec, finalAggregator, 1);
diff --git a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenOuterJoinSort.java b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenOuterJoinSort.java
index e334095..3aa36cd 100644
--- a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenOuterJoinSort.java
+++ b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenOuterJoinSort.java
@@ -31,6 +31,7 @@
 import edu.uci.ics.hyracks.dataflow.std.connectors.MToNPartitioningConnectorDescriptor;
 import edu.uci.ics.hyracks.dataflow.std.connectors.OneToOneConnectorDescriptor;
 import edu.uci.ics.hyracks.dataflow.std.file.IFileSplitProvider;
+import edu.uci.ics.hyracks.dataflow.std.sort.Algorithm;
 import edu.uci.ics.hyracks.dataflow.std.sort.ExternalSortOperatorDescriptor;
 import edu.uci.ics.hyracks.storage.am.common.dataflow.TreeIndexInsertUpdateDeleteOperatorDescriptor;
 import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallbackFactory;
@@ -41,7 +42,6 @@
 import edu.uci.ics.pregelix.core.data.TypeTraits;
 import edu.uci.ics.pregelix.core.hadoop.config.ConfigurationFactory;
 import edu.uci.ics.pregelix.core.jobgen.clusterconfig.ClusterConfig;
-import edu.uci.ics.pregelix.core.runtime.touchpoint.WritableComparingBinaryComparatorFactory;
 import edu.uci.ics.pregelix.core.util.DataflowUtils;
 import edu.uci.ics.pregelix.dataflow.ConnectorPolicyAssignmentPolicy;
 import edu.uci.ics.pregelix.dataflow.EmptySinkOperatorDescriptor;
@@ -73,7 +73,6 @@
         super(job);
     }
 
-    @SuppressWarnings({ "rawtypes", "unchecked" })
     @Override
     protected JobSpecification generateFirstIteration(int iteration) throws HyracksException {
         Class<? extends WritableComparable<?>> vertexIdClass = BspUtils.getVertexIndexClass(conf);
@@ -97,29 +96,29 @@
         /**
          * construct btree search function update operator
          */
-        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+        RecordDescriptor recordDescriptor = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), vertexClass.getName());
         IBinaryComparatorFactory[] comparatorFactories = new IBinaryComparatorFactory[1];
-        comparatorFactories[0] = new WritableComparingBinaryComparatorFactory(WritableComparator.get(vertexIdClass)
-                .getClass());
+        comparatorFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, vertexIdClass);
         IFileSplitProvider fileSplitProvider = ClusterConfig.getFileSplitProvider(jobId, PRIMARY_INDEX);
 
         ITypeTraits[] typeTraits = new ITypeTraits[2];
         typeTraits[0] = new TypeTraits(false);
         typeTraits[1] = new TypeTraits(false);
 
-        RecordDescriptor rdDummy = DataflowUtils.getRecordDescriptorFromWritableClasses(VLongWritable.class.getName());
-        RecordDescriptor rdPartialAggregate = DataflowUtils
-                .getRecordDescriptorFromWritableClasses(partialAggregateValueClass.getName());
+        RecordDescriptor rdDummy = DataflowUtils.getRecordDescriptorFromWritableClasses(conf,
+                VLongWritable.class.getName());
+        RecordDescriptor rdPartialAggregate = DataflowUtils.getRecordDescriptorFromWritableClasses(conf,
+                partialAggregateValueClass.getName());
         IConfigurationFactory configurationFactory = new ConfigurationFactory(conf);
         IRuntimeHookFactory preHookFactory = new RuntimeHookFactory(configurationFactory);
         IRecordDescriptorFactory inputRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
-                vertexIdClass.getName(), vertexClass.getName());
-        RecordDescriptor rdUnnestedMessage = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+                conf, vertexIdClass.getName(), vertexClass.getName());
+        RecordDescriptor rdUnnestedMessage = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), messageValueClass.getName());
-        RecordDescriptor rdInsert = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
+        RecordDescriptor rdInsert = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf, vertexIdClass.getName(),
                 vertexClass.getName());
-        RecordDescriptor rdDelete = DataflowUtils.getRecordDescriptorFromWritableClasses(vertexIdClass.getName());
+        RecordDescriptor rdDelete = DataflowUtils.getRecordDescriptorFromWritableClasses(conf, vertexIdClass.getName());
 
         TreeSearchFunctionUpdateOperatorDescriptor scanner = new TreeSearchFunctionUpdateOperatorDescriptor(spec,
                 recordDescriptor, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits,
@@ -137,7 +136,7 @@
         sortCmpFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, WritableComparator.get(vertexIdClass)
                 .getClass());
         ExternalSortOperatorDescriptor localSort = new ExternalSortOperatorDescriptor(spec, maxFrameNumber, keyFields,
-                nkmFactory, sortCmpFactories, rdUnnestedMessage);
+                nkmFactory, sortCmpFactories, rdUnnestedMessage, Algorithm.QUICK_SORT);
         ClusterConfig.setLocationConstraint(spec, localSort);
 
         /**
@@ -153,13 +152,13 @@
          * construct global sort operator
          */
         ExternalSortOperatorDescriptor globalSort = new ExternalSortOperatorDescriptor(spec, maxFrameNumber, keyFields,
-                nkmFactory, sortCmpFactories, rdUnnestedMessage);
+                nkmFactory, sortCmpFactories, rdUnnestedMessage, Algorithm.QUICK_SORT);
         ClusterConfig.setLocationConstraint(spec, globalSort);
 
         /**
          * construct global group-by operator
          */
-        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
+        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf, vertexIdClass.getName(),
                 MsgList.class.getName());
         IClusteredAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(
                 conf, true, true);
@@ -170,7 +169,8 @@
         /**
          * construct the materializing write operator
          */
-        MaterializingWriteOperatorDescriptor materialize = new MaterializingWriteOperatorDescriptor(spec, rdFinal);
+        MaterializingWriteOperatorDescriptor materialize = new MaterializingWriteOperatorDescriptor(spec, rdFinal,
+                jobId, iteration);
         ClusterConfig.setLocationConstraint(spec, materialize);
 
         RuntimeHookOperatorDescriptor postSuperStep = new RuntimeHookOperatorDescriptor(spec,
@@ -192,8 +192,8 @@
         /**
          * final aggregate write operator
          */
-        IRecordDescriptorFactory aggRdFactory = DataflowUtils
-                .getWritableRecordDescriptorFactoryFromWritableClasses(partialAggregateValueClass.getName());
+        IRecordDescriptorFactory aggRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
+                conf, partialAggregateValueClass.getName());
         FinalAggregateOperatorDescriptor finalAggregator = new FinalAggregateOperatorDescriptor(spec,
                 configurationFactory, aggRdFactory, jobId);
         PartitionConstraintHelper.addPartitionCountConstraint(spec, finalAggregator, 1);
@@ -261,7 +261,6 @@
         return spec;
     }
 
-    @SuppressWarnings({ "rawtypes", "unchecked" })
     @Override
     protected JobSpecification generateNonFirstIteration(int iteration) throws HyracksException {
         Class<? extends WritableComparable<?>> vertexIdClass = BspUtils.getVertexIndexClass(conf);
@@ -274,16 +273,15 @@
          * source aggregate
          */
         int[] keyFields = new int[] { 0 };
-        RecordDescriptor rdUnnestedMessage = DataflowUtils.getRecordDescriptorFromKeyValueClasses(
+        RecordDescriptor rdUnnestedMessage = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf,
                 vertexIdClass.getName(), messageValueClass.getName());
         IBinaryComparatorFactory[] comparatorFactories = new IBinaryComparatorFactory[1];
-        comparatorFactories[0] = new WritableComparingBinaryComparatorFactory(WritableComparator.get(vertexIdClass)
-                .getClass());
-        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
+        comparatorFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, vertexIdClass);
+        RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf, vertexIdClass.getName(),
                 MsgList.class.getName());
-        RecordDescriptor rdInsert = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
+        RecordDescriptor rdInsert = DataflowUtils.getRecordDescriptorFromKeyValueClasses(conf, vertexIdClass.getName(),
                 vertexClass.getName());
-        RecordDescriptor rdDelete = DataflowUtils.getRecordDescriptorFromWritableClasses(vertexIdClass.getName());
+        RecordDescriptor rdDelete = DataflowUtils.getRecordDescriptorFromWritableClasses(conf, vertexIdClass.getName());
 
         /**
          * construct empty tuple operator
@@ -303,7 +301,7 @@
          * construct the materializing write operator
          */
         MaterializingReadOperatorDescriptor materializeRead = new MaterializingReadOperatorDescriptor(spec, rdFinal,
-                true);
+                true, jobId, iteration);
         ClusterConfig.setLocationConstraint(spec, materializeRead);
 
         /**
@@ -317,13 +315,14 @@
         nullWriterFactories[0] = VertexIdNullWriterFactory.INSTANCE;
         nullWriterFactories[1] = MsgListNullWriterFactory.INSTANCE;
 
-        RecordDescriptor rdDummy = DataflowUtils.getRecordDescriptorFromWritableClasses(VLongWritable.class.getName());
-        RecordDescriptor rdPartialAggregate = DataflowUtils
-                .getRecordDescriptorFromWritableClasses(partialAggregateValueClass.getName());
+        RecordDescriptor rdDummy = DataflowUtils.getRecordDescriptorFromWritableClasses(conf,
+                VLongWritable.class.getName());
+        RecordDescriptor rdPartialAggregate = DataflowUtils.getRecordDescriptorFromWritableClasses(conf,
+                partialAggregateValueClass.getName());
         IConfigurationFactory configurationFactory = new ConfigurationFactory(conf);
         IRuntimeHookFactory preHookFactory = new RuntimeHookFactory(configurationFactory);
         IRecordDescriptorFactory inputRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
-                vertexIdClass.getName(), MsgList.class.getName(), vertexIdClass.getName(), vertexClass.getName());
+                conf, vertexIdClass.getName(), MsgList.class.getName(), vertexIdClass.getName(), vertexClass.getName());
 
         IndexNestedLoopJoinFunctionUpdateOperatorDescriptor join = new IndexNestedLoopJoinFunctionUpdateOperatorDescriptor(
                 spec, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits, comparatorFactories,
@@ -341,7 +340,7 @@
         sortCmpFactories[0] = JobGenUtil.getIBinaryComparatorFactory(iteration, WritableComparator.get(vertexIdClass)
                 .getClass());
         ExternalSortOperatorDescriptor localSort = new ExternalSortOperatorDescriptor(spec, maxFrameNumber, keyFields,
-                nkmFactory, sortCmpFactories, rdUnnestedMessage);
+                nkmFactory, sortCmpFactories, rdUnnestedMessage, Algorithm.QUICK_SORT);
         ClusterConfig.setLocationConstraint(spec, localSort);
 
         /**
@@ -357,7 +356,7 @@
          * construct global sort operator
          */
         ExternalSortOperatorDescriptor globalSort = new ExternalSortOperatorDescriptor(spec, maxFrameNumber, keyFields,
-                nkmFactory, sortCmpFactories, rdUnnestedMessage);
+                nkmFactory, sortCmpFactories, rdUnnestedMessage, Algorithm.QUICK_SORT);
         ClusterConfig.setLocationConstraint(spec, globalSort);
 
         /**
@@ -372,7 +371,8 @@
         /**
          * construct the materializing write operator
          */
-        MaterializingWriteOperatorDescriptor materialize = new MaterializingWriteOperatorDescriptor(spec, rdFinal);
+        MaterializingWriteOperatorDescriptor materialize = new MaterializingWriteOperatorDescriptor(spec, rdFinal,
+                jobId, iteration);
         ClusterConfig.setLocationConstraint(spec, materialize);
 
         /** construct runtime hook */
@@ -394,8 +394,8 @@
         /**
          * final aggregate write operator
          */
-        IRecordDescriptorFactory aggRdFactory = DataflowUtils
-                .getWritableRecordDescriptorFactoryFromWritableClasses(partialAggregateValueClass.getName());
+        IRecordDescriptorFactory aggRdFactory = DataflowUtils.getWritableRecordDescriptorFactoryFromWritableClasses(
+                conf, partialAggregateValueClass.getName());
         FinalAggregateOperatorDescriptor finalAggregator = new FinalAggregateOperatorDescriptor(spec,
                 configurationFactory, aggRdFactory, jobId);
         PartitionConstraintHelper.addPartitionCountConstraint(spec, finalAggregator, 1);
diff --git a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenUtil.java b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenUtil.java
index c4f54fe..9f2a66d 100644
--- a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenUtil.java
+++ b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGenUtil.java
@@ -16,15 +16,18 @@
 package edu.uci.ics.pregelix.core.jobgen;
 
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.io.WritableComparator;
 
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputerFactory;
 import edu.uci.ics.pregelix.api.graph.NormalizedKeyComputer;
 import edu.uci.ics.pregelix.api.util.BspUtils;
+import edu.uci.ics.pregelix.core.runtime.touchpoint.RawBinaryComparatorFactory;
+import edu.uci.ics.pregelix.core.runtime.touchpoint.RawNormalizedKeyComputerFactory;
 import edu.uci.ics.pregelix.core.runtime.touchpoint.WritableComparingBinaryComparatorFactory;
 import edu.uci.ics.pregelix.runtime.touchpoint.VertexIdNormalizedKeyComputerFactory;
 
-@SuppressWarnings({ "rawtypes", "unchecked" })
+@SuppressWarnings({ "rawtypes" })
 public class JobGenUtil {
 
     /**
@@ -36,11 +39,7 @@
      * @return
      */
     public static INormalizedKeyComputerFactory getINormalizedKeyComputerFactory(Configuration conf) {
-        Class<? extends NormalizedKeyComputer> clazz = BspUtils.getNormalizedKeyComputerClass(conf);
-        if (clazz.equals(NormalizedKeyComputer.class)) {
-            return null;
-        }
-        return new VertexIdNormalizedKeyComputerFactory(clazz);
+        return RawNormalizedKeyComputerFactory.INSTANCE;
     }
 
     /**
@@ -52,7 +51,34 @@
      * @return
      */
     public static IBinaryComparatorFactory getIBinaryComparatorFactory(int iteration, Class keyClass) {
-        return new WritableComparingBinaryComparatorFactory(keyClass);
+        return RawBinaryComparatorFactory.INSTANCE;
+    }
+
+    /**
+     * get normalized key factory for the final output job
+     * 
+     * @param iteration
+     * @param keyClass
+     * @return
+     */
+    public static INormalizedKeyComputerFactory getFinalNormalizedKeyComputerFactory(Configuration conf) {
+        Class<? extends NormalizedKeyComputer> clazz = BspUtils.getNormalizedKeyComputerClass(conf);
+        if (clazz.equals(NormalizedKeyComputer.class)) {
+            return null;
+        }
+        return new VertexIdNormalizedKeyComputerFactory(clazz);
+    }
+
+    /**
+     * get comparator for the final output job
+     * 
+     * @param iteration
+     * @param keyClass
+     * @return
+     */
+    @SuppressWarnings("unchecked")
+    public static IBinaryComparatorFactory getFinalBinaryComparatorFactory(Class vertexIdClass) {
+        return new WritableComparingBinaryComparatorFactory(WritableComparator.get(vertexIdClass).getClass());
     }
 
     /**
diff --git a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/runtime/touchpoint/RawBinaryComparatorFactory.java b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/runtime/touchpoint/RawBinaryComparatorFactory.java
new file mode 100644
index 0000000..c0173ed
--- /dev/null
+++ b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/runtime/touchpoint/RawBinaryComparatorFactory.java
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.pregelix.core.runtime.touchpoint;
+
+import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparator;
+import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
+
+public class RawBinaryComparatorFactory implements IBinaryComparatorFactory {
+
+    private static final long serialVersionUID = 1L;
+    public static IBinaryComparatorFactory INSTANCE = new RawBinaryComparatorFactory();
+
+    private RawBinaryComparatorFactory() {
+    }
+
+    @Override
+    public IBinaryComparator createBinaryComparator() {
+        return new IBinaryComparator() {
+
+            @Override
+            public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
+                int commonLength = Math.min(l1, l2);
+                for (int i = 0; i < commonLength; i++) {
+                    if (b1[s1 + i] != b2[s2 + i]) {
+                        return (b1[s1 + i] & 0xff) - (b2[s2 + i] & 0xff);
+                    }
+                }
+                int difference = l1 - l2;
+                return difference == 0 ? 0 : (difference > 0 ? 1 : -1);
+            }
+
+        };
+    }
+}
diff --git a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/runtime/touchpoint/RawNormalizedKeyComputerFactory.java b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/runtime/touchpoint/RawNormalizedKeyComputerFactory.java
new file mode 100644
index 0000000..6aa4af9
--- /dev/null
+++ b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/runtime/touchpoint/RawNormalizedKeyComputerFactory.java
@@ -0,0 +1,47 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.pregelix.core.runtime.touchpoint;
+
+import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputer;
+import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputerFactory;
+
+public class RawNormalizedKeyComputerFactory implements INormalizedKeyComputerFactory {
+    private static final long serialVersionUID = 1L;
+    public static final INormalizedKeyComputerFactory INSTANCE = new RawNormalizedKeyComputerFactory();
+
+    private RawNormalizedKeyComputerFactory() {
+
+    }
+
+    @Override
+    public INormalizedKeyComputer createNormalizedKeyComputer() {
+        return new INormalizedKeyComputer() {
+
+            @Override
+            public int normalize(byte[] bytes, int start, int length) {
+                int nk = 0;
+                for (int i = 0; i < 4; i++) {
+                    nk <<= 8;
+                    if (i < length) {
+                        nk += (bytes[start + i] & 0xff);
+                    }
+                }
+                return nk;
+            }
+
+        };
+    }
+}
diff --git a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/runtime/touchpoint/WritableRecordDescriptorFactory.java b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/runtime/touchpoint/WritableRecordDescriptorFactory.java
index a67c259..68e3ba7 100644
--- a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/runtime/touchpoint/WritableRecordDescriptorFactory.java
+++ b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/runtime/touchpoint/WritableRecordDescriptorFactory.java
@@ -14,25 +14,32 @@
  */
 package edu.uci.ics.pregelix.core.runtime.touchpoint;
 
+import org.apache.hadoop.conf.Configuration;
+
 import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
 import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.api.exceptions.HyracksException;
+import edu.uci.ics.pregelix.core.hadoop.config.ConfigurationFactory;
 import edu.uci.ics.pregelix.core.util.DataflowUtils;
+import edu.uci.ics.pregelix.dataflow.base.IConfigurationFactory;
 import edu.uci.ics.pregelix.dataflow.std.base.IRecordDescriptorFactory;
 
 public class WritableRecordDescriptorFactory implements IRecordDescriptorFactory {
     private static final long serialVersionUID = 1L;
     private String[] fieldClasses;
+    private IConfigurationFactory confFactory;
 
-    public WritableRecordDescriptorFactory(String... fieldClasses) {
+    public WritableRecordDescriptorFactory(Configuration conf, String... fieldClasses) {
         this.fieldClasses = fieldClasses;
+        this.confFactory = new ConfigurationFactory(conf);
     }
 
     @Override
     public RecordDescriptor createRecordDescriptor(IHyracksTaskContext ctx) throws HyracksDataException {
         try {
-            return DataflowUtils.getRecordDescriptorFromWritableClasses(ctx, fieldClasses);
+            Configuration conf = confFactory.createConfiguration(ctx);
+            return DataflowUtils.getRecordDescriptorFromWritableClasses(ctx, conf, fieldClasses);
         } catch (HyracksException e) {
             throw new HyracksDataException(e);
         }
diff --git a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/util/DataflowUtils.java b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/util/DataflowUtils.java
index 3e01109..3a2241b 100644
--- a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/util/DataflowUtils.java
+++ b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/util/DataflowUtils.java
@@ -38,14 +38,14 @@
     }
 
     @SuppressWarnings("unchecked")
-    public static RecordDescriptor getRecordDescriptorFromKeyValueClasses(String className1, String className2)
-            throws HyracksException {
+    public static RecordDescriptor getRecordDescriptorFromKeyValueClasses(Configuration conf, String className1,
+            String className2) throws HyracksException {
         RecordDescriptor recordDescriptor = null;
         try {
             ClassLoader loader = DataflowUtils.class.getClassLoader();
             recordDescriptor = DatatypeHelper.createKeyValueRecordDescriptor(
                     (Class<? extends Writable>) loader.loadClass(className1),
-                    (Class<? extends Writable>) loader.loadClass(className2));
+                    (Class<? extends Writable>) loader.loadClass(className2), conf);
         } catch (ClassNotFoundException cnfe) {
             throw new HyracksException(cnfe);
         }
@@ -53,15 +53,16 @@
     }
 
     @SuppressWarnings({ "unchecked", "rawtypes" })
-    public static RecordDescriptor getRecordDescriptorFromWritableClasses(String... classNames) throws HyracksException {
+    public static RecordDescriptor getRecordDescriptorFromWritableClasses(Configuration conf, String... classNames)
+            throws HyracksException {
         RecordDescriptor recordDescriptor = null;
         ISerializerDeserializer[] serdes = new ISerializerDeserializer[classNames.length];
         ClassLoader loader = DataflowUtils.class.getClassLoader();
         try {
             int i = 0;
             for (String className : classNames)
-                serdes[i++] = DatatypeHelper.createSerializerDeserializer((Class<? extends Writable>) loader
-                        .loadClass(className));
+                serdes[i++] = DatatypeHelper.createSerializerDeserializer(
+                        (Class<? extends Writable>) loader.loadClass(className), conf);
         } catch (ClassNotFoundException cnfe) {
             throw new HyracksException(cnfe);
         }
@@ -69,9 +70,9 @@
         return recordDescriptor;
     }
 
-    public static IRecordDescriptorFactory getWritableRecordDescriptorFactoryFromWritableClasses(String... classNames)
-            throws HyracksException {
-        IRecordDescriptorFactory rdFactory = new WritableRecordDescriptorFactory(classNames);
+    public static IRecordDescriptorFactory getWritableRecordDescriptorFactoryFromWritableClasses(Configuration conf,
+            String... classNames) throws HyracksException {
+        IRecordDescriptorFactory rdFactory = new WritableRecordDescriptorFactory(conf, classNames);
         return rdFactory;
     }
 
@@ -85,13 +86,13 @@
     }
 
     @SuppressWarnings("unchecked")
-    public static RecordDescriptor getRecordDescriptorFromKeyValueClasses(IHyracksTaskContext ctx, String className1,
-            String className2) throws HyracksException {
+    public static RecordDescriptor getRecordDescriptorFromKeyValueClasses(IHyracksTaskContext ctx, Configuration conf,
+            String className1, String className2) throws HyracksException {
         RecordDescriptor recordDescriptor = null;
         try {
             recordDescriptor = DatatypeHelper.createKeyValueRecordDescriptor((Class<? extends Writable>) ctx
                     .getJobletContext().loadClass(className1), (Class<? extends Writable>) ctx.getJobletContext()
-                    .loadClass(className2));
+                    .loadClass(className2), conf);
         } catch (Exception cnfe) {
             throw new HyracksException(cnfe);
         }
@@ -99,15 +100,17 @@
     }
 
     @SuppressWarnings({ "unchecked", "rawtypes" })
-    public static RecordDescriptor getRecordDescriptorFromWritableClasses(IHyracksTaskContext ctx, String... classNames)
-            throws HyracksException {
+    public static RecordDescriptor getRecordDescriptorFromWritableClasses(IHyracksTaskContext ctx, Configuration conf,
+            String... classNames) throws HyracksException {
         RecordDescriptor recordDescriptor = null;
         ISerializerDeserializer[] serdes = new ISerializerDeserializer[classNames.length];
         try {
             int i = 0;
-            for (String className : classNames)
-                serdes[i++] = DatatypeHelper.createSerializerDeserializer((Class<? extends Writable>) ctx
-                        .getJobletContext().loadClass(className));
+            for (String className : classNames) {
+                Class<? extends Writable> c = (Class<? extends Writable>) ctx.getJobletContext().loadClass(className);
+                serdes[i++] = DatatypeHelper.createSerializerDeserializer(c, conf);
+                //System.out.println("thread " + Thread.currentThread().getId() + " after creating serde " + c.getClassLoader());
+            }
         } catch (Exception cnfe) {
             throw new HyracksException(cnfe);
         }
diff --git a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/util/PregelixHyracksIntegrationUtil.java b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/util/PregelixHyracksIntegrationUtil.java
index aabd4ba..70de9ed 100644
--- a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/util/PregelixHyracksIntegrationUtil.java
+++ b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/util/PregelixHyracksIntegrationUtil.java
@@ -62,7 +62,7 @@
         ccConfig.jobHistorySize = 1;
         ccConfig.profileDumpPeriod = -1;
         ccConfig.heartbeatPeriod = 50;
-        ccConfig.maxHeartbeatLapsePeriods = 15;
+        ccConfig.maxHeartbeatLapsePeriods = 10;
 
         // cluster controller
         cc = new ClusterControllerService(ccConfig);
diff --git a/pregelix/pregelix-core/src/test/java/edu/uci/ics/pregelix/core/join/JoinTest.java b/pregelix/pregelix-core/src/test/java/edu/uci/ics/pregelix/core/join/JoinTest.java
index 4c7f91d..f599996 100644
--- a/pregelix/pregelix-core/src/test/java/edu/uci/ics/pregelix/core/join/JoinTest.java
+++ b/pregelix/pregelix-core/src/test/java/edu/uci/ics/pregelix/core/join/JoinTest.java
@@ -24,6 +24,7 @@
 import edu.uci.ics.hyracks.api.dataflow.IConnectorDescriptor;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryHashFunctionFactory;
+import edu.uci.ics.hyracks.api.dataflow.value.INormalizedKeyComputerFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.INullWriterFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.ISerializerDeserializer;
 import edu.uci.ics.hyracks.api.dataflow.value.ITypeTraits;
@@ -34,6 +35,7 @@
 import edu.uci.ics.hyracks.data.std.accessors.PointableBinaryHashFunctionFactory;
 import edu.uci.ics.hyracks.data.std.primitive.UTF8StringPointable;
 import edu.uci.ics.hyracks.dataflow.common.data.marshalling.UTF8StringSerializerDeserializer;
+import edu.uci.ics.hyracks.dataflow.common.data.normalizers.UTF8StringNormalizedKeyComputerFactory;
 import edu.uci.ics.hyracks.dataflow.common.data.parsers.IValueParserFactory;
 import edu.uci.ics.hyracks.dataflow.common.data.parsers.UTF8StringParserFactory;
 import edu.uci.ics.hyracks.dataflow.common.data.partition.FieldHashPartitionComputerFactory;
@@ -89,6 +91,7 @@
             UTF8StringPointable.FACTORY);
     private IBinaryComparatorFactory stringComparatorFactory = new PointableBinaryComparatorFactory(
             UTF8StringPointable.FACTORY);
+    private INormalizedKeyComputerFactory nmkFactory = new UTF8StringNormalizedKeyComputerFactory();
 
     private void cleanupStores() throws IOException {
         FileUtils.forceMkdir(new File("teststore"));
@@ -211,7 +214,8 @@
         spec.connect(new OneToOneConnectorDescriptor(spec), join, 0, sorter, 0);
         IConnectorDescriptor joinWriterConn = new MToNPartitioningMergingConnectorDescriptor(spec,
                 new FieldHashPartitionComputerFactory(new int[] { 1 },
-                        new IBinaryHashFunctionFactory[] { stringHashFactory }), sortFields, comparatorFactories);
+                        new IBinaryHashFunctionFactory[] { stringHashFactory }), sortFields, comparatorFactories,
+                nmkFactory);
         spec.connect(joinWriterConn, sorter, 0, writer, 0);
 
         spec.addRoot(writer);
@@ -284,8 +288,8 @@
 
         spec.connect(new OneToOneConnectorDescriptor(spec), custScanner, 0, sorter, 0);
         spec.connect(new MToNPartitioningMergingConnectorDescriptor(spec, new FieldHashPartitionComputerFactory(
-                sortFields, new IBinaryHashFunctionFactory[] { stringHashFactory }), sortFields, comparatorFactories),
-                sorter, 0, writer, 0);
+                sortFields, new IBinaryHashFunctionFactory[] { stringHashFactory }), sortFields, comparatorFactories,
+                nmkFactory), sorter, 0, writer, 0);
 
         spec.addRoot(writer);
         runTest(spec);
@@ -368,11 +372,11 @@
 
         spec.connect(new OneToOneConnectorDescriptor(spec), ordScanner, 0, sorter, 0);
         spec.connect(new MToNPartitioningMergingConnectorDescriptor(spec, new FieldHashPartitionComputerFactory(
-                keyFields, new IBinaryHashFunctionFactory[] { stringHashFactory }), sortFields, comparatorFactories),
-                sorter, 0, join, 0);
+                keyFields, new IBinaryHashFunctionFactory[] { stringHashFactory }), sortFields, comparatorFactories,
+                nmkFactory), sorter, 0, join, 0);
         spec.connect(new MToNPartitioningMergingConnectorDescriptor(spec, new FieldHashPartitionComputerFactory(
-                keyFields, new IBinaryHashFunctionFactory[] { stringHashFactory }), sortFields, comparatorFactories),
-                join, 0, writer, 0);
+                keyFields, new IBinaryHashFunctionFactory[] { stringHashFactory }), sortFields, comparatorFactories,
+                nmkFactory), join, 0, writer, 0);
 
         spec.addRoot(writer);
         runTest(spec);
@@ -477,7 +481,8 @@
         spec.connect(new OneToOneConnectorDescriptor(spec), project, 0, sorter, 0);
         IConnectorDescriptor joinWriterConn = new MToNPartitioningMergingConnectorDescriptor(spec,
                 new FieldHashPartitionComputerFactory(new int[] { 9 },
-                        new IBinaryHashFunctionFactory[] { stringHashFactory }), sortFields, comparatorFactories);
+                        new IBinaryHashFunctionFactory[] { stringHashFactory }), sortFields, comparatorFactories,
+                nmkFactory);
         spec.connect(joinWriterConn, sorter, 0, writer, 0);
 
         spec.addRoot(writer);
@@ -573,7 +578,8 @@
         spec.connect(new OneToOneConnectorDescriptor(spec), ordScanner, 0, sorter, 0);
         spec.connect(new MToNPartitioningMergingConnectorDescriptor(spec, new FieldHashPartitionComputerFactory(
                 keyFields, new IBinaryHashFunctionFactory[] { new PointableBinaryHashFunctionFactory(
-                        UTF8StringPointable.FACTORY) }), sortFields, comparatorFactories), sorter, 0, join, 0);
+                        UTF8StringPointable.FACTORY) }), sortFields, comparatorFactories, nmkFactory), sorter, 0, join,
+                0);
 
         IBinaryComparatorFactory[] mergeComparatorFactories = new IBinaryComparatorFactory[2];
         mergeComparatorFactories[0] = new PointableBinaryComparatorFactory(UTF8StringPointable.FACTORY);
@@ -581,7 +587,8 @@
         int[] mergeFields = new int[] { 9, 0 };
         spec.connect(new MToNPartitioningMergingConnectorDescriptor(spec, new FieldHashPartitionComputerFactory(
                 new int[] { 9 }, new IBinaryHashFunctionFactory[] { new PointableBinaryHashFunctionFactory(
-                        UTF8StringPointable.FACTORY) }), mergeFields, comparatorFactories), join, 0, writer, 0);
+                        UTF8StringPointable.FACTORY) }), mergeFields, comparatorFactories, nmkFactory), join, 0,
+                writer, 0);
 
         spec.addRoot(writer);
         runTest(spec);
diff --git a/pregelix/pregelix-dataflow-std-base/pom.xml b/pregelix/pregelix-dataflow-std-base/pom.xml
index d4c0ee6..77d75bf 100644
--- a/pregelix/pregelix-dataflow-std-base/pom.xml
+++ b/pregelix/pregelix-dataflow-std-base/pom.xml
@@ -1,28 +1,24 @@
-<!--
- ! Copyright 2009-2013 by The Regents of the University of California
- ! Licensed under the Apache License, Version 2.0 (the "License");
- ! you may not use this file except in compliance with the License.
- ! you may obtain a copy of the License from
- ! 
- !     http://www.apache.org/licenses/LICENSE-2.0
- ! 
- ! Unless required by applicable law or agreed to in writing, software
- ! distributed under the License is distributed on an "AS IS" BASIS,
- ! WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- ! See the License for the specific language governing permissions and
- ! limitations under the License.
- !-->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<!-- ! Copyright 2009-2013 by The Regents of the University of California 
+	! Licensed under the Apache License, Version 2.0 (the "License"); ! you may 
+	not use this file except in compliance with the License. ! you may obtain 
+	a copy of the License from ! ! http://www.apache.org/licenses/LICENSE-2.0 
+	! ! Unless required by applicable law or agreed to in writing, software ! 
+	distributed under the License is distributed on an "AS IS" BASIS, ! WITHOUT 
+	WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. ! See the 
+	License for the specific language governing permissions and ! limitations 
+	under the License. ! -->
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 	<modelVersion>4.0.0</modelVersion>
 	<artifactId>pregelix-dataflow-std-base</artifactId>
 	<packaging>jar</packaging>
 	<name>pregelix-dataflow-std-base</name>
 
 	<parent>
-    		<groupId>edu.uci.ics.hyracks</groupId>
-    		<artifactId>pregelix</artifactId>
-    		<version>0.2.10-SNAPSHOT</version>
-  	</parent>
+		<groupId>edu.uci.ics.hyracks</groupId>
+		<artifactId>pregelix</artifactId>
+		<version>0.2.10-SNAPSHOT</version>
+	</parent>
 
 
 	<properties>
@@ -58,7 +54,7 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-clean-plugin</artifactId>
-                <version>2.4.1</version>
+				<version>2.4.1</version>
 				<configuration>
 					<filesets>
 						<fileset>
@@ -94,6 +90,20 @@
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
+			<artifactId>hyracks-hdfs-core</artifactId>
+			<version>0.2.10-SNAPSHOT</version>
+			<type>jar</type>
+			<scope>compile</scope>
+		</dependency>
+		<dependency>
+			<groupId>edu.uci.ics.hyracks</groupId>
+			<artifactId>hyracks-storage-am-common</artifactId>
+			<version>0.2.10-SNAPSHOT</version>
+			<type>jar</type>
+			<scope>compile</scope>
+		</dependency>
+		<dependency>
+			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-api</artifactId>
 			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
diff --git a/pregelix/pregelix-dataflow-std-base/src/main/java/edu/uci/ics/pregelix/dataflow/std/base/ISerializerDeserializerFactory.java b/pregelix/pregelix-dataflow-std-base/src/main/java/edu/uci/ics/pregelix/dataflow/std/base/ISerializerDeserializerFactory.java
index 1fdd0b6..894cba5 100644
--- a/pregelix/pregelix-dataflow-std-base/src/main/java/edu/uci/ics/pregelix/dataflow/std/base/ISerializerDeserializerFactory.java
+++ b/pregelix/pregelix-dataflow-std-base/src/main/java/edu/uci/ics/pregelix/dataflow/std/base/ISerializerDeserializerFactory.java
@@ -16,10 +16,12 @@
 
 import java.io.Serializable;
 
+import org.apache.hadoop.conf.Configuration;
+
 import edu.uci.ics.hyracks.api.dataflow.value.ISerializerDeserializer;
 
 public interface ISerializerDeserializerFactory<T> extends Serializable {
 
-	public ISerializerDeserializer<T> getSerializerDeserializer();
+    public ISerializerDeserializer<T> getSerializerDeserializer(Configuration conf);
 
 }
diff --git a/pregelix/pregelix-dataflow-std-base/src/main/java/edu/uci/ics/pregelix/dataflow/std/base/IUpdateFunction.java b/pregelix/pregelix-dataflow-std-base/src/main/java/edu/uci/ics/pregelix/dataflow/std/base/IUpdateFunction.java
index b8ba7bd..081b3bc 100644
--- a/pregelix/pregelix-dataflow-std-base/src/main/java/edu/uci/ics/pregelix/dataflow/std/base/IUpdateFunction.java
+++ b/pregelix/pregelix-dataflow-std-base/src/main/java/edu/uci/ics/pregelix/dataflow/std/base/IUpdateFunction.java
@@ -18,17 +18,18 @@
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
+import edu.uci.ics.hyracks.storage.am.common.api.IIndexCursor;
 
 public interface IUpdateFunction extends IFunction {
 
-	/**
-	 * update the tuple pointed by tupleRef called after process,
-	 * one-input-tuple-at-a-time
-	 * 
-	 * @param tupleRef
-	 * @throws HyracksDataException
-	 */
-	public void update(ITupleReference tupleRef, ArrayTupleBuilder cloneUpdateTb)
-			throws HyracksDataException;
+    /**
+     * update the tuple pointed by tupleRef called after process,
+     * one-input-tuple-at-a-time
+     * 
+     * @param tupleRef
+     * @throws HyracksDataException
+     */
+    public void update(ITupleReference tupleRef, ArrayTupleBuilder cloneUpdateTb, IIndexCursor cursor)
+            throws HyracksDataException;
 
 }
diff --git a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopJoinFunctionUpdateOperatorNodePushable.java b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopJoinFunctionUpdateOperatorNodePushable.java
index b22e468..c9bda52 100644
--- a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopJoinFunctionUpdateOperatorNodePushable.java
+++ b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopJoinFunctionUpdateOperatorNodePushable.java
@@ -34,6 +34,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.dataflow.AbstractTreeIndexOperatorDescriptor;
 import edu.uci.ics.hyracks.storage.am.common.dataflow.IndexDataflowHelper;
+import edu.uci.ics.hyracks.storage.am.common.dataflow.TreeIndexDataflowHelper;
 import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
 import edu.uci.ics.hyracks.storage.am.common.tuples.PermutingFrameTupleReference;
@@ -43,6 +44,7 @@
 import edu.uci.ics.pregelix.dataflow.util.CopyUpdateUtil;
 import edu.uci.ics.pregelix.dataflow.util.FunctionProxy;
 import edu.uci.ics.pregelix.dataflow.util.SearchKeyTupleReference;
+import edu.uci.ics.pregelix.dataflow.util.StorageType;
 import edu.uci.ics.pregelix.dataflow.util.UpdateBuffer;
 
 public class IndexNestedLoopJoinFunctionUpdateOperatorNodePushable extends AbstractUnaryInputOperatorNodePushable {
@@ -68,6 +70,7 @@
     private ArrayTupleBuilder cloneUpdateTb;
     private final UpdateBuffer updateBuffer;
     private final SearchKeyTupleReference tempTupleReference = new SearchKeyTupleReference();
+    private final StorageType storageType;
 
     public IndexNestedLoopJoinFunctionUpdateOperatorNodePushable(AbstractTreeIndexOperatorDescriptor opDesc,
             IHyracksTaskContext ctx, int partition, IRecordDescriptorProvider recordDescProvider, boolean isForward,
@@ -77,6 +80,11 @@
             throws HyracksDataException {
         treeIndexOpHelper = (IndexDataflowHelper) opDesc.getIndexDataflowHelperFactory().createIndexDataflowHelper(
                 opDesc, ctx, partition);
+        if (treeIndexOpHelper instanceof TreeIndexDataflowHelper) {
+            storageType = StorageType.TreeIndex;
+        } else {
+            storageType = StorageType.LSMIndex;
+        }
         this.lowKeyInclusive = lowKeyInclusive;
         this.highKeyInclusive = highKeyInclusive;
         this.recDesc = recordDescProvider.getInputRecordDescriptor(opDesc.getActivityId(), 0);
@@ -96,7 +104,7 @@
     }
 
     protected void setCursor() {
-        cursor = indexAccessor.createSearchCursor();
+        cursor = indexAccessor.createSearchCursor(true);
     }
 
     @Override
@@ -170,13 +178,13 @@
             /**
              * call the update function
              */
-            functionProxy.functionCall(leftAccessor, tIndex, indexEntryTuple, cloneUpdateTb);
+            functionProxy.functionCall(leftAccessor, tIndex, indexEntryTuple, cloneUpdateTb, cursor);
 
             /**
              * doing copy update
              */
             CopyUpdateUtil.copyUpdate(tempTupleReference, indexEntryTuple, updateBuffer, cloneUpdateTb, indexAccessor,
-                    cursor, rangePred);
+                    cursor, rangePred, false, storageType);
         }
     }
 
diff --git a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopJoinOperatorNodePushable.java b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopJoinOperatorNodePushable.java
index 2ddca90..b5b21b6 100644
--- a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopJoinOperatorNodePushable.java
+++ b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopJoinOperatorNodePushable.java
@@ -82,7 +82,7 @@
     }
 
     protected void setCursor() {
-        cursor = indexAccessor.createSearchCursor();
+        cursor = indexAccessor.createSearchCursor(false);
     }
 
     @Override
diff --git a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopRightOuterJoinFunctionUpdateOperatorNodePushable.java b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopRightOuterJoinFunctionUpdateOperatorNodePushable.java
index 0ecfd03..d77107e 100644
--- a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopRightOuterJoinFunctionUpdateOperatorNodePushable.java
+++ b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopRightOuterJoinFunctionUpdateOperatorNodePushable.java
@@ -36,6 +36,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.dataflow.AbstractTreeIndexOperatorDescriptor;
 import edu.uci.ics.hyracks.storage.am.common.dataflow.IndexDataflowHelper;
+import edu.uci.ics.hyracks.storage.am.common.dataflow.TreeIndexDataflowHelper;
 import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
 import edu.uci.ics.hyracks.storage.am.common.tuples.PermutingFrameTupleReference;
@@ -45,6 +46,7 @@
 import edu.uci.ics.pregelix.dataflow.util.CopyUpdateUtil;
 import edu.uci.ics.pregelix.dataflow.util.FunctionProxy;
 import edu.uci.ics.pregelix.dataflow.util.SearchKeyTupleReference;
+import edu.uci.ics.pregelix.dataflow.util.StorageType;
 import edu.uci.ics.pregelix.dataflow.util.UpdateBuffer;
 
 public class IndexNestedLoopRightOuterJoinFunctionUpdateOperatorNodePushable extends
@@ -79,6 +81,7 @@
     private ArrayTupleBuilder cloneUpdateTb;
     private final UpdateBuffer updateBuffer;
     private final SearchKeyTupleReference tempTupleReference = new SearchKeyTupleReference();
+    private final StorageType storageType;
 
     public IndexNestedLoopRightOuterJoinFunctionUpdateOperatorNodePushable(AbstractTreeIndexOperatorDescriptor opDesc,
             IHyracksTaskContext ctx, int partition, IRecordDescriptorProvider recordDescProvider, boolean isForward,
@@ -88,6 +91,11 @@
         inputRecDesc = recordDescProvider.getInputRecordDescriptor(opDesc.getActivityId(), 0);
         treeIndexOpHelper = (IndexDataflowHelper) opDesc.getIndexDataflowHelperFactory().createIndexDataflowHelper(
                 opDesc, ctx, partition);
+        if (treeIndexOpHelper instanceof TreeIndexDataflowHelper) {
+            storageType = StorageType.TreeIndex;
+        } else {
+            storageType = StorageType.LSMIndex;
+        }
         this.recDesc = recordDescProvider.getInputRecordDescriptor(opDesc.getActivityId(), 0);
 
         if (lowKeyFields != null && lowKeyFields.length > 0) {
@@ -107,7 +115,7 @@
     }
 
     protected void setCursor() {
-        cursor = indexAccessor.createSearchCursor();
+        cursor = indexAccessor.createSearchCursor(true);
     }
 
     @Override
@@ -287,13 +295,13 @@
         /**
          * function call
          */
-        functionProxy.functionCall(leftAccessor, tIndex, indexEntryTuple, cloneUpdateTb);
+        functionProxy.functionCall(leftAccessor, tIndex, indexEntryTuple, cloneUpdateTb, cursor);
 
         /**
          * doing clone update
          */
         CopyUpdateUtil.copyUpdate(tempTupleReference, indexEntryTuple, updateBuffer, cloneUpdateTb, indexAccessor,
-                cursor, rangePred);
+                cursor, rangePred, true, storageType);
     }
 
     /** write result for outer case */
@@ -301,11 +309,11 @@
         /**
          * function call
          */
-        functionProxy.functionCall(nullTupleBuilder, frameTuple, cloneUpdateTb);
+        functionProxy.functionCall(nullTupleBuilder, frameTuple, cloneUpdateTb, cursor);
 
         //doing clone update
         CopyUpdateUtil.copyUpdate(tempTupleReference, frameTuple, updateBuffer, cloneUpdateTb, indexAccessor, cursor,
-                rangePred);
+                rangePred, true, storageType);
     }
 
     @Override
diff --git a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopRightOuterJoinOperatorNodePushable.java b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopRightOuterJoinOperatorNodePushable.java
index e64e9cc..6539828 100644
--- a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopRightOuterJoinOperatorNodePushable.java
+++ b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopRightOuterJoinOperatorNodePushable.java
@@ -89,7 +89,7 @@
     }
 
     protected void setCursor() {
-        cursor = indexAccessor.createSearchCursor();
+        cursor = indexAccessor.createSearchCursor(false);
     }
 
     @Override
diff --git a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopSetUnionFunctionUpdateOperatorNodePushable.java b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopSetUnionFunctionUpdateOperatorNodePushable.java
index a9c787f..6549782 100644
--- a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopSetUnionFunctionUpdateOperatorNodePushable.java
+++ b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopSetUnionFunctionUpdateOperatorNodePushable.java
@@ -34,6 +34,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.dataflow.AbstractTreeIndexOperatorDescriptor;
 import edu.uci.ics.hyracks.storage.am.common.dataflow.IndexDataflowHelper;
+import edu.uci.ics.hyracks.storage.am.common.dataflow.TreeIndexDataflowHelper;
 import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
 import edu.uci.ics.hyracks.storage.am.common.tuples.PermutingFrameTupleReference;
@@ -43,6 +44,7 @@
 import edu.uci.ics.pregelix.dataflow.util.CopyUpdateUtil;
 import edu.uci.ics.pregelix.dataflow.util.FunctionProxy;
 import edu.uci.ics.pregelix.dataflow.util.SearchKeyTupleReference;
+import edu.uci.ics.pregelix.dataflow.util.StorageType;
 import edu.uci.ics.pregelix.dataflow.util.UpdateBuffer;
 
 public class IndexNestedLoopSetUnionFunctionUpdateOperatorNodePushable extends AbstractUnaryInputOperatorNodePushable {
@@ -71,6 +73,7 @@
     private ArrayTupleBuilder cloneUpdateTb;
     private UpdateBuffer updateBuffer;
     private final SearchKeyTupleReference tempTupleReference = new SearchKeyTupleReference();
+    private final StorageType storageType;
 
     public IndexNestedLoopSetUnionFunctionUpdateOperatorNodePushable(AbstractTreeIndexOperatorDescriptor opDesc,
             IHyracksTaskContext ctx, int partition, IRecordDescriptorProvider recordDescProvider, boolean isForward,
@@ -79,6 +82,11 @@
             IRecordDescriptorFactory inputRdFactory, int outputArity) throws HyracksDataException {
         treeIndexOpHelper = (IndexDataflowHelper) opDesc.getIndexDataflowHelperFactory().createIndexDataflowHelper(
                 opDesc, ctx, partition);
+        if (treeIndexOpHelper instanceof TreeIndexDataflowHelper) {
+            storageType = StorageType.TreeIndex;
+        } else {
+            storageType = StorageType.LSMIndex;
+        }
         this.isForward = isForward;
         this.recDesc = recordDescProvider.getInputRecordDescriptor(opDesc.getActivityId(), 0);
 
@@ -98,7 +106,7 @@
     }
 
     protected void setCursor() {
-        cursor = indexAccessor.createSearchCursor();
+        cursor = indexAccessor.createSearchCursor(true);
     }
 
     @Override
@@ -238,21 +246,21 @@
 
     /** write the right result */
     private void writeRightResults(ITupleReference frameTuple) throws Exception {
-        functionProxy.functionCall(frameTuple, cloneUpdateTb);
+        functionProxy.functionCall(frameTuple, cloneUpdateTb, cursor);
 
         //doing clone update
         CopyUpdateUtil.copyUpdate(tempTupleReference, frameTuple, updateBuffer, cloneUpdateTb, indexAccessor, cursor,
-                rangePred);
+                rangePred, true, storageType);
     }
 
     /** write the left result */
     private void writeLeftResults(IFrameTupleAccessor leftAccessor, int tIndex, ITupleReference frameTuple)
             throws Exception {
-        functionProxy.functionCall(leftAccessor, tIndex, frameTuple, cloneUpdateTb);
+        functionProxy.functionCall(leftAccessor, tIndex, frameTuple, cloneUpdateTb, cursor);
 
         //doing clone update
         CopyUpdateUtil.copyUpdate(tempTupleReference, frameTuple, updateBuffer, cloneUpdateTb, indexAccessor, cursor,
-                rangePred);
+                rangePred, true, storageType);
     }
 
     @Override
diff --git a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopSetUnionOperatorNodePushable.java b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopSetUnionOperatorNodePushable.java
index 86a211f..1c9fce6 100644
--- a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopSetUnionOperatorNodePushable.java
+++ b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/IndexNestedLoopSetUnionOperatorNodePushable.java
@@ -82,7 +82,7 @@
     }
 
     protected void setCursor() {
-        cursor = indexAccessor.createSearchCursor();
+        cursor = indexAccessor.createSearchCursor(false);
     }
 
     @Override
diff --git a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/TreeSearchFunctionUpdateOperatorNodePushable.java b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/TreeSearchFunctionUpdateOperatorNodePushable.java
index de87909..0561f8b 100644
--- a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/TreeSearchFunctionUpdateOperatorNodePushable.java
+++ b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/std/TreeSearchFunctionUpdateOperatorNodePushable.java
@@ -35,6 +35,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexFrame;
 import edu.uci.ics.hyracks.storage.am.common.dataflow.AbstractTreeIndexOperatorDescriptor;
 import edu.uci.ics.hyracks.storage.am.common.dataflow.IndexDataflowHelper;
+import edu.uci.ics.hyracks.storage.am.common.dataflow.TreeIndexDataflowHelper;
 import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
 import edu.uci.ics.hyracks.storage.am.common.tuples.PermutingFrameTupleReference;
@@ -44,6 +45,7 @@
 import edu.uci.ics.pregelix.dataflow.util.CopyUpdateUtil;
 import edu.uci.ics.pregelix.dataflow.util.FunctionProxy;
 import edu.uci.ics.pregelix.dataflow.util.SearchKeyTupleReference;
+import edu.uci.ics.pregelix.dataflow.util.StorageType;
 import edu.uci.ics.pregelix.dataflow.util.UpdateBuffer;
 
 public class TreeSearchFunctionUpdateOperatorNodePushable extends AbstractUnaryInputOperatorNodePushable {
@@ -77,6 +79,7 @@
     private ArrayTupleBuilder cloneUpdateTb;
     private final UpdateBuffer updateBuffer;
     private final SearchKeyTupleReference tempTupleReference = new SearchKeyTupleReference();
+    private final StorageType storageType;
 
     public TreeSearchFunctionUpdateOperatorNodePushable(AbstractTreeIndexOperatorDescriptor opDesc,
             IHyracksTaskContext ctx, int partition, IRecordDescriptorProvider recordDescProvider, boolean isForward,
@@ -86,6 +89,11 @@
             throws HyracksDataException {
         treeIndexHelper = (IndexDataflowHelper) opDesc.getIndexDataflowHelperFactory().createIndexDataflowHelper(
                 opDesc, ctx, partition);
+        if (treeIndexHelper instanceof TreeIndexDataflowHelper) {
+            storageType = StorageType.TreeIndex;
+        } else {
+            storageType = StorageType.LSMIndex;
+        }
         this.isForward = isForward;
         this.lowKeyInclusive = lowKeyInclusive;
         this.highKeyInclusive = highKeyInclusive;
@@ -164,18 +172,18 @@
     }
 
     protected void setCursor() {
-        cursor = indexAccessor.createSearchCursor();
+        cursor = indexAccessor.createSearchCursor(true);
     }
 
     protected void writeSearchResults() throws Exception {
         while (cursor.hasNext()) {
             cursor.next();
             ITupleReference tuple = cursor.getTuple();
-            functionProxy.functionCall(tuple, cloneUpdateTb);
+            functionProxy.functionCall(tuple, cloneUpdateTb, cursor);
 
             //doing clone update
             CopyUpdateUtil.copyUpdate(tempTupleReference, tuple, updateBuffer, cloneUpdateTb, indexAccessor, cursor,
-                    rangePred);
+                    rangePred, true, storageType);
         }
     }
 
diff --git a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/CopyUpdateUtil.java b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/CopyUpdateUtil.java
index 392f728..0ff3f04 100644
--- a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/CopyUpdateUtil.java
+++ b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/CopyUpdateUtil.java
@@ -27,19 +27,9 @@
 
     public static void copyUpdate(SearchKeyTupleReference tempTupleReference, ITupleReference frameTuple,
             UpdateBuffer updateBuffer, ArrayTupleBuilder cloneUpdateTb, IIndexAccessor indexAccessor,
-            IIndexCursor cursor, RangePredicate rangePred) throws HyracksDataException, IndexException {
+            IIndexCursor cursor, RangePredicate rangePred, boolean scan, StorageType type) throws HyracksDataException,
+            IndexException {
         if (cloneUpdateTb.getSize() > 0) {
-            int[] fieldEndOffsets = cloneUpdateTb.getFieldEndOffsets();
-            int srcStart = fieldEndOffsets[0];
-            int srcLen = fieldEndOffsets[1] - fieldEndOffsets[0]; // the updated vertex size
-            int frSize = frameTuple.getFieldLength(1); // the vertex binary size in the leaf page
-            if (srcLen <= frSize) {
-                //doing in-place update if the vertex size is not larger than the original size, save the "real update" overhead
-                System.arraycopy(cloneUpdateTb.getByteArray(), srcStart, frameTuple.getFieldData(1),
-                        frameTuple.getFieldStart(1), srcLen);
-                cloneUpdateTb.reset();
-                return;
-            }
             if (!updateBuffer.appendTuple(cloneUpdateTb)) {
                 tempTupleReference.reset(frameTuple.getFieldData(0), frameTuple.getFieldStart(0),
                         frameTuple.getFieldLength(0));
@@ -51,11 +41,18 @@
                 if (!updateBuffer.appendTuple(cloneUpdateTb)) {
                     throw new HyracksDataException("cannot append tuple builder!");
                 }
-                //search again and recover the cursor
+                //search again and recover the cursor to the exact point as the one before it is closed
                 cursor.reset();
-                rangePred.setLowKey(tempTupleReference, false);
-                rangePred.setHighKey(null, true);
+                rangePred.setLowKey(tempTupleReference, true);
+                if (scan) {
+                    rangePred.setHighKey(null, true);
+                } else {
+                    rangePred.setHighKey(tempTupleReference, true);
+                }
                 indexAccessor.search(cursor, rangePred);
+                if (cursor.hasNext()) {
+                    cursor.next();
+                }
             }
             cloneUpdateTb.reset();
         }
diff --git a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/FunctionProxy.java b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/FunctionProxy.java
index a1e5b86..5579a77 100644
--- a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/FunctionProxy.java
+++ b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/FunctionProxy.java
@@ -22,6 +22,7 @@
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
+import edu.uci.ics.hyracks.storage.am.common.api.IIndexCursor;
 import edu.uci.ics.pregelix.dataflow.std.base.IRecordDescriptorFactory;
 import edu.uci.ics.pregelix.dataflow.std.base.IRuntimeHookFactory;
 import edu.uci.ics.pregelix.dataflow.std.base.IUpdateFunction;
@@ -56,10 +57,10 @@
      * @throws HyracksDataException
      */
     public void functionOpen() throws HyracksDataException {
+        ctxCL = Thread.currentThread().getContextClassLoader();
+        Thread.currentThread().setContextClassLoader(ctx.getJobletContext().getClassLoader());
         inputRd = inputRdFactory.createRecordDescriptor(ctx);
         tupleDe = new TupleDeserializer(inputRd);
-        ctxCL = Thread.currentThread().getContextClassLoader();
-        Thread.currentThread().setContextClassLoader(this.getClass().getClassLoader());
         for (IFrameWriter writer : writers) {
             writer.open();
         }
@@ -80,10 +81,10 @@
      * @throws HyracksDataException
      */
     public void functionCall(IFrameTupleAccessor leftAccessor, int leftTupleIndex, ITupleReference right,
-            ArrayTupleBuilder cloneUpdateTb) throws HyracksDataException {
+            ArrayTupleBuilder cloneUpdateTb, IIndexCursor cursor) throws HyracksDataException {
         Object[] tuple = tupleDe.deserializeRecord(leftAccessor, leftTupleIndex, right);
         function.process(tuple);
-        function.update(right, cloneUpdateTb);
+        function.update(right, cloneUpdateTb, cursor);
     }
 
     /**
@@ -92,10 +93,11 @@
      * @param updateRef
      * @throws HyracksDataException
      */
-    public void functionCall(ITupleReference updateRef, ArrayTupleBuilder cloneUpdateTb) throws HyracksDataException {
+    public void functionCall(ITupleReference updateRef, ArrayTupleBuilder cloneUpdateTb, IIndexCursor cursor)
+            throws HyracksDataException {
         Object[] tuple = tupleDe.deserializeRecord(updateRef);
         function.process(tuple);
-        function.update(updateRef, cloneUpdateTb);
+        function.update(updateRef, cloneUpdateTb, cursor);
     }
 
     /**
@@ -107,11 +109,11 @@
      *            update pointer
      * @throws HyracksDataException
      */
-    public void functionCall(ArrayTupleBuilder tb, ITupleReference inPlaceUpdateRef, ArrayTupleBuilder cloneUpdateTb)
-            throws HyracksDataException {
+    public void functionCall(ArrayTupleBuilder tb, ITupleReference inPlaceUpdateRef, ArrayTupleBuilder cloneUpdateTb,
+            IIndexCursor cursor) throws HyracksDataException {
         Object[] tuple = tupleDe.deserializeRecord(tb, inPlaceUpdateRef);
         function.process(tuple);
-        function.update(inPlaceUpdateRef, cloneUpdateTb);
+        function.update(inPlaceUpdateRef, cloneUpdateTb, cursor);
     }
 
     /**
diff --git a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/StorageType.java b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/StorageType.java
new file mode 100644
index 0000000..fb2d1eb
--- /dev/null
+++ b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/StorageType.java
@@ -0,0 +1,21 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.pregelix.dataflow.util;
+
+public enum StorageType {
+    TreeIndex,
+    LSMIndex
+}
diff --git a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/MaterializingReadOperatorDescriptor.java b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/MaterializingReadOperatorDescriptor.java
index b44b643..a5d2ab7 100644
--- a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/MaterializingReadOperatorDescriptor.java
+++ b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/MaterializingReadOperatorDescriptor.java
@@ -31,11 +31,15 @@
 public class MaterializingReadOperatorDescriptor extends AbstractSingleActivityOperatorDescriptor {
     private static final long serialVersionUID = 1L;
     private final boolean removeIterationState;
+    private final String jobId;
+    private final int iteration;
 
     public MaterializingReadOperatorDescriptor(JobSpecification spec, RecordDescriptor recordDescriptor,
-            boolean removeIterationState) {
+            boolean removeIterationState, String jobId, int iteration) {
         super(spec, 1, 1);
         this.removeIterationState = removeIterationState;
+        this.jobId = jobId;
+        this.iteration = iteration - 1;
         recordDescriptors[0] = recordDescriptor;
     }
 
@@ -55,8 +59,8 @@
             @Override
             public void nextFrame(ByteBuffer buffer) throws HyracksDataException {
                 if (!complete) {
-                    MaterializerTaskState state = (MaterializerTaskState) IterationUtils.getIterationState(ctx,
-                            partition);
+                    MaterializerTaskState state = (MaterializerTaskState) IterationUtils.getIterationState(ctx, jobId,
+                            partition, iteration);
                     RunFileReader in = state.getRunFileWriter().createReader();
                     writer.open();
                     try {
@@ -85,7 +89,7 @@
                  * remove last iteration's state
                  */
                 if (removeIterationState) {
-                    IterationUtils.removeIterationState(ctx, partition);
+                    IterationUtils.removeIterationState(ctx, jobId, partition, iteration);
                 }
                 writer.close();
                 complete = true;
diff --git a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/MaterializingWriteOperatorDescriptor.java b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/MaterializingWriteOperatorDescriptor.java
index 00dcbd1..921dc40 100644
--- a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/MaterializingWriteOperatorDescriptor.java
+++ b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/MaterializingWriteOperatorDescriptor.java
@@ -38,9 +38,14 @@
 public class MaterializingWriteOperatorDescriptor extends AbstractOperatorDescriptor {
     private static final long serialVersionUID = 1L;
     private final static int MATERIALIZER_ACTIVITY_ID = 0;
+    private final String jobId;
+    private final int iteration;
 
-    public MaterializingWriteOperatorDescriptor(JobSpecification spec, RecordDescriptor recordDescriptor) {
+    public MaterializingWriteOperatorDescriptor(JobSpecification spec, RecordDescriptor recordDescriptor, String jobId,
+            int iteration) {
         super(spec, 1, 1);
+        this.jobId = jobId;
+        this.iteration = iteration;
         recordDescriptors[0] = recordDescriptor;
     }
 
@@ -69,13 +74,12 @@
                 @Override
                 public void open() throws HyracksDataException {
                     /** remove last iteration's state */
-                    IterationUtils.removeIterationState(ctx, partition);
+                    IterationUtils.removeIterationState(ctx, jobId, partition, iteration);
                     state = new MaterializerTaskState(ctx.getJobletContext().getJobId(), new TaskId(getActivityId(),
                             partition));
                     INCApplicationContext appContext = ctx.getJobletContext().getApplicationContext();
                     RuntimeContext context = (RuntimeContext) appContext.getApplicationObject();
-                    FileReference file = context.createManagedWorkspaceFile(MaterializingWriteOperatorDescriptor.class
-                            .getSimpleName());
+                    FileReference file = context.createManagedWorkspaceFile(jobId);
                     state.setRunFileWriter(new RunFileWriter(file, ctx.getIOManager()));
                     state.getRunFileWriter().open();
                     writer.open();
@@ -92,7 +96,7 @@
                     /**
                      * set iteration state
                      */
-                    IterationUtils.setIterationState(ctx, partition, state);
+                    IterationUtils.setIterationState(ctx, jobId, partition, iteration, state);
                     writer.close();
                 }
 
diff --git a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/VertexFileScanOperatorDescriptor.java b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/VertexFileScanOperatorDescriptor.java
index b34879e..e16ba48 100644
--- a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/VertexFileScanOperatorDescriptor.java
+++ b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/VertexFileScanOperatorDescriptor.java
@@ -16,6 +16,8 @@
 
 import java.io.DataOutput;
 import java.io.IOException;
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -122,7 +124,7 @@
             @SuppressWarnings("unchecked")
             private void loadVertices(final IHyracksTaskContext ctx, Configuration conf, int splitId)
                     throws IOException, ClassNotFoundException, InterruptedException, InstantiationException,
-                    IllegalAccessException {
+                    IllegalAccessException, NoSuchFieldException, InvocationTargetException {
                 ByteBuffer frame = ctx.allocateFrame();
                 FrameTupleAppender appender = new FrameTupleAppender(ctx.getFrameSize());
                 appender.reset(frame, true);
@@ -141,7 +143,11 @@
                 /**
                  * set context
                  */
-                Vertex.setContext(mapperContext);
+                ClassLoader cl = ctx.getJobletContext().getClassLoader();
+                Class<?> vClass = (Class<?>) cl.loadClass("edu.uci.ics.pregelix.api.graph.Vertex");
+                Field contextField = vClass.getDeclaredField("context");
+                contextField.setAccessible(true);
+                contextField.set(null, mapperContext);
 
                 /**
                  * empty vertex value
diff --git a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/VertexFileWriteOperatorDescriptor.java b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/VertexFileWriteOperatorDescriptor.java
index f3ec40e..2087ea2 100644
--- a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/VertexFileWriteOperatorDescriptor.java
+++ b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/VertexFileWriteOperatorDescriptor.java
@@ -44,17 +44,20 @@
 import edu.uci.ics.pregelix.api.util.BspUtils;
 import edu.uci.ics.pregelix.dataflow.base.IConfigurationFactory;
 import edu.uci.ics.pregelix.dataflow.std.base.IRecordDescriptorFactory;
+import edu.uci.ics.pregelix.dataflow.std.base.IRuntimeHookFactory;
 
 public class VertexFileWriteOperatorDescriptor extends AbstractSingleActivityOperatorDescriptor {
     private static final long serialVersionUID = 1L;
     private final IConfigurationFactory confFactory;
     private final IRecordDescriptorFactory inputRdFactory;
+    private final IRuntimeHookFactory preHookFactory;
 
     public VertexFileWriteOperatorDescriptor(JobSpecification spec, IConfigurationFactory confFactory,
-            IRecordDescriptorFactory inputRdFactory) {
+            IRecordDescriptorFactory inputRdFactory, IRuntimeHookFactory preHookFactory) {
         super(spec, 1, 0);
         this.confFactory = confFactory;
         this.inputRdFactory = inputRdFactory;
+        this.preHookFactory = preHookFactory;
     }
 
     @SuppressWarnings("rawtypes")
@@ -85,6 +88,8 @@
                 context = ctxFactory.createContext(conf, partition);
                 context.getConfiguration().setClassLoader(ctx.getJobletContext().getClassLoader());
                 try {
+                    if (preHookFactory != null)
+                        preHookFactory.createRuntimeHook().configure(ctx);
                     vertexWriter = outputFormat.createVertexWriter(context);
                 } catch (InterruptedException e) {
                     throw new HyracksDataException(e);
diff --git a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/context/PJobContext.java b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/context/PJobContext.java
new file mode 100644
index 0000000..ceb085c
--- /dev/null
+++ b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/context/PJobContext.java
@@ -0,0 +1,126 @@
+package edu.uci.ics.pregelix.dataflow.context;
+
+import java.lang.reflect.Method;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.logging.Logger;
+
+import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
+import edu.uci.ics.hyracks.api.dataflow.state.IStateObject;
+import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+import edu.uci.ics.hyracks.api.io.FileReference;
+import edu.uci.ics.pregelix.api.graph.Vertex;
+
+public class PJobContext {
+    private static final Logger LOGGER = Logger.getLogger(RuntimeContext.class.getName());
+
+    private final Map<Long, List<FileReference>> iterationToFiles = new ConcurrentHashMap<Long, List<FileReference>>();
+    private final Map<TaskIterationID, IStateObject> appStateMap = new ConcurrentHashMap<TaskIterationID, IStateObject>();
+    private Long jobIdToSuperStep;
+    private Boolean jobIdToMove;
+
+    public void close() throws HyracksDataException {
+        for (Entry<Long, List<FileReference>> entry : iterationToFiles.entrySet())
+            for (FileReference fileRef : entry.getValue())
+                fileRef.delete();
+
+        iterationToFiles.clear();
+        appStateMap.clear();
+    }
+
+    public void clearState() throws HyracksDataException {
+        for (Entry<Long, List<FileReference>> entry : iterationToFiles.entrySet())
+            for (FileReference fileRef : entry.getValue())
+                fileRef.delete();
+
+        iterationToFiles.clear();
+        appStateMap.clear();
+    }
+
+    public Map<TaskIterationID, IStateObject> getAppStateStore() {
+        return appStateMap;
+    }
+
+    public static RuntimeContext get(IHyracksTaskContext ctx) {
+        return (RuntimeContext) ctx.getJobletContext().getApplicationContext().getApplicationObject();
+    }
+
+    public void setVertexProperties(long numVertices, long numEdges, long currentIteration, ClassLoader cl) {
+        if (jobIdToMove == null || jobIdToMove == true) {
+            if (jobIdToSuperStep == null) {
+                if (currentIteration <= 0) {
+                    jobIdToSuperStep = 0L;
+                } else {
+                    jobIdToSuperStep = currentIteration;
+                }
+            }
+
+            long superStep = jobIdToSuperStep;
+            List<FileReference> files = iterationToFiles.remove(superStep - 1);
+            if (files != null) {
+                for (FileReference fileRef : files)
+                    fileRef.delete();
+            }
+
+            setProperties(numVertices, numEdges, currentIteration, superStep, false, cl);
+        }
+        System.gc();
+    }
+
+    public void recoverVertexProperties(long numVertices, long numEdges, long currentIteration, ClassLoader cl) {
+        if (jobIdToSuperStep == null) {
+            if (currentIteration <= 0) {
+                jobIdToSuperStep = 0L;
+            } else {
+                jobIdToSuperStep = currentIteration;
+            }
+        }
+
+        long superStep = jobIdToSuperStep;
+        List<FileReference> files = iterationToFiles.remove(superStep - 1);
+        if (files != null) {
+            for (FileReference fileRef : files)
+                fileRef.delete();
+        }
+
+        setProperties(numVertices, numEdges, currentIteration, superStep, true, cl);
+    }
+
+    public void endSuperStep() {
+        jobIdToMove = true;
+        LOGGER.info("end iteration " + Vertex.getSuperstep());
+    }
+
+    public Map<Long, List<FileReference>> getIterationToFiles() {
+        return iterationToFiles;
+    }
+
+    private void setProperties(long numVertices, long numEdges, long currentIteration, long superStep, boolean toMove,
+            ClassLoader cl) {
+        try {
+            Class<?> vClass = (Class<?>) cl.loadClass("edu.uci.ics.pregelix.api.graph.Vertex");
+            Method superStepMethod = vClass.getMethod("setSuperstep", Long.TYPE);
+            Method numVerticesMethod = vClass.getMethod("setNumVertices", Long.TYPE);
+            Method numEdgesMethod = vClass.getMethod("setNumEdges", Long.TYPE);
+
+            if (currentIteration > 0) {
+                //Vertex.setSuperstep(currentIteration);
+                superStepMethod.invoke(null, currentIteration);
+            } else {
+                //Vertex.setSuperstep(++superStep);
+                superStepMethod.invoke(null, ++superStep);
+            }
+            //Vertex.setNumVertices(numVertices);
+            numVerticesMethod.invoke(null, numVertices);
+            //Vertex.setNumEdges(numEdges);
+            numEdgesMethod.invoke(null, numEdges);
+            jobIdToSuperStep = superStep;
+            jobIdToMove = toMove;
+            LOGGER.info("start iteration " + Vertex.getSuperstep());
+        } catch (Exception e) {
+            throw new IllegalStateException(e);
+        }
+    }
+}
diff --git a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/context/RuntimeContext.java b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/context/RuntimeContext.java
index f3f7513..854e3dc 100644
--- a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/context/RuntimeContext.java
+++ b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/context/RuntimeContext.java
@@ -20,7 +20,6 @@
 import java.util.Map.Entry;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ThreadFactory;
-import java.util.logging.Logger;
 
 import edu.uci.ics.hyracks.api.application.INCApplicationContext;
 import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
@@ -48,7 +47,6 @@
 import edu.uci.ics.pregelix.api.graph.Vertex;
 
 public class RuntimeContext implements IWorkspaceFileFactory {
-    private static final Logger LOGGER = Logger.getLogger(RuntimeContext.class.getName());
 
     private final IIndexLifecycleManager lcManager;
     private final ILocalResourceRepository localResourceRepository;
@@ -57,10 +55,7 @@
     private final List<IVirtualBufferCache> vbcs;
     private final IFileMapManager fileMapManager;
     private final IOManager ioManager;
-    private final Map<Long, List<FileReference>> iterationToFiles = new ConcurrentHashMap<Long, List<FileReference>>();
-    private final Map<StateKey, IStateObject> appStateMap = new ConcurrentHashMap<StateKey, IStateObject>();
-    private final Map<String, Long> jobIdToSuperStep = new ConcurrentHashMap<String, Long>();
-    private final Map<String, Boolean> jobIdToMove = new ConcurrentHashMap<String, Boolean>();
+    private final Map<String, PJobContext> activeJobs = new ConcurrentHashMap<String, PJobContext>();
 
     private final ThreadFactory threadFactory = new ThreadFactory() {
         public Thread newThread(Runnable r) {
@@ -91,28 +86,12 @@
         resourceIdFactory = new ResourceIdFactory(0);
     }
 
-    public void close() throws HyracksDataException {
-        for (Entry<Long, List<FileReference>> entry : iterationToFiles.entrySet())
-            for (FileReference fileRef : entry.getValue())
-                fileRef.delete();
-
-        iterationToFiles.clear();
+    public synchronized void close() throws HyracksDataException {
         bufferCache.close();
-        appStateMap.clear();
-
-        System.gc();
-    }
-
-    public void clearState(String jobId) throws HyracksDataException {
-        for (Entry<Long, List<FileReference>> entry : iterationToFiles.entrySet())
-            for (FileReference fileRef : entry.getValue())
-                fileRef.delete();
-
-        iterationToFiles.clear();
-        appStateMap.clear();
-        jobIdToMove.remove(jobId);
-        jobIdToSuperStep.remove(jobId);
-        System.gc();
+        for (Entry<String, PJobContext> entry : activeJobs.entrySet()) {
+            entry.getValue().close();
+        }
+        activeJobs.clear();
     }
 
     public ILocalResourceRepository getLocalResourceRepository() {
@@ -139,87 +118,55 @@
         return fileMapManager;
     }
 
-    public Map<StateKey, IStateObject> getAppStateStore() {
-        return appStateMap;
+    public synchronized Map<TaskIterationID, IStateObject> getAppStateStore(String jobId) {
+        PJobContext activeJob = getActiveJob(jobId);
+        return activeJob.getAppStateStore();
     }
 
     public static RuntimeContext get(IHyracksTaskContext ctx) {
         return (RuntimeContext) ctx.getJobletContext().getApplicationContext().getApplicationObject();
     }
 
-    public synchronized void setVertexProperties(String jobId, long numVertices, long numEdges, long currentIteration) {
-        Boolean toMove = jobIdToMove.get(jobId);
-        if (toMove == null || toMove == true) {
-            if (jobIdToSuperStep.get(jobId) == null) {
-                if (currentIteration <= 0) {
-                    jobIdToSuperStep.put(jobId, 0L);
-                } else {
-                    jobIdToSuperStep.put(jobId, currentIteration);
-                }
-            }
-
-            long superStep = jobIdToSuperStep.get(jobId);
-            List<FileReference> files = iterationToFiles.remove(superStep - 1);
-            if (files != null) {
-                for (FileReference fileRef : files)
-                    fileRef.delete();
-            }
-
-            if (currentIteration > 0) {
-                Vertex.setSuperstep(currentIteration);
-            } else {
-                Vertex.setSuperstep(++superStep);
-            }
-            Vertex.setNumVertices(numVertices);
-            Vertex.setNumEdges(numEdges);
-            jobIdToSuperStep.put(jobId, superStep);
-            jobIdToMove.put(jobId, false);
-            LOGGER.info("start iteration " + Vertex.getSuperstep());
-        }
-        System.gc();
+    public synchronized void setVertexProperties(String jobId, long numVertices, long numEdges, long currentIteration,
+            ClassLoader cl) {
+        PJobContext activeJob = getActiveJob(jobId);
+        activeJob.setVertexProperties(numVertices, numEdges, currentIteration, cl);
     }
 
     public synchronized void recoverVertexProperties(String jobId, long numVertices, long numEdges,
-            long currentIteration) {
-        if (jobIdToSuperStep.get(jobId) == null) {
-            if (currentIteration <= 0) {
-                jobIdToSuperStep.put(jobId, 0L);
-            } else {
-                jobIdToSuperStep.put(jobId, currentIteration);
-            }
-        }
-
-        long superStep = jobIdToSuperStep.get(jobId);
-        List<FileReference> files = iterationToFiles.remove(superStep - 1);
-        if (files != null) {
-            for (FileReference fileRef : files)
-                fileRef.delete();
-        }
-
-        if (currentIteration > 0) {
-            Vertex.setSuperstep(currentIteration);
-        } else {
-            Vertex.setSuperstep(++superStep);
-        }
-        Vertex.setNumVertices(numVertices);
-        Vertex.setNumEdges(numEdges);
-        jobIdToSuperStep.put(jobId, superStep);
-        jobIdToMove.put(jobId, true);
-        LOGGER.info("recovered iteration " + Vertex.getSuperstep());
+            long currentIteration, ClassLoader cl) {
+        PJobContext activeJob = getActiveJob(jobId);
+        activeJob.recoverVertexProperties(numVertices, numEdges, currentIteration, cl);
     }
 
-    public synchronized void endSuperStep(String pregelixJobId) {
-        jobIdToMove.put(pregelixJobId, true);
-        LOGGER.info("end iteration " + Vertex.getSuperstep());
+    public synchronized void endSuperStep(String jobId) {
+        PJobContext activeJob = getActiveJob(jobId);
+        activeJob.endSuperStep();
+    }
+
+    public synchronized void clearState(String jobId) throws HyracksDataException {
+        PJobContext activeJob = getActiveJob(jobId);
+        activeJob.clearState();
+        activeJobs.remove(jobId);
+    }
+
+    private PJobContext getActiveJob(String jobId) {
+        PJobContext activeJob = activeJobs.get(jobId);
+        if (activeJob == null) {
+            activeJob = new PJobContext();
+            activeJobs.put(jobId, activeJob);
+        }
+        return activeJob;
     }
 
     @Override
-    public FileReference createManagedWorkspaceFile(String prefix) throws HyracksDataException {
-        final FileReference fRef = ioManager.createWorkspaceFile(prefix);
-        List<FileReference> files = iterationToFiles.get(Vertex.getSuperstep());
+    public FileReference createManagedWorkspaceFile(String jobId) throws HyracksDataException {
+        final FileReference fRef = ioManager.createWorkspaceFile(jobId);
+        PJobContext activeJob = getActiveJob(jobId);
+        List<FileReference> files = activeJob.getIterationToFiles().get(Vertex.getSuperstep());
         if (files == null) {
             files = new ArrayList<FileReference>();
-            iterationToFiles.put(Vertex.getSuperstep(), files);
+            activeJob.getIterationToFiles().put(Vertex.getSuperstep(), files);
         }
         files.add(fRef);
         return fRef;
@@ -229,4 +176,5 @@
     public FileReference createUnmanagedWorkspaceFile(String prefix) throws HyracksDataException {
         return ioManager.createWorkspaceFile(prefix);
     }
+
 }
\ No newline at end of file
diff --git a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/context/StateKey.java b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/context/TaskID.java
similarity index 64%
rename from pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/context/StateKey.java
rename to pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/context/TaskID.java
index cbd90b9..f219ed2 100644
--- a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/context/StateKey.java
+++ b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/context/TaskID.java
@@ -12,34 +12,44 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package edu.uci.ics.pregelix.dataflow.context;
 
-import edu.uci.ics.hyracks.api.job.JobId;
+public class TaskID {
 
-public class StateKey {
-    private final JobId jobId;
-    private final int partition;
+    private String jobId;
+    private int partition;
 
-    public StateKey(JobId jobId, int partition) {
+    public TaskID(String jobId, int partition) {
         this.jobId = jobId;
         this.partition = partition;
     }
 
+    public String getJobId() {
+        return jobId;
+    }
+
+    public int getPartition() {
+        return partition;
+    }
+
     @Override
     public int hashCode() {
-        return jobId.hashCode() * partition;
+        return jobId.hashCode() + partition;
     }
 
     @Override
     public boolean equals(Object o) {
-        if (!(o instanceof StateKey))
+        if (!(o instanceof TaskID)) {
             return false;
-        StateKey key = (StateKey) o;
-        return key.jobId.equals(jobId) && key.partition == partition;
+        }
+        TaskID tid = (TaskID) o;
+        return jobId.equals(tid.getJobId()) && partition == tid.getPartition();
     }
 
     @Override
     public String toString() {
-        return jobId.toString() + ":" + partition;
+        return "job:" + jobId + " partition:" + partition;
     }
+
 }
diff --git a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/context/TaskIterationID.java b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/context/TaskIterationID.java
new file mode 100644
index 0000000..53c6a0c
--- /dev/null
+++ b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/context/TaskIterationID.java
@@ -0,0 +1,51 @@
+package edu.uci.ics.pregelix.dataflow.context;
+
+public class TaskIterationID {
+
+    private TaskID tid;
+    private int iteration;
+
+    public TaskIterationID(TaskID tid, int iteration) {
+        this.tid = tid;
+        this.iteration = iteration;
+    }
+
+    public TaskIterationID(String jobId, int partition, int iteration) {
+        this.tid = new TaskID(jobId, partition);
+        this.iteration = iteration;
+    }
+
+    public TaskID getTaskID() {
+        return tid;
+    }
+
+    public int getIteration() {
+        return iteration;
+    }
+
+    public TaskIterationID getNextTaskIterationID() {
+        return new TaskIterationID(tid, iteration + 1);
+    }
+
+    public TaskIterationID getPreviousTaskIterationID() {
+        return new TaskIterationID(tid, iteration - 1);
+    }
+
+    @Override
+    public int hashCode() {
+        return tid.hashCode() + iteration;
+    }
+
+    public boolean equals(Object o) {
+        if (!(o instanceof TaskIterationID)) {
+            return false;
+        }
+        TaskIterationID tiid = (TaskIterationID) o;
+        return tid.equals(tiid.getTaskID()) && iteration == tiid.getIteration();
+    }
+
+    @Override
+    public String toString() {
+        return tid.toString() + " iteration:" + iteration;
+    }
+}
diff --git a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/util/IterationUtils.java b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/util/IterationUtils.java
index 02097bf..8052b7c 100644
--- a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/util/IterationUtils.java
+++ b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/util/IterationUtils.java
@@ -28,73 +28,66 @@
 import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
 import edu.uci.ics.hyracks.api.dataflow.state.IStateObject;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
-import edu.uci.ics.hyracks.api.job.JobId;
 import edu.uci.ics.pregelix.api.job.PregelixJob;
 import edu.uci.ics.pregelix.api.util.BspUtils;
 import edu.uci.ics.pregelix.api.util.JobStateUtils;
 import edu.uci.ics.pregelix.dataflow.context.RuntimeContext;
-import edu.uci.ics.pregelix.dataflow.context.StateKey;
+import edu.uci.ics.pregelix.dataflow.context.TaskIterationID;
 
 public class IterationUtils {
     public static final String TMP_DIR = "/tmp/";
 
-    public static void setIterationState(IHyracksTaskContext ctx, int partition, IStateObject state) {
+    public static void setIterationState(IHyracksTaskContext ctx, String pregelixJobId, int partition, int iteration,
+            IStateObject state) {
         INCApplicationContext appContext = ctx.getJobletContext().getApplicationContext();
         RuntimeContext context = (RuntimeContext) appContext.getApplicationObject();
-        Map<StateKey, IStateObject> map = context.getAppStateStore();
-        map.put(new StateKey(ctx.getJobletContext().getJobId(), partition), state);
+        Map<TaskIterationID, IStateObject> map = context.getAppStateStore(pregelixJobId);
+        map.put(new TaskIterationID(pregelixJobId, partition, iteration), state);
     }
 
-    public static IStateObject getIterationState(IHyracksTaskContext ctx, int partition) {
-        JobId currentId = ctx.getJobletContext().getJobId();
-        JobId lastId = new JobId(currentId.getId() - 1);
+    public static IStateObject getIterationState(IHyracksTaskContext ctx, String pregelixJobId, int partition,
+            int iteration) {
         INCApplicationContext appContext = ctx.getJobletContext().getApplicationContext();
         RuntimeContext context = (RuntimeContext) appContext.getApplicationObject();
-        Map<StateKey, IStateObject> map = context.getAppStateStore();
-        IStateObject state = map.get(new StateKey(lastId, partition));
-        while (state == null) {
-            /** in case the last job is a checkpointing job */
-            lastId = new JobId(lastId.getId() - 1);
-            state = map.get(new StateKey(lastId, partition));
-        }
+        Map<TaskIterationID, IStateObject> map = context.getAppStateStore(pregelixJobId);
+        IStateObject state = map.get(new TaskIterationID(pregelixJobId, partition, iteration));
         return state;
     }
 
-    public static void removeIterationState(IHyracksTaskContext ctx, int partition) {
-        JobId currentId = ctx.getJobletContext().getJobId();
-        JobId lastId = new JobId(currentId.getId() - 1);
+    public static void removeIterationState(IHyracksTaskContext ctx, String pregelixJobId, int partition, int iteration) {
         INCApplicationContext appContext = ctx.getJobletContext().getApplicationContext();
         RuntimeContext context = (RuntimeContext) appContext.getApplicationObject();
-        Map<StateKey, IStateObject> map = context.getAppStateStore();
-        map.remove(new StateKey(lastId, partition));
+        Map<TaskIterationID, IStateObject> map = context.getAppStateStore(pregelixJobId);
+        map.remove(new TaskIterationID(pregelixJobId, partition, iteration));
     }
 
-    public static void endSuperStep(String giraphJobId, IHyracksTaskContext ctx) {
+    public static void endSuperStep(String pregelixJobId, IHyracksTaskContext ctx) {
         INCApplicationContext appContext = ctx.getJobletContext().getApplicationContext();
         RuntimeContext context = (RuntimeContext) appContext.getApplicationObject();
-        context.endSuperStep(giraphJobId);
+        context.endSuperStep(pregelixJobId);
     }
 
-    public static void setProperties(String jobId, IHyracksTaskContext ctx, Configuration conf, long currentIteration) {
-        INCApplicationContext appContext = ctx.getJobletContext().getApplicationContext();
-        RuntimeContext context = (RuntimeContext) appContext.getApplicationObject();
-        context.setVertexProperties(jobId, conf.getLong(PregelixJob.NUM_VERTICE, -1),
-                conf.getLong(PregelixJob.NUM_EDGES, -1), currentIteration);
-    }
-
-    public static void recoverProperties(String jobId, IHyracksTaskContext ctx, Configuration conf,
+    public static void setProperties(String pregelixJobId, IHyracksTaskContext ctx, Configuration conf,
             long currentIteration) {
         INCApplicationContext appContext = ctx.getJobletContext().getApplicationContext();
         RuntimeContext context = (RuntimeContext) appContext.getApplicationObject();
-        context.recoverVertexProperties(jobId, conf.getLong(PregelixJob.NUM_VERTICE, -1),
-                conf.getLong(PregelixJob.NUM_EDGES, -1), currentIteration);
+        context.setVertexProperties(pregelixJobId, conf.getLong(PregelixJob.NUM_VERTICE, -1),
+                conf.getLong(PregelixJob.NUM_EDGES, -1), currentIteration, ctx.getJobletContext().getClassLoader());
     }
 
-    public static void writeTerminationState(Configuration conf, String jobId, boolean terminate)
+    public static void recoverProperties(String pregelixJobId, IHyracksTaskContext ctx, Configuration conf,
+            long currentIteration) {
+        INCApplicationContext appContext = ctx.getJobletContext().getApplicationContext();
+        RuntimeContext context = (RuntimeContext) appContext.getApplicationObject();
+        context.recoverVertexProperties(pregelixJobId, conf.getLong(PregelixJob.NUM_VERTICE, -1),
+                conf.getLong(PregelixJob.NUM_EDGES, -1), currentIteration, ctx.getJobletContext().getClassLoader());
+    }
+
+    public static void writeTerminationState(Configuration conf, String pregelixJobId, boolean terminate)
             throws HyracksDataException {
         try {
             FileSystem dfs = FileSystem.get(conf);
-            String pathStr = IterationUtils.TMP_DIR + jobId;
+            String pathStr = IterationUtils.TMP_DIR + pregelixJobId;
             Path path = new Path(pathStr);
             FSDataOutputStream output = dfs.create(path, true);
             output.writeBoolean(terminate);
@@ -105,11 +98,11 @@
         }
     }
 
-    public static void writeGlobalAggregateValue(Configuration conf, String jobId, Writable agg)
+    public static void writeGlobalAggregateValue(Configuration conf, String pregelixJobId, Writable agg)
             throws HyracksDataException {
         try {
             FileSystem dfs = FileSystem.get(conf);
-            String pathStr = IterationUtils.TMP_DIR + jobId + "agg";
+            String pathStr = IterationUtils.TMP_DIR + pregelixJobId + "agg";
             Path path = new Path(pathStr);
             FSDataOutputStream output = dfs.create(path, true);
             agg.write(output);
@@ -120,10 +113,10 @@
         }
     }
 
-    public static boolean readTerminationState(Configuration conf, String jobId) throws HyracksDataException {
+    public static boolean readTerminationState(Configuration conf, String pregelixJobId) throws HyracksDataException {
         try {
             FileSystem dfs = FileSystem.get(conf);
-            String pathStr = IterationUtils.TMP_DIR + jobId;
+            String pathStr = IterationUtils.TMP_DIR + pregelixJobId;
             Path path = new Path(pathStr);
             FSDataInputStream input = dfs.open(path);
             boolean terminate = input.readBoolean();
@@ -134,8 +127,8 @@
         }
     }
 
-    public static void writeForceTerminationState(Configuration conf, String jobId) throws HyracksDataException {
-        JobStateUtils.writeForceTerminationState(conf, jobId);
+    public static void writeForceTerminationState(Configuration conf, String pregelixJobId) throws HyracksDataException {
+        JobStateUtils.writeForceTerminationState(conf, pregelixJobId);
     }
 
     public static boolean readForceTerminationState(Configuration conf, String jobId) throws HyracksDataException {
diff --git a/pregelix/pregelix-example/data/update/webmap_link.txt b/pregelix/pregelix-example/data/update/webmap_link.txt
new file mode 100644
index 0000000..9812045
--- /dev/null
+++ b/pregelix/pregelix-example/data/update/webmap_link.txt
@@ -0,0 +1,10000 @@
+1
+2
+3
+4
+5
+6
+7
+8
+9
+10
+11
+12
+13
+14
+15
+16
+17
+18
+19
+20
+21
+22
+23
+24
+25
+26
+27
+28
+29
+30
+31
+32
+33
+34
+35
+36
+37
+38
+39
+40
+41
+42
+43
+44
+45
+46
+47
+48
+49
+50
+51
+52
+53
+54
+55
+56
+57
+58
+59
+60
+61
+62
+63
+64
+65
+66
+67
+68
+69
+70
+71
+72
+73
+74
+75
+76
+77
+78
+79
+80
+81
+82
+83
+84
+85
+86
+87
+88
+89
+90
+91
+92
+93
+94
+95
+96
+97
+98
+99
+100
+101
+102
+103
+104
+105
+106
+107
+108
+109
+110
+111
+112
+113
+114
+115
+116
+117
+118
+119
+120
+121
+122
+123
+124
+125
+126
+127
+128
+129
+130
+131
+132
+133
+134
+135
+136
+137
+138
+139
+140
+141
+142
+143
+144
+145
+146
+147
+148
+149
+150
+151
+152
+153
+154
+155
+156
+157
+158
+159
+160
+161
+162
+163
+164
+165
+166
+167
+168
+169
+170
+171
+172
+173
+174
+175
+176
+177
+178
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diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/PageRankVertex.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/PageRankVertex.java
index a866c1c..2508a1e 100644
--- a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/PageRankVertex.java
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/PageRankVertex.java
@@ -218,6 +218,7 @@
         job.setVertexOutputFormatClass(SimplePageRankVertexOutputFormat.class);
         job.setMessageCombinerClass(PageRankVertex.SimpleSumCombiner.class);
         job.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+        job.setFixedVertexValueSize(true);
         Client.run(args, job);
     }
 
diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/ReachabilityVertex.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/ReachabilityVertex.java
index 1bb33b8..fa16ce5 100644
--- a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/ReachabilityVertex.java
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/ReachabilityVertex.java
@@ -87,6 +87,7 @@
 
     private ByteWritable tmpVertexValue = new ByteWritable();
     private long sourceId = -1;
+    private long destId = -1;
 
     /** The source vertex id */
     public static final String SOURCE_ID = "ReachibilityVertex.sourceId";
@@ -112,7 +113,7 @@
      * @return True if the source id
      */
     private boolean isDest(VLongWritable v) {
-        return (v.get() == getContext().getConfiguration().getLong(DEST_ID, DEST_ID_DEFAULT));
+        return (v.get() == destId);
     }
 
     @Override
@@ -120,6 +121,9 @@
         if (sourceId < 0) {
             sourceId = getContext().getConfiguration().getLong(SOURCE_ID, SOURCE_ID_DEFAULT);
         }
+        if (destId < 0) {
+            destId = getContext().getConfiguration().getLong(DEST_ID, DEST_ID_DEFAULT);
+        }
         if (getSuperstep() == 1) {
             boolean isSource = isSource(getVertexId());
             if (isSource) {
diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/ShortestPathsVertex.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/ShortestPathsVertex.java
index 648f168..2fea813 100644
--- a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/ShortestPathsVertex.java
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/ShortestPathsVertex.java
@@ -16,8 +16,6 @@
 package edu.uci.ics.pregelix.example;
 
 import java.util.Iterator;
-import java.util.logging.Level;
-import java.util.logging.Logger;
 
 import org.apache.hadoop.io.FloatWritable;
 
@@ -84,12 +82,12 @@
 
     private DoubleWritable outputValue = new DoubleWritable();
     private DoubleWritable tmpVertexValue = new DoubleWritable();
-    /** Class logger */
-    private static final Logger LOG = Logger.getLogger(ShortestPathsVertex.class.getName());
     /** The shortest paths id */
     public static final String SOURCE_ID = "SimpleShortestPathsVertex.sourceId";
     /** Default shortest paths id */
     public static final long SOURCE_ID_DEFAULT = 1;
+    /** the source vertex id */
+    private long sourceId = -1;
 
     /**
      * Is this vertex the source id?
@@ -97,11 +95,14 @@
      * @return True if the source id
      */
     private boolean isSource() {
-        return (getVertexId().get() == getContext().getConfiguration().getLong(SOURCE_ID, SOURCE_ID_DEFAULT));
+        return (getVertexId().get() == sourceId);
     }
 
     @Override
     public void compute(Iterator<DoubleWritable> msgIterator) {
+        if (sourceId < 0) {
+            sourceId = getContext().getConfiguration().getLong(SOURCE_ID, SOURCE_ID_DEFAULT);
+        }
         if (getSuperstep() == 1) {
             tmpVertexValue.set(Double.MAX_VALUE);
             setVertexValue(tmpVertexValue);
@@ -110,17 +111,10 @@
         while (msgIterator.hasNext()) {
             minDist = Math.min(minDist, msgIterator.next().get());
         }
-        if (LOG.getLevel() == Level.FINE) {
-            LOG.fine("Vertex " + getVertexId() + " got minDist = " + minDist + " vertex value = " + getVertexValue());
-        }
         if (minDist < getVertexValue().get()) {
             tmpVertexValue.set(minDist);
             setVertexValue(tmpVertexValue);
             for (Edge<VLongWritable, FloatWritable> edge : getEdges()) {
-                if (LOG.getLevel() == Level.FINE) {
-                    LOG.fine("Vertex " + getVertexId() + " sent to " + edge.getDestVertexId() + " = "
-                            + (minDist + edge.getEdgeValue().get()));
-                }
                 outputValue.set(minDist + edge.getEdgeValue().get());
                 sendMsg(edge.getDestVertexId(), outputValue);
             }
diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/inputformat/TextShortestPathsInputFormat.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/inputformat/TextShortestPathsInputFormat.java
index 3ea4a9f..8987393 100644
--- a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/inputformat/TextShortestPathsInputFormat.java
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/inputformat/TextShortestPathsInputFormat.java
@@ -73,6 +73,7 @@
 
         vertex.getMsgList().clear();
         vertex.getEdges().clear();
+        vertex.reset();
         Text line = getRecordReader().getCurrentValue();
         String[] fields = line.toString().split(separator);
 
diff --git a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/FailureRecoveryInnerJoinTest.java b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/FailureRecoveryInnerJoinTest.java
index ff1e29f..421f2f5 100644
--- a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/FailureRecoveryInnerJoinTest.java
+++ b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/FailureRecoveryInnerJoinTest.java
@@ -56,6 +56,7 @@
             FileOutputFormat.setOutputPath(job, new Path(OUTPUTPAH));
             job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 20);
             job.setCheckpointHook(ConservativeCheckpointHook.class);
+            job.setFixedVertexValueSize(true);
 
             testCluster.setUp();
             Driver driver = new Driver(PageRankVertex.class);
diff --git a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/FailureRecoveryTest.java b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/FailureRecoveryTest.java
index 3fdaf15..b3ad112 100644
--- a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/FailureRecoveryTest.java
+++ b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/FailureRecoveryTest.java
@@ -55,6 +55,7 @@
             FileOutputFormat.setOutputPath(job, new Path(OUTPUTPAH));
             job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 20);
             job.setCheckpointHook(ConservativeCheckpointHook.class);
+            job.setFixedVertexValueSize(true);
 
             testCluster.setUp();
             Driver driver = new Driver(PageRankVertex.class);
diff --git a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/FailureRecoveryWithoutCheckpointTest.java b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/FailureRecoveryWithoutCheckpointTest.java
index e006ccd..9a2ef2c 100644
--- a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/FailureRecoveryWithoutCheckpointTest.java
+++ b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/FailureRecoveryWithoutCheckpointTest.java
@@ -53,6 +53,7 @@
             FileInputFormat.setInputPaths(job, INPUTPATH);
             FileOutputFormat.setOutputPath(job, new Path(OUTPUTPAH));
             job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 20);
+            job.setFixedVertexValueSize(true);
 
             testCluster.setUp();
             Driver driver = new Driver(PageRankVertex.class);
diff --git a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/MultiJobConnectedComponentsTest.java b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/MultiJobConnectedComponentsTest.java
new file mode 100644
index 0000000..65b9845
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/MultiJobConnectedComponentsTest.java
@@ -0,0 +1,103 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.pregelix.example;
+
+import java.io.File;
+
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
+import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
+import org.junit.Test;
+
+import edu.uci.ics.pregelix.api.job.PregelixJob;
+import edu.uci.ics.pregelix.api.util.ConservativeCheckpointHook;
+import edu.uci.ics.pregelix.api.util.DefaultVertexPartitioner;
+import edu.uci.ics.pregelix.core.driver.Driver;
+import edu.uci.ics.pregelix.core.util.PregelixHyracksIntegrationUtil;
+import edu.uci.ics.pregelix.example.ConnectedComponentsVertex.SimpleConnectedComponentsVertexOutputFormat;
+import edu.uci.ics.pregelix.example.data.VLongNormalizedKeyComputer;
+import edu.uci.ics.pregelix.example.inputformat.TextConnectedComponentsInputFormat;
+import edu.uci.ics.pregelix.example.util.TestCluster;
+import edu.uci.ics.pregelix.example.util.TestUtils;
+
+/**
+ * This test case tests multi-user workload, using ConnectedComponents.
+ * 
+ * @author yingyib
+ */
+public class MultiJobConnectedComponentsTest {
+    private static String INPUTPATH = "data/webmapcomplex";
+    private static String OUTPUTPAH = "actual/result";
+    private static String OUTPUTPAH2 = "actual/result2";
+    private static String EXPECTEDPATH = "src/test/resources/expected/ConnectedComponentsRealComplex";
+
+    @Test
+    public void test() throws Exception {
+        TestCluster testCluster = new TestCluster();
+        try {
+            PregelixJob job = new PregelixJob(ConnectedComponentsVertex.class.getName());
+            job.setVertexClass(ConnectedComponentsVertex.class);
+            job.setVertexClass(ConnectedComponentsVertex.class);
+            job.setVertexInputFormatClass(TextConnectedComponentsInputFormat.class);
+            job.setVertexOutputFormatClass(SimpleConnectedComponentsVertexOutputFormat.class);
+            job.setMessageCombinerClass(ConnectedComponentsVertex.SimpleMinCombiner.class);
+            job.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+            job.setVertexPartitionerClass(DefaultVertexPartitioner.class);
+            job.setDynamicVertexValueSize(true);
+            FileInputFormat.setInputPaths(job, INPUTPATH);
+            FileOutputFormat.setOutputPath(job, new Path(OUTPUTPAH));
+            job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 23);
+            job.setCheckpointHook(ConservativeCheckpointHook.class);
+
+            testCluster.setUp();
+            Thread thread = new Thread(new Runnable() {
+
+                @Override
+                public void run() {
+                    try {
+                        Driver driver = new Driver(PageRankVertex.class);
+                        PregelixJob job2 = new PregelixJob(ConnectedComponentsVertex.class.getName());
+                        job2.setVertexClass(ConnectedComponentsVertex.class);
+                        job2.setVertexClass(ConnectedComponentsVertex.class);
+                        job2.setVertexInputFormatClass(TextConnectedComponentsInputFormat.class);
+                        job2.setVertexOutputFormatClass(SimpleConnectedComponentsVertexOutputFormat.class);
+                        job2.setMessageCombinerClass(ConnectedComponentsVertex.SimpleMinCombiner.class);
+                        job2.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+                        job2.setVertexPartitionerClass(DefaultVertexPartitioner.class);
+                        job2.setDynamicVertexValueSize(true);
+                        FileInputFormat.setInputPaths(job2, INPUTPATH);
+                        FileOutputFormat.setOutputPath(job2, new Path(OUTPUTPAH2));
+                        job2.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 23);
+                        job2.setCheckpointHook(ConservativeCheckpointHook.class);
+                        driver.runJob(job2, "127.0.0.1", PregelixHyracksIntegrationUtil.TEST_HYRACKS_CC_CLIENT_PORT);
+                        TestUtils.compareWithResultDir(new File(EXPECTEDPATH), new File(OUTPUTPAH2));
+                    } catch (Exception e) {
+                        throw new IllegalStateException(e);
+                    }
+                }
+            });
+            thread.start();
+            Driver driver = new Driver(PageRankVertex.class);
+            driver.runJob(job, "127.0.0.1", PregelixHyracksIntegrationUtil.TEST_HYRACKS_CC_CLIENT_PORT);
+            TestUtils.compareWithResultDir(new File(EXPECTEDPATH), new File(OUTPUTPAH));
+            thread.join();
+        } catch (Exception e) {
+            PregelixHyracksIntegrationUtil.deinit();
+            testCluster.cleanupHDFS();
+            throw e;
+        }
+    }
+}
diff --git a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/MultiJobPageRankTest.java b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/MultiJobPageRankTest.java
new file mode 100644
index 0000000..cfd1b27
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/MultiJobPageRankTest.java
@@ -0,0 +1,98 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.pregelix.example;
+
+import java.io.File;
+
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
+import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
+import org.junit.Test;
+
+import edu.uci.ics.pregelix.api.job.PregelixJob;
+import edu.uci.ics.pregelix.api.util.ConservativeCheckpointHook;
+import edu.uci.ics.pregelix.core.driver.Driver;
+import edu.uci.ics.pregelix.core.util.PregelixHyracksIntegrationUtil;
+import edu.uci.ics.pregelix.example.PageRankVertex.SimplePageRankVertexOutputFormat;
+import edu.uci.ics.pregelix.example.data.VLongNormalizedKeyComputer;
+import edu.uci.ics.pregelix.example.inputformat.TextPageRankInputFormat;
+import edu.uci.ics.pregelix.example.util.TestCluster;
+import edu.uci.ics.pregelix.example.util.TestUtils;
+
+/**
+ * This test case tests multi-user workload, using PageRank.
+ * 
+ * @author yingyib
+ */
+public class MultiJobPageRankTest {
+    private static String INPUTPATH = "data/webmap";
+    private static String OUTPUTPAH = "actual/result";
+    private static String OUTPUTPAH2 = "actual/result2";
+    private static String EXPECTEDPATH = "src/test/resources/expected/PageRankReal";
+
+    @Test
+    public void test() throws Exception {
+        TestCluster testCluster = new TestCluster();
+        try {
+            PregelixJob job = new PregelixJob(PageRankVertex.class.getName());
+            job.setVertexClass(PageRankVertex.class);
+            job.setVertexInputFormatClass(TextPageRankInputFormat.class);
+            job.setVertexOutputFormatClass(SimplePageRankVertexOutputFormat.class);
+            job.setMessageCombinerClass(PageRankVertex.SimpleSumCombiner.class);
+            job.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+            FileInputFormat.setInputPaths(job, INPUTPATH);
+            FileOutputFormat.setOutputPath(job, new Path(OUTPUTPAH));
+            job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 20);
+            job.setCheckpointHook(ConservativeCheckpointHook.class);
+            job.setFixedVertexValueSize(true);
+
+            testCluster.setUp();
+            Thread thread = new Thread(new Runnable() {
+
+                @Override
+                public void run() {
+                    try {
+                        Driver driver = new Driver(PageRankVertex.class);
+                        PregelixJob job2 = new PregelixJob(PageRankVertex.class.getName());
+                        job2.setVertexClass(PageRankVertex.class);
+                        job2.setVertexInputFormatClass(TextPageRankInputFormat.class);
+                        job2.setVertexOutputFormatClass(SimplePageRankVertexOutputFormat.class);
+                        job2.setMessageCombinerClass(PageRankVertex.SimpleSumCombiner.class);
+                        job2.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+                        FileInputFormat.setInputPaths(job2, INPUTPATH);
+                        FileOutputFormat.setOutputPath(job2, new Path(OUTPUTPAH2));
+                        job2.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 20);
+                        job2.setCheckpointHook(ConservativeCheckpointHook.class);
+                        job2.setFixedVertexValueSize(true);
+                        driver.runJob(job2, "127.0.0.1", PregelixHyracksIntegrationUtil.TEST_HYRACKS_CC_CLIENT_PORT);
+                        TestUtils.compareWithResultDir(new File(EXPECTEDPATH), new File(OUTPUTPAH2));
+                    } catch (Exception e) {
+                        throw new IllegalStateException(e);
+                    }
+                }
+            });
+            thread.start();
+            Driver driver = new Driver(PageRankVertex.class);
+            driver.runJob(job, "127.0.0.1", PregelixHyracksIntegrationUtil.TEST_HYRACKS_CC_CLIENT_PORT);
+            TestUtils.compareWithResultDir(new File(EXPECTEDPATH), new File(OUTPUTPAH));
+            thread.join();
+        } catch (Exception e) {
+            PregelixHyracksIntegrationUtil.deinit();
+            testCluster.cleanupHDFS();
+            throw e;
+        }
+    }
+}
diff --git a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/UpdateVertex.java b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/UpdateVertex.java
new file mode 100644
index 0000000..1e6359d
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/UpdateVertex.java
@@ -0,0 +1,106 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.pregelix.example;
+
+import java.util.Iterator;
+import java.util.Random;
+
+import org.apache.hadoop.io.FloatWritable;
+import org.apache.hadoop.io.Text;
+
+import edu.uci.ics.pregelix.api.graph.Vertex;
+import edu.uci.ics.pregelix.example.io.VLongWritable;
+
+/**
+ * @author yingyib
+ */
+public class UpdateVertex extends Vertex<VLongWritable, Text, FloatWritable, VLongWritable> {
+    private final int MAX_VALUE_SIZE = 32768 / 2;
+    private VLongWritable msg = new VLongWritable();
+    private Text tempValue = new Text();
+    private Random rand = new Random();
+
+    @Override
+    public void compute(Iterator<VLongWritable> msgIterator) throws Exception {
+        if (getSuperstep() == 1) {
+            updateAndSendMsg();
+        } else if (getSuperstep() > 1 && getSuperstep() < 2) {
+            verifyVertexSize(msgIterator);
+            updateAndSendMsg();
+        } else {
+            voteToHalt();
+        }
+    }
+
+    private void verifyVertexSize(Iterator<VLongWritable> msgIterator) {
+        if (!msgIterator.hasNext()) {
+            throw new IllegalStateException("no message for vertex " + " " + getVertexId() + " " + getVertexValue());
+        }
+        /**
+         * verify the size
+         */
+        int valueSize = getVertexValue().toString().toCharArray().length;
+        long expectedValueSize = msgIterator.next().get();
+        if (valueSize != expectedValueSize) {
+            if (valueSize == -expectedValueSize) {
+                //verify fixed size update
+                char[] valueCharArray = getVertexValue().toString().toCharArray();
+                for (int i = 0; i < valueCharArray.length; i++) {
+                    if (valueCharArray[i] != 'b') {
+                        throw new IllegalStateException("vertex id: " + getVertexId()
+                                + " has a un-propagated update in the last iteration");
+                    }
+                }
+            } else {
+                throw new IllegalStateException("vertex id: " + getVertexId() + " vertex value size:" + valueSize
+                        + ", expected value size:" + expectedValueSize);
+            }
+        }
+        if (msgIterator.hasNext()) {
+            throw new IllegalStateException("more than one message for vertex " + " " + getVertexId() + " "
+                    + getVertexValue());
+        }
+    }
+
+    private void updateAndSendMsg() {
+        int newValueSize = rand.nextInt(MAX_VALUE_SIZE);
+        char[] charArray = new char[newValueSize];
+        for (int i = 0; i < charArray.length; i++) {
+            charArray[i] = 'a';
+        }
+        /**
+         * set a self-message
+         */
+        msg.set(newValueSize);
+        boolean fixedSize = getVertexId().get() < 2000;
+        if (fixedSize) {
+            int oldSize = getVertexValue().toString().toCharArray().length;
+            charArray = new char[oldSize];
+            for (int i = 0; i < oldSize; i++) {
+                charArray[i] = 'b';
+            }
+            msg.set(-oldSize);
+        }
+
+        /**
+         * set the vertex value
+         */
+        tempValue.set(new String(charArray));
+        setVertexValue(tempValue);
+
+        sendMsg(getVertexId(), msg);
+        activate();
+    }
+}
diff --git a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/UpdateVertexInputFormat.java b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/UpdateVertexInputFormat.java
new file mode 100644
index 0000000..076337a
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/UpdateVertexInputFormat.java
@@ -0,0 +1,112 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.pregelix.example;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.io.FloatWritable;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.mapreduce.InputSplit;
+import org.apache.hadoop.mapreduce.JobContext;
+import org.apache.hadoop.mapreduce.TaskAttemptContext;
+import org.apache.hadoop.mapreduce.lib.input.FileSplit;
+
+import edu.uci.ics.pregelix.api.graph.Vertex;
+import edu.uci.ics.pregelix.api.io.VertexInputFormat;
+import edu.uci.ics.pregelix.api.io.VertexReader;
+import edu.uci.ics.pregelix.api.util.BspUtils;
+import edu.uci.ics.pregelix.example.io.DoubleWritable;
+import edu.uci.ics.pregelix.example.io.VLongWritable;
+
+public class UpdateVertexInputFormat extends VertexInputFormat<VLongWritable, Text, FloatWritable, DoubleWritable> {
+
+    @Override
+    public VertexReader<VLongWritable, Text, FloatWritable, DoubleWritable> createVertexReader(InputSplit split,
+            TaskAttemptContext context) throws IOException {
+        return new UpdateVertexReader(context);
+    }
+
+    @Override
+    public List<InputSplit> getSplits(JobContext context, int numWorkers) throws IOException, InterruptedException {
+        InputSplit split = new FileSplit(new Path("testdata"), 0, 0, new String[0]);
+        return Collections.singletonList(split);
+    }
+}
+
+@SuppressWarnings("rawtypes")
+class UpdateVertexReader implements VertexReader<VLongWritable, Text, FloatWritable, DoubleWritable> {
+
+    private final static int MAX_ID = 65536;
+    private final static int MIN_ID = -65536;
+    private Vertex vertex;
+    private VLongWritable vertexId = new VLongWritable();
+    private int currentId = MIN_ID;
+    private TaskAttemptContext context;
+
+    public UpdateVertexReader(TaskAttemptContext context) {
+        this.context = context;
+    }
+
+    private TaskAttemptContext getContext() {
+        return context;
+    }
+
+    @Override
+    public boolean nextVertex() throws IOException, InterruptedException {
+        return currentId < MAX_ID;
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Vertex<VLongWritable, Text, FloatWritable, DoubleWritable> getCurrentVertex() throws IOException,
+            InterruptedException {
+        if (vertex == null)
+            vertex = (Vertex) BspUtils.createVertex(getContext().getConfiguration());
+        vertex.getMsgList().clear();
+        vertex.getEdges().clear();
+
+        vertex.reset();
+
+        /**
+         * set the src vertex id
+         */
+        vertexId.set(currentId++);
+        vertex.setVertexId(vertexId);
+
+        /**
+         * set the vertex value
+         */
+        vertex.setVertexValue(new Text("aaa"));
+        return vertex;
+    }
+
+    @Override
+    public void initialize(InputSplit inputSplit, TaskAttemptContext context) throws IOException, InterruptedException {
+
+    }
+
+    @Override
+    public void close() throws IOException {
+
+    }
+
+    @Override
+    public float getProgress() throws IOException, InterruptedException {
+        return 0;
+    }
+}
\ No newline at end of file
diff --git a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/UpdateVertexOutputFormat.java b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/UpdateVertexOutputFormat.java
new file mode 100644
index 0000000..493a33e
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/UpdateVertexOutputFormat.java
@@ -0,0 +1,54 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.pregelix.example;
+
+import java.io.IOException;
+
+import org.apache.hadoop.io.FloatWritable;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.mapreduce.RecordWriter;
+import org.apache.hadoop.mapreduce.TaskAttemptContext;
+
+import edu.uci.ics.pregelix.api.graph.Vertex;
+import edu.uci.ics.pregelix.api.io.VertexWriter;
+import edu.uci.ics.pregelix.api.io.text.TextVertexOutputFormat;
+import edu.uci.ics.pregelix.example.io.VLongWritable;
+
+public class UpdateVertexOutputFormat extends TextVertexOutputFormat<VLongWritable, Text, FloatWritable> {
+
+    @Override
+    public VertexWriter<VLongWritable, Text, FloatWritable> createVertexWriter(TaskAttemptContext context)
+            throws IOException, InterruptedException {
+        final RecordWriter<Text, Text> recordWriter = textOutputFormat.getRecordWriter(context);
+        return new UpdateVertexWriter(recordWriter);
+    }
+
+    /**
+     * Simple VertexWriter that support
+     */
+    public static class UpdateVertexWriter extends TextVertexWriter<VLongWritable, Text, FloatWritable> {
+        public UpdateVertexWriter(RecordWriter<Text, Text> lineRecordWriter) {
+            super(lineRecordWriter);
+        }
+
+        @Override
+        public void writeVertex(Vertex<VLongWritable, Text, FloatWritable, ?> vertex) throws IOException,
+                InterruptedException {
+            int len = vertex.getVertexValue().toString().toCharArray().length;
+            getRecordWriter().write(new Text(vertex.getVertexId().toString()), new Text(Integer.toString(len)));
+        }
+    }
+
+}
diff --git a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/UpdateVertexTest.java b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/UpdateVertexTest.java
new file mode 100644
index 0000000..6adc5bb
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/UpdateVertexTest.java
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.pregelix.example;
+
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
+import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
+import org.junit.Test;
+
+import edu.uci.ics.pregelix.api.job.PregelixJob;
+import edu.uci.ics.pregelix.core.base.IDriver.Plan;
+import edu.uci.ics.pregelix.core.driver.Driver;
+import edu.uci.ics.pregelix.core.util.PregelixHyracksIntegrationUtil;
+import edu.uci.ics.pregelix.example.util.TestCluster;
+
+/**
+ * This test case tests the error message propagation.
+ * 
+ * @author yingyib
+ */
+public class UpdateVertexTest {
+
+    private static String INPUT_PATH = "/data/webmap/";
+    private static String OUTPUT_PATH = "actual/resultcomplex";
+
+    @Test
+    public void test() throws Exception {
+        TestCluster testCluster = new TestCluster();
+        try {
+            PregelixJob job = new PregelixJob(UpdateVertex.class.getSimpleName());
+            job.setVertexClass(UpdateVertex.class);
+            job.setVertexInputFormatClass(UpdateVertexInputFormat.class);
+            job.setVertexOutputFormatClass(UpdateVertexOutputFormat.class);
+            job.setDynamicVertexValueSize(true);
+
+            FileInputFormat.setInputPaths(job, INPUT_PATH);
+            FileOutputFormat.setOutputPath(job, new Path(OUTPUT_PATH));
+            job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 23);
+
+            Driver driver = new Driver(UpdateVertex.class);
+            testCluster.setUp();
+
+            Plan[] plans = new Plan[] { Plan.INNER_JOIN, Plan.OUTER_JOIN };
+            for (Plan plan : plans) {
+                driver.runJob(job, plan, "127.0.0.1", PregelixHyracksIntegrationUtil.TEST_HYRACKS_CC_CLIENT_PORT, false);
+            }
+        } catch (Exception e) {
+            throw new IllegalStateException(e);
+        } finally {
+            testCluster.tearDown();
+        }
+    }
+
+}
diff --git a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/jobgen/JobGenerator.java b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/jobgen/JobGenerator.java
index f6857fe..2dfd071 100644
--- a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/jobgen/JobGenerator.java
+++ b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/jobgen/JobGenerator.java
@@ -74,6 +74,7 @@
         job.setVertexOutputFormatClass(SimplePageRankVertexOutputFormat.class);
         job.setMessageCombinerClass(PageRankVertex.SimpleSumCombiner.class);
         job.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+        job.setFixedVertexValueSize(true);
         FileInputFormat.setInputPaths(job, HDFS_INPUTPATH);
         FileOutputFormat.setOutputPath(job, new Path(HDFS_OUTPUTPAH));
         job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 20);
@@ -89,6 +90,7 @@
         job.setMessageCombinerClass(PageRankVertex.SimpleSumCombiner.class);
         job.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
         job.setVertexPartitionerClass(DefaultVertexPartitioner.class);
+        job.setFixedVertexValueSize(true);
         FileInputFormat.setInputPaths(job, HDFS_INPUTPATH2);
         FileOutputFormat.setOutputPath(job, new Path(HDFS_OUTPUTPAH2));
         job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 23);
@@ -116,6 +118,7 @@
         job.setVertexInputFormatClass(TextPageRankInputFormat.class);
         job.setVertexOutputFormatClass(SimplePageRankVertexOutputFormat.class);
         job.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+        job.setFixedVertexValueSize(true);
         FileInputFormat.setInputPaths(job, HDFS_INPUTPATH);
         FileOutputFormat.setOutputPath(job, new Path(HDFS_OUTPUTPAH));
         job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 20);
@@ -190,6 +193,7 @@
         job.setMessageCombinerClass(PageRankVertex.SimpleSumCombiner.class);
         job.setVertexOutputFormatClass(SimplePageRankVertexOutputFormat.class);
         job.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+        job.setFixedVertexValueSize(true);
         FileInputFormat.setInputPaths(job, HDFS_INPUTPATH);
         FileOutputFormat.setOutputPath(job, new Path(HDFS_OUTPUTPAH));
         job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 20);
diff --git a/pregelix/pregelix-example/src/test/resources/jobs/PageRank.xml b/pregelix/pregelix-example/src/test/resources/jobs/PageRank.xml
index 65e0b30..d29b2da 100644
--- a/pregelix/pregelix-example/src/test/resources/jobs/PageRank.xml
+++ b/pregelix/pregelix-example/src/test/resources/jobs/PageRank.xml
@@ -127,6 +127,7 @@
 <property><name>pregelix.vertexInputFormatClass</name><value>edu.uci.ics.pregelix.example.PageRankVertex$SimulatedPageRankVertexInputFormat</value></property>
 <property><name>mapred.job.queue.name</name><value>default</value></property>
 <property><name>mapred.job.tracker.persist.jobstatus.active</name><value>false</value></property>
+<property><name>pregelix.incStateLength</name><value>false</value></property>
 <property><name>mapred.reduce.slowstart.completed.maps</name><value>0.05</value></property>
 <property><name>topology.script.number.args</name><value>100</value></property>
 <property><name>mapred.skip.map.max.skip.records</name><value>0</value></property>
diff --git a/pregelix/pregelix-example/src/test/resources/jobs/PageRankReal.xml b/pregelix/pregelix-example/src/test/resources/jobs/PageRankReal.xml
index b50b02a..69f8154 100644
--- a/pregelix/pregelix-example/src/test/resources/jobs/PageRankReal.xml
+++ b/pregelix/pregelix-example/src/test/resources/jobs/PageRankReal.xml
@@ -128,6 +128,7 @@
 <property><name>pregelix.vertexInputFormatClass</name><value>edu.uci.ics.pregelix.example.inputformat.TextPageRankInputFormat</value></property>
 <property><name>mapred.job.queue.name</name><value>default</value></property>
 <property><name>mapred.job.tracker.persist.jobstatus.active</name><value>false</value></property>
+<property><name>pregelix.incStateLength</name><value>false</value></property>
 <property><name>mapred.reduce.slowstart.completed.maps</name><value>0.05</value></property>
 <property><name>topology.script.number.args</name><value>100</value></property>
 <property><name>mapred.skip.map.max.skip.records</name><value>0</value></property>
diff --git a/pregelix/pregelix-example/src/test/resources/jobs/PageRankRealComplex.xml b/pregelix/pregelix-example/src/test/resources/jobs/PageRankRealComplex.xml
index 217fbba..04fc686 100644
--- a/pregelix/pregelix-example/src/test/resources/jobs/PageRankRealComplex.xml
+++ b/pregelix/pregelix-example/src/test/resources/jobs/PageRankRealComplex.xml
@@ -1,145 +1,146 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?><configuration>
-<property><name>mapred.tasktracker.dns.nameserver</name><value>default</value></property>
-<property><name>mapred.queue.default.acl-administer-jobs</name><value>*</value></property>
-<property><name>mapred.skip.map.auto.incr.proc.count</name><value>true</value></property>
-<property><name>mapred.jobtracker.instrumentation</name><value>org.apache.hadoop.mapred.JobTrackerMetricsInst</value></property>
-<property><name>mapred.skip.reduce.auto.incr.proc.count</name><value>true</value></property>
-<property><name>fs.hsftp.impl</name><value>org.apache.hadoop.hdfs.HsftpFileSystem</value></property>
-<property><name>mapred.input.dir</name><value>file:/webmapcomplex</value></property>
-<property><name>mapred.submit.replication</name><value>10</value></property>
-<property><name>ipc.server.tcpnodelay</name><value>false</value></property>
-<property><name>fs.checkpoint.dir</name><value>${hadoop.tmp.dir}/dfs/namesecondary</value></property>
-<property><name>mapred.output.compression.type</name><value>RECORD</value></property>
-<property><name>mapred.job.shuffle.merge.percent</name><value>0.66</value></property>
-<property><name>mapred.child.java.opts</name><value>-Xmx200m</value></property>
-<property><name>mapred.queue.default.acl-submit-job</name><value>*</value></property>
-<property><name>keep.failed.task.files</name><value>false</value></property>
-<property><name>mapred.jobtracker.job.history.block.size</name><value>3145728</value></property>
-<property><name>io.bytes.per.checksum</name><value>512</value></property>
-<property><name>mapred.task.tracker.report.address</name><value>127.0.0.1:0</value></property>
-<property><name>hadoop.util.hash.type</name><value>murmur</value></property>
-<property><name>fs.hdfs.impl</name><value>org.apache.hadoop.hdfs.DistributedFileSystem</value></property>
-<property><name>fs.ramfs.impl</name><value>org.apache.hadoop.fs.InMemoryFileSystem</value></property>
-<property><name>mapred.jobtracker.restart.recover</name><value>false</value></property>
-<property><name>fs.hftp.impl</name><value>org.apache.hadoop.hdfs.HftpFileSystem</value></property>
-<property><name>fs.checkpoint.period</name><value>3600</value></property>
-<property><name>mapred.child.tmp</name><value>./tmp</value></property>
-<property><name>mapred.local.dir.minspacekill</name><value>0</value></property>
-<property><name>map.sort.class</name><value>org.apache.hadoop.util.QuickSort</value></property>
-<property><name>hadoop.logfile.count</name><value>10</value></property>
-<property><name>ipc.client.connection.maxidletime</name><value>10000</value></property>
-<property><name>mapred.output.dir</name><value>/resultcomplex</value></property>
-<property><name>io.map.index.skip</name><value>0</value></property>
-<property><name>mapred.tasktracker.expiry.interval</name><value>600000</value></property>
-<property><name>mapred.output.compress</name><value>false</value></property>
-<property><name>io.seqfile.lazydecompress</name><value>true</value></property>
-<property><name>mapred.reduce.parallel.copies</name><value>5</value></property>
-<property><name>fs.checkpoint.size</name><value>67108864</value></property>
-<property><name>mapred.job.reduce.input.buffer.percent</name><value>0.0</value></property>
-<property><name>mapred.job.name</name><value>PageRank</value></property>
-<property><name>pregelix.nmkComputerClass</name><value>edu.uci.ics.pregelix.example.data.VLongNormalizedKeyComputer</value></property>
-<property><name>local.cache.size</name><value>10737418240</value></property>
 <property><name>fs.s3n.impl</name><value>org.apache.hadoop.fs.s3native.NativeS3FileSystem</value></property>
-<property><name>mapred.userlog.limit.kb</name><value>0</value></property>
-<property><name>fs.file.impl</name><value>org.apache.hadoop.fs.LocalFileSystem</value></property>
-<property><name>mapred.task.tracker.http.address</name><value>0.0.0.0:50060</value></property>
-<property><name>mapred.task.timeout</name><value>600000</value></property>
-<property><name>fs.kfs.impl</name><value>org.apache.hadoop.fs.kfs.KosmosFileSystem</value></property>
-<property><name>mapred.max.tracker.blacklists</name><value>4</value></property>
-<property><name>fs.s3.buffer.dir</name><value>${hadoop.tmp.dir}/s3</value></property>
-<property><name>mapred.job.tracker.persist.jobstatus.dir</name><value>/jobtracker/jobsInfo</value></property>
-<property><name>ipc.client.kill.max</name><value>10</value></property>
-<property><name>mapred.tasktracker.instrumentation</name><value>org.apache.hadoop.mapred.TaskTrackerMetricsInst</value></property>
-<property><name>mapred.reduce.tasks.speculative.execution</name><value>true</value></property>
-<property><name>io.sort.record.percent</name><value>0.05</value></property>
-<property><name>hadoop.security.authorization</name><value>false</value></property>
-<property><name>mapred.max.tracker.failures</name><value>4</value></property>
-<property><name>mapred.jobtracker.taskScheduler</name><value>org.apache.hadoop.mapred.JobQueueTaskScheduler</value></property>
-<property><name>pregelix.numVertices</name><value>23</value></property>
-<property><name>mapred.tasktracker.dns.interface</name><value>default</value></property>
-<property><name>mapred.map.tasks</name><value>2</value></property>
-<property><name>mapred.job.tracker.persist.jobstatus.hours</name><value>0</value></property>
-<property><name>fs.s3.sleepTimeSeconds</name><value>10</value></property>
-<property><name>fs.default.name</name><value>file:///</value></property>
-<property><name>tasktracker.http.threads</name><value>40</value></property>
-<property><name>mapred.tasktracker.taskmemorymanager.monitoring-interval</name><value>5000</value></property>
-<property><name>hadoop.rpc.socket.factory.class.default</name><value>org.apache.hadoop.net.StandardSocketFactory</value></property>
-<property><name>mapred.reduce.tasks</name><value>1</value></property>
-<property><name>topology.node.switch.mapping.impl</name><value>org.apache.hadoop.net.ScriptBasedMapping</value></property>
-<property><name>pregelix.vertexClass</name><value>edu.uci.ics.pregelix.example.PageRankVertex</value></property>
-<property><name>mapred.skip.reduce.max.skip.groups</name><value>0</value></property>
-<property><name>io.file.buffer.size</name><value>4096</value></property>
-<property><name>mapred.jobtracker.maxtasks.per.job</name><value>-1</value></property>
-<property><name>mapred.tasktracker.indexcache.mb</name><value>10</value></property>
-<property><name>mapred.tasktracker.map.tasks.maximum</name><value>2</value></property>
-<property><name>fs.har.impl.disable.cache</name><value>true</value></property>
-<property><name>mapred.task.profile.maps</name><value>0-2</value></property>
-<property><name>hadoop.native.lib</name><value>true</value></property>
-<property><name>fs.s3.block.size</name><value>67108864</value></property>
-<property><name>mapred.job.reuse.jvm.num.tasks</name><value>1</value></property>
-<property><name>mapred.job.tracker.http.address</name><value>0.0.0.0:50030</value></property>
-<property><name>mapred.tasktracker.reduce.tasks.maximum</name><value>2</value></property>
-<property><name>io.compression.codecs</name><value>org.apache.hadoop.io.compress.DefaultCodec,org.apache.hadoop.io.compress.GzipCodec,org.apache.hadoop.io.compress.BZip2Codec</value></property>
-<property><name>mapred.job.shuffle.input.buffer.percent</name><value>0.70</value></property>
-<property><name>io.seqfile.compress.blocksize</name><value>1000000</value></property>
-<property><name>mapred.queue.names</name><value>default</value></property>
-<property><name>fs.har.impl</name><value>org.apache.hadoop.fs.HarFileSystem</value></property>
-<property><name>pregelix.checkpointHook</name><value>edu.uci.ics.pregelix.api.util.ConservativeCheckpointHook</value></property>
-<property><name>io.mapfile.bloom.error.rate</name><value>0.005</value></property>
-<property><name>mapred.job.tracker</name><value>local</value></property>
-<property><name>io.skip.checksum.errors</name><value>false</value></property>
-<property><name>mapred.reduce.max.attempts</name><value>4</value></property>
-<property><name>fs.s3.maxRetries</name><value>4</value></property>
-<property><name>ipc.server.listen.queue.size</name><value>128</value></property>
-<property><name>fs.trash.interval</name><value>0</value></property>
-<property><name>mapred.local.dir.minspacestart</name><value>0</value></property>
-<property><name>fs.s3.impl</name><value>org.apache.hadoop.fs.s3.S3FileSystem</value></property>
-<property><name>io.seqfile.sorter.recordlimit</name><value>1000000</value></property>
-<property><name>io.mapfile.bloom.size</name><value>1048576</value></property>
-<property><name>io.sort.mb</name><value>100</value></property>
-<property><name>mapred.local.dir</name><value>${hadoop.tmp.dir}/mapred/local</value></property>
-<property><name>io.sort.factor</name><value>10</value></property>
-<property><name>mapred.task.profile</name><value>false</value></property>
-<property><name>job.end.retry.interval</name><value>30000</value></property>
-<property><name>mapred.tasktracker.procfsbasedprocesstree.sleeptime-before-sigkill</name><value>5000</value></property>
-<property><name>mapred.jobtracker.completeuserjobs.maximum</name><value>100</value></property>
-<property><name>mapred.task.profile.reduces</name><value>0-2</value></property>
-<property><name>webinterface.private.actions</name><value>false</value></property>
-<property><name>hadoop.tmp.dir</name><value>/tmp/hadoop-${user.name}</value></property>
-<property><name>pregelix.combinerClass</name><value>edu.uci.ics.pregelix.example.PageRankVertex$SimpleSumCombiner</value></property>
-<property><name>mapred.output.compression.codec</name><value>org.apache.hadoop.io.compress.DefaultCodec</value></property>
-<property><name>mapred.skip.attempts.to.start.skipping</name><value>2</value></property>
-<property><name>mapred.temp.dir</name><value>${hadoop.tmp.dir}/mapred/temp</value></property>
-<property><name>mapred.merge.recordsBeforeProgress</name><value>10000</value></property>
-<property><name>mapred.map.output.compression.codec</name><value>org.apache.hadoop.io.compress.DefaultCodec</value></property>
-<property><name>mapred.compress.map.output</name><value>false</value></property>
-<property><name>io.sort.spill.percent</name><value>0.80</value></property>
-<property><name>fs.checkpoint.edits.dir</name><value>${fs.checkpoint.dir}</value></property>
-<property><name>mapred.userlog.retain.hours</name><value>24</value></property>
-<property><name>mapred.system.dir</name><value>${hadoop.tmp.dir}/mapred/system</value></property>
-<property><name>mapred.line.input.format.linespermap</name><value>1</value></property>
-<property><name>job.end.retry.attempts</name><value>0</value></property>
-<property><name>ipc.client.idlethreshold</name><value>4000</value></property>
-<property><name>pregelix.vertexOutputFormatClass</name><value>edu.uci.ics.pregelix.example.PageRankVertex$SimplePageRankVertexOutputFormat</value></property>
-<property><name>mapred.reduce.copy.backoff</name><value>300</value></property>
-<property><name>mapred.map.tasks.speculative.execution</name><value>true</value></property>
-<property><name>pregelix.partitionerClass</name><value>edu.uci.ics.pregelix.api.util.DefaultVertexPartitioner</value></property>
-<property><name>mapred.inmem.merge.threshold</name><value>1000</value></property>
-<property><name>hadoop.logfile.size</name><value>10000000</value></property>
-<property><name>pregelix.vertexInputFormatClass</name><value>edu.uci.ics.pregelix.example.inputformat.TextPageRankInputFormat</value></property>
-<property><name>mapred.job.queue.name</name><value>default</value></property>
-<property><name>mapred.job.tracker.persist.jobstatus.active</name><value>false</value></property>
-<property><name>mapred.reduce.slowstart.completed.maps</name><value>0.05</value></property>
-<property><name>topology.script.number.args</name><value>100</value></property>
-<property><name>mapred.skip.map.max.skip.records</name><value>0</value></property>
-<property><name>fs.ftp.impl</name><value>org.apache.hadoop.fs.ftp.FTPFileSystem</value></property>
 <property><name>mapred.task.cache.levels</name><value>2</value></property>
-<property><name>mapred.job.tracker.handler.count</name><value>10</value></property>
-<property><name>io.serializations</name><value>org.apache.hadoop.io.serializer.WritableSerialization</value></property>
-<property><name>ipc.client.connect.max.retries</name><value>10</value></property>
+<property><name>hadoop.tmp.dir</name><value>/tmp/hadoop-${user.name}</value></property>
+<property><name>hadoop.native.lib</name><value>true</value></property>
+<property><name>map.sort.class</name><value>org.apache.hadoop.util.QuickSort</value></property>
+<property><name>ipc.client.idlethreshold</name><value>4000</value></property>
+<property><name>mapred.system.dir</name><value>${hadoop.tmp.dir}/mapred/system</value></property>
+<property><name>mapred.job.tracker.persist.jobstatus.hours</name><value>0</value></property>
+<property><name>io.skip.checksum.errors</name><value>false</value></property>
+<property><name>fs.default.name</name><value>file:///</value></property>
+<property><name>mapred.child.tmp</name><value>./tmp</value></property>
+<property><name>fs.har.impl.disable.cache</name><value>true</value></property>
+<property><name>mapred.skip.reduce.max.skip.groups</name><value>0</value></property>
+<property><name>mapred.jobtracker.instrumentation</name><value>org.apache.hadoop.mapred.JobTrackerMetricsInst</value></property>
+<property><name>mapred.tasktracker.dns.nameserver</name><value>default</value></property>
+<property><name>io.sort.factor</name><value>10</value></property>
+<property><name>pregelix.checkpointHook</name><value>edu.uci.ics.pregelix.api.util.ConservativeCheckpointHook</value></property>
+<property><name>mapred.task.timeout</name><value>600000</value></property>
+<property><name>mapred.max.tracker.failures</name><value>4</value></property>
+<property><name>hadoop.rpc.socket.factory.class.default</name><value>org.apache.hadoop.net.StandardSocketFactory</value></property>
+<property><name>fs.hdfs.impl</name><value>org.apache.hadoop.hdfs.DistributedFileSystem</value></property>
+<property><name>mapred.queue.default.acl-administer-jobs</name><value>*</value></property>
+<property><name>mapred.queue.default.acl-submit-job</name><value>*</value></property>
+<property><name>mapred.skip.map.auto.incr.proc.count</name><value>true</value></property>
+<property><name>io.mapfile.bloom.size</name><value>1048576</value></property>
+<property><name>tasktracker.http.threads</name><value>40</value></property>
+<property><name>mapred.job.shuffle.merge.percent</name><value>0.66</value></property>
+<property><name>fs.ftp.impl</name><value>org.apache.hadoop.fs.ftp.FTPFileSystem</value></property>
+<property><name>pregelix.combinerClass</name><value>edu.uci.ics.pregelix.example.PageRankVertex$SimpleSumCombiner</value></property>
+<property><name>mapred.output.compress</name><value>false</value></property>
+<property><name>io.bytes.per.checksum</name><value>512</value></property>
+<property><name>topology.node.switch.mapping.impl</name><value>org.apache.hadoop.net.ScriptBasedMapping</value></property>
+<property><name>mapred.reduce.slowstart.completed.maps</name><value>0.05</value></property>
+<property><name>mapred.reduce.max.attempts</name><value>4</value></property>
+<property><name>fs.ramfs.impl</name><value>org.apache.hadoop.fs.InMemoryFileSystem</value></property>
+<property><name>mapred.skip.map.max.skip.records</name><value>0</value></property>
+<property><name>mapred.job.tracker.persist.jobstatus.dir</name><value>/jobtracker/jobsInfo</value></property>
+<property><name>fs.s3.buffer.dir</name><value>${hadoop.tmp.dir}/s3</value></property>
+<property><name>job.end.retry.attempts</name><value>0</value></property>
+<property><name>fs.file.impl</name><value>org.apache.hadoop.fs.LocalFileSystem</value></property>
+<property><name>mapred.local.dir.minspacestart</name><value>0</value></property>
+<property><name>mapred.output.compression.type</name><value>RECORD</value></property>
+<property><name>topology.script.number.args</name><value>100</value></property>
+<property><name>io.mapfile.bloom.error.rate</name><value>0.005</value></property>
+<property><name>mapred.max.tracker.blacklists</name><value>4</value></property>
+<property><name>pregelix.partitionerClass</name><value>edu.uci.ics.pregelix.api.util.DefaultVertexPartitioner</value></property>
+<property><name>mapred.task.profile.maps</name><value>0-2</value></property>
+<property><name>mapred.userlog.retain.hours</name><value>24</value></property>
+<property><name>pregelix.numVertices</name><value>23</value></property>
+<property><name>mapred.job.tracker.persist.jobstatus.active</name><value>false</value></property>
+<property><name>hadoop.security.authorization</name><value>false</value></property>
+<property><name>local.cache.size</name><value>10737418240</value></property>
 <property><name>mapred.min.split.size</name><value>0</value></property>
+<property><name>mapred.map.tasks</name><value>2</value></property>
+<property><name>mapred.child.java.opts</name><value>-Xmx200m</value></property>
+<property><name>mapred.job.queue.name</name><value>default</value></property>
+<property><name>ipc.server.listen.queue.size</name><value>128</value></property>
+<property><name>mapred.inmem.merge.threshold</name><value>1000</value></property>
+<property><name>job.end.retry.interval</name><value>30000</value></property>
+<property><name>mapred.skip.attempts.to.start.skipping</name><value>2</value></property>
+<property><name>fs.checkpoint.dir</name><value>${hadoop.tmp.dir}/dfs/namesecondary</value></property>
+<property><name>mapred.reduce.tasks</name><value>1</value></property>
+<property><name>mapred.merge.recordsBeforeProgress</name><value>10000</value></property>
+<property><name>mapred.userlog.limit.kb</name><value>0</value></property>
+<property><name>webinterface.private.actions</name><value>false</value></property>
+<property><name>io.sort.spill.percent</name><value>0.80</value></property>
+<property><name>mapred.job.shuffle.input.buffer.percent</name><value>0.70</value></property>
+<property><name>mapred.map.tasks.speculative.execution</name><value>true</value></property>
+<property><name>mapred.job.name</name><value>PageRank</value></property>
+<property><name>hadoop.util.hash.type</name><value>murmur</value></property>
 <property><name>mapred.map.max.attempts</name><value>4</value></property>
-<property><name>jobclient.output.filter</name><value>FAILED</value></property>
+<property><name>pregelix.incStateLength</name><value>false</value></property>
+<property><name>mapred.job.tracker.handler.count</name><value>10</value></property>
+<property><name>mapred.tasktracker.expiry.interval</name><value>600000</value></property>
+<property><name>mapred.jobtracker.maxtasks.per.job</name><value>-1</value></property>
+<property><name>mapred.jobtracker.job.history.block.size</name><value>3145728</value></property>
+<property><name>keep.failed.task.files</name><value>false</value></property>
 <property><name>ipc.client.tcpnodelay</name><value>false</value></property>
+<property><name>mapred.task.profile.reduces</name><value>0-2</value></property>
+<property><name>mapred.output.compression.codec</name><value>org.apache.hadoop.io.compress.DefaultCodec</value></property>
+<property><name>io.map.index.skip</name><value>0</value></property>
+<property><name>ipc.server.tcpnodelay</name><value>false</value></property>
+<property><name>hadoop.logfile.size</name><value>10000000</value></property>
+<property><name>mapred.reduce.tasks.speculative.execution</name><value>true</value></property>
+<property><name>fs.checkpoint.period</name><value>3600</value></property>
+<property><name>mapred.job.reuse.jvm.num.tasks</name><value>1</value></property>
+<property><name>mapred.jobtracker.completeuserjobs.maximum</name><value>100</value></property>
+<property><name>fs.s3.maxRetries</name><value>4</value></property>
+<property><name>mapred.local.dir</name><value>${hadoop.tmp.dir}/mapred/local</value></property>
+<property><name>fs.hftp.impl</name><value>org.apache.hadoop.hdfs.HftpFileSystem</value></property>
+<property><name>fs.trash.interval</name><value>0</value></property>
+<property><name>fs.s3.sleepTimeSeconds</name><value>10</value></property>
+<property><name>mapred.submit.replication</name><value>10</value></property>
+<property><name>fs.har.impl</name><value>org.apache.hadoop.fs.HarFileSystem</value></property>
+<property><name>mapred.map.output.compression.codec</name><value>org.apache.hadoop.io.compress.DefaultCodec</value></property>
+<property><name>mapred.tasktracker.dns.interface</name><value>default</value></property>
+<property><name>mapred.job.tracker</name><value>local</value></property>
+<property><name>io.seqfile.sorter.recordlimit</name><value>1000000</value></property>
+<property><name>mapred.line.input.format.linespermap</name><value>1</value></property>
+<property><name>mapred.jobtracker.taskScheduler</name><value>org.apache.hadoop.mapred.JobQueueTaskScheduler</value></property>
+<property><name>mapred.tasktracker.instrumentation</name><value>org.apache.hadoop.mapred.TaskTrackerMetricsInst</value></property>
+<property><name>mapred.tasktracker.procfsbasedprocesstree.sleeptime-before-sigkill</name><value>5000</value></property>
+<property><name>mapred.local.dir.minspacekill</name><value>0</value></property>
+<property><name>io.sort.record.percent</name><value>0.05</value></property>
+<property><name>fs.kfs.impl</name><value>org.apache.hadoop.fs.kfs.KosmosFileSystem</value></property>
+<property><name>mapred.temp.dir</name><value>${hadoop.tmp.dir}/mapred/temp</value></property>
+<property><name>mapred.tasktracker.reduce.tasks.maximum</name><value>2</value></property>
+<property><name>fs.checkpoint.edits.dir</name><value>${fs.checkpoint.dir}</value></property>
+<property><name>mapred.job.reduce.input.buffer.percent</name><value>0.0</value></property>
+<property><name>mapred.tasktracker.indexcache.mb</name><value>10</value></property>
+<property><name>pregelix.nmkComputerClass</name><value>edu.uci.ics.pregelix.example.data.VLongNormalizedKeyComputer</value></property>
+<property><name>hadoop.logfile.count</name><value>10</value></property>
+<property><name>mapred.skip.reduce.auto.incr.proc.count</name><value>true</value></property>
+<property><name>io.seqfile.compress.blocksize</name><value>1000000</value></property>
+<property><name>fs.s3.block.size</name><value>67108864</value></property>
+<property><name>mapred.tasktracker.taskmemorymanager.monitoring-interval</name><value>5000</value></property>
 <property><name>mapred.acls.enabled</name><value>false</value></property>
+<property><name>mapred.queue.names</name><value>default</value></property>
+<property><name>fs.hsftp.impl</name><value>org.apache.hadoop.hdfs.HsftpFileSystem</value></property>
+<property><name>mapred.task.tracker.http.address</name><value>0.0.0.0:50060</value></property>
+<property><name>pregelix.vertexClass</name><value>edu.uci.ics.pregelix.example.PageRankVertex</value></property>
+<property><name>mapred.reduce.parallel.copies</name><value>5</value></property>
+<property><name>io.seqfile.lazydecompress</name><value>true</value></property>
+<property><name>mapred.output.dir</name><value>/resultcomplex</value></property>
+<property><name>io.sort.mb</name><value>100</value></property>
+<property><name>ipc.client.connection.maxidletime</name><value>10000</value></property>
+<property><name>mapred.compress.map.output</name><value>false</value></property>
+<property><name>mapred.task.tracker.report.address</name><value>127.0.0.1:0</value></property>
+<property><name>ipc.client.kill.max</name><value>10</value></property>
+<property><name>ipc.client.connect.max.retries</name><value>10</value></property>
+<property><name>fs.s3.impl</name><value>org.apache.hadoop.fs.s3.S3FileSystem</value></property>
+<property><name>mapred.job.tracker.http.address</name><value>0.0.0.0:50030</value></property>
+<property><name>mapred.input.dir</name><value>file:/webmapcomplex</value></property>
+<property><name>io.file.buffer.size</name><value>4096</value></property>
+<property><name>mapred.jobtracker.restart.recover</name><value>false</value></property>
+<property><name>io.serializations</name><value>org.apache.hadoop.io.serializer.WritableSerialization</value></property>
+<property><name>pregelix.vertexInputFormatClass</name><value>edu.uci.ics.pregelix.example.inputformat.TextPageRankInputFormat</value></property>
+<property><name>mapred.reduce.copy.backoff</name><value>300</value></property>
+<property><name>pregelix.vertexOutputFormatClass</name><value>edu.uci.ics.pregelix.example.PageRankVertex$SimplePageRankVertexOutputFormat</value></property>
+<property><name>mapred.task.profile</name><value>false</value></property>
+<property><name>jobclient.output.filter</name><value>FAILED</value></property>
+<property><name>mapred.tasktracker.map.tasks.maximum</name><value>2</value></property>
+<property><name>io.compression.codecs</name><value>org.apache.hadoop.io.compress.DefaultCodec,org.apache.hadoop.io.compress.GzipCodec,org.apache.hadoop.io.compress.BZip2Codec</value></property>
+<property><name>fs.checkpoint.size</name><value>67108864</value></property>
 </configuration>
\ No newline at end of file
diff --git a/pregelix/pregelix-example/src/test/resources/jobs/PageRankRealNoCombiner.xml b/pregelix/pregelix-example/src/test/resources/jobs/PageRankRealNoCombiner.xml
index 636b055..8969fd7 100644
--- a/pregelix/pregelix-example/src/test/resources/jobs/PageRankRealNoCombiner.xml
+++ b/pregelix/pregelix-example/src/test/resources/jobs/PageRankRealNoCombiner.xml
@@ -127,6 +127,7 @@
 <property><name>pregelix.vertexInputFormatClass</name><value>edu.uci.ics.pregelix.example.inputformat.TextPageRankInputFormat</value></property>
 <property><name>mapred.job.queue.name</name><value>default</value></property>
 <property><name>mapred.job.tracker.persist.jobstatus.active</name><value>false</value></property>
+<property><name>pregelix.incStateLength</name><value>false</value></property>
 <property><name>mapred.reduce.slowstart.completed.maps</name><value>0.05</value></property>
 <property><name>topology.script.number.args</name><value>100</value></property>
 <property><name>mapred.skip.map.max.skip.records</name><value>0</value></property>
diff --git a/pregelix/pregelix-runtime/pom.xml b/pregelix/pregelix-runtime/pom.xml
index 6564eb0..245c0f5 100644
--- a/pregelix/pregelix-runtime/pom.xml
+++ b/pregelix/pregelix-runtime/pom.xml
@@ -141,6 +141,13 @@
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
+			<artifactId>hyracks-storage-common</artifactId>
+			<version>0.2.10-SNAPSHOT</version>
+			<type>jar</type>
+			<scope>compile</scope>
+		</dependency>
+		<dependency>
+			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-storage-am-btree</artifactId>
 			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
diff --git a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/function/ComputeUpdateFunctionFactory.java b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/function/ComputeUpdateFunctionFactory.java
index f3a0bb4..a002be0 100644
--- a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/function/ComputeUpdateFunctionFactory.java
+++ b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/function/ComputeUpdateFunctionFactory.java
@@ -31,6 +31,8 @@
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.FrameTupleAppender;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
+import edu.uci.ics.hyracks.storage.am.common.api.IIndexCursor;
+import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexCursor;
 import edu.uci.ics.pregelix.api.graph.GlobalAggregator;
 import edu.uci.ics.pregelix.api.graph.MsgList;
 import edu.uci.ics.pregelix.api.graph.Vertex;
@@ -110,7 +112,8 @@
             public void open(IHyracksTaskContext ctx, RecordDescriptor rd, IFrameWriter... writers)
                     throws HyracksDataException {
                 this.conf = confFactory.createConfiguration(ctx);
-                this.dynamicStateLength = BspUtils.getDynamicVertexValueSize(conf);
+                //LSM index does not have in-place update
+                this.dynamicStateLength = BspUtils.getDynamicVertexValueSize(conf) || BspUtils.useLSM(conf);
                 this.aggregator = BspUtils.createGlobalAggregator(conf);
                 this.aggregator.init();
 
@@ -197,6 +200,10 @@
                     }
                     vertex.finishCompute();
                 } catch (Exception e) {
+                    ClassLoader cl1 = vertex.getClass().getClassLoader();
+                    ClassLoader cl2 = msgContentList.get(0).getClass().getClassLoader();
+                    System.out.println("cl1 " + cl1);
+                    System.out.println("cl2 " + cl2);
                     throw new HyracksDataException(e);
                 }
 
@@ -262,7 +269,8 @@
             }
 
             @Override
-            public void update(ITupleReference tupleRef, ArrayTupleBuilder cloneUpdateTb) throws HyracksDataException {
+            public void update(ITupleReference tupleRef, ArrayTupleBuilder cloneUpdateTb, IIndexCursor cursor)
+                    throws HyracksDataException {
                 try {
                     if (vertex != null && vertex.hasUpdate()) {
                         if (!dynamicStateLength) {
@@ -271,12 +279,13 @@
                             int offset = tupleRef.getFieldStart(1);
                             bbos.setByteArray(data, offset);
                             vertex.write(output);
+                            ITreeIndexCursor tCursor = (ITreeIndexCursor) cursor;
+                            tCursor.markCurrentTupleAsUpdated();
                         } else {
                             // write the vertex id
                             DataOutput tbOutput = cloneUpdateTb.getDataOutput();
                             vertex.getVertexId().write(tbOutput);
                             cloneUpdateTb.addFieldEndOffset();
-
                             // write the vertex value
                             vertex.write(tbOutput);
                             cloneUpdateTb.addFieldEndOffset();
diff --git a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/function/NoOpUpdateFunctionFactory.java b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/function/NoOpUpdateFunctionFactory.java
index 88577c2..8947c01 100644
--- a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/function/NoOpUpdateFunctionFactory.java
+++ b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/function/NoOpUpdateFunctionFactory.java
@@ -20,6 +20,7 @@
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
+import edu.uci.ics.hyracks.storage.am.common.api.IIndexCursor;
 import edu.uci.ics.pregelix.dataflow.std.base.IUpdateFunction;
 import edu.uci.ics.pregelix.dataflow.std.base.IUpdateFunctionFactory;
 
@@ -57,7 +58,8 @@
             }
 
             @Override
-            public void update(ITupleReference tupleRef, ArrayTupleBuilder cloneUpdateTb) throws HyracksDataException {
+            public void update(ITupleReference tupleRef, ArrayTupleBuilder cloneUpdateTb, IIndexCursor cursor)
+                    throws HyracksDataException {
 
             }
 
diff --git a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/function/StartComputeUpdateFunctionFactory.java b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/function/StartComputeUpdateFunctionFactory.java
index ca8ec01..1d26c83 100644
--- a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/function/StartComputeUpdateFunctionFactory.java
+++ b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/function/StartComputeUpdateFunctionFactory.java
@@ -31,6 +31,8 @@
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.FrameTupleAppender;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
+import edu.uci.ics.hyracks.storage.am.common.api.IIndexCursor;
+import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexCursor;
 import edu.uci.ics.pregelix.api.graph.GlobalAggregator;
 import edu.uci.ics.pregelix.api.graph.MsgList;
 import edu.uci.ics.pregelix.api.graph.Vertex;
@@ -113,7 +115,8 @@
             public void open(IHyracksTaskContext ctx, RecordDescriptor rd, IFrameWriter... writers)
                     throws HyracksDataException {
                 this.conf = confFactory.createConfiguration(ctx);
-                this.dynamicStateLength = BspUtils.getDynamicVertexValueSize(conf);
+                //LSM index does not have in-place update
+                this.dynamicStateLength = BspUtils.getDynamicVertexValueSize(conf) || BspUtils.useLSM(conf);;
                 this.aggregator = BspUtils.createGlobalAggregator(conf);
                 this.aggregator.init();
 
@@ -255,7 +258,8 @@
             }
 
             @Override
-            public void update(ITupleReference tupleRef, ArrayTupleBuilder cloneUpdateTb) throws HyracksDataException {
+            public void update(ITupleReference tupleRef, ArrayTupleBuilder cloneUpdateTb, IIndexCursor cursor)
+                    throws HyracksDataException {
                 try {
                     if (vertex != null && vertex.hasUpdate()) {
                         if (!dynamicStateLength) {
@@ -264,6 +268,8 @@
                             int offset = tupleRef.getFieldStart(1);
                             bbos.setByteArray(data, offset);
                             vertex.write(output);
+                            ITreeIndexCursor tCursor = (ITreeIndexCursor) cursor;
+                            tCursor.markCurrentTupleAsUpdated();
                         } else {
                             // write the vertex id
                             DataOutput tbOutput = cloneUpdateTb.getDataOutput();
diff --git a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AccumulatingAggregatorFactory.java b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AccumulatingAggregatorFactory.java
index acd766e..d243c8a 100644
--- a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AccumulatingAggregatorFactory.java
+++ b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AccumulatingAggregatorFactory.java
@@ -99,7 +99,7 @@
             }
 
             @Override
-            public void outputFinalResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
+            public boolean outputFinalResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
                     AggregateState state) throws HyracksDataException {
                 Pair<ArrayBackedValueStorage[], IAggregateFunction[]> aggState = (Pair<ArrayBackedValueStorage[], IAggregateFunction[]>) state.state;
                 ArrayBackedValueStorage[] aggOutput = aggState.getLeft();
@@ -113,6 +113,7 @@
                         throw new HyracksDataException(e);
                     }
                 }
+                return true;
             }
 
             @Override
@@ -121,7 +122,7 @@
             }
 
             @Override
-            public void outputPartialResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
+            public boolean outputPartialResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
                     AggregateState state) throws HyracksDataException {
                 throw new IllegalStateException("this method should not be called");
             }
diff --git a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/DatatypeHelper.java b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/DatatypeHelper.java
index b121b5b..e99fcb3 100644
--- a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/DatatypeHelper.java
+++ b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/DatatypeHelper.java
@@ -17,32 +17,30 @@
 import java.io.DataInput;
 import java.io.DataOutput;
 import java.io.IOException;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Map.Entry;
 
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.io.NullWritable;
 import org.apache.hadoop.io.Writable;
-import org.apache.hadoop.mapred.JobConf;
 
 import edu.uci.ics.hyracks.api.dataflow.value.ISerializerDeserializer;
 import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+import edu.uci.ics.pregelix.api.util.ArrayListWritable;
 
-@SuppressWarnings("deprecation")
 public class DatatypeHelper {
     private static final class WritableSerializerDeserializer<T extends Writable> implements ISerializerDeserializer<T> {
         private static final long serialVersionUID = 1L;
 
-        private Class<T> clazz;
+        private final Class<T> clazz;
+        private transient Configuration conf;
         private T object;
 
-        private WritableSerializerDeserializer(Class<T> clazz) {
+        private WritableSerializerDeserializer(Class<T> clazz, Configuration conf) {
             this.clazz = clazz;
+            this.conf = conf;
         }
 
-        @SuppressWarnings("unchecked")
+        @SuppressWarnings({ "unchecked", "rawtypes" })
         private T createInstance() throws HyracksDataException {
             // TODO remove "if", create a new WritableInstanceOperations class
             // that deals with Writables that don't have public constructors
@@ -50,7 +48,11 @@
                 return (T) NullWritable.get();
             }
             try {
-                return clazz.newInstance();
+                T t = clazz.newInstance();
+                if (t instanceof ArrayListWritable) {
+                    ((ArrayListWritable) t).setConf(conf);
+                }
+                return t;
             } catch (InstantiationException e) {
                 throw new HyracksDataException(e);
             } catch (IllegalAccessException e) {
@@ -85,42 +87,16 @@
 
     @SuppressWarnings({ "rawtypes", "unchecked" })
     public static ISerializerDeserializer<? extends Writable> createSerializerDeserializer(
-            Class<? extends Writable> fClass) {
-        return new WritableSerializerDeserializer(fClass);
+            Class<? extends Writable> fClass, Configuration conf) {
+        return new WritableSerializerDeserializer(fClass, conf);
     }
 
     public static RecordDescriptor createKeyValueRecordDescriptor(Class<? extends Writable> keyClass,
-            Class<? extends Writable> valueClass) {
+            Class<? extends Writable> valueClass, Configuration conf) {
         @SuppressWarnings("rawtypes")
         ISerializerDeserializer[] fields = new ISerializerDeserializer[2];
-        fields[0] = createSerializerDeserializer(keyClass);
-        fields[1] = createSerializerDeserializer(valueClass);
+        fields[0] = createSerializerDeserializer(keyClass, conf);
+        fields[1] = createSerializerDeserializer(valueClass, conf);
         return new RecordDescriptor(fields);
     }
-
-    public static RecordDescriptor createOneFieldRecordDescriptor(Class<? extends Writable> fieldClass) {
-        @SuppressWarnings("rawtypes")
-        ISerializerDeserializer[] fields = new ISerializerDeserializer[1];
-        fields[0] = createSerializerDeserializer(fieldClass);
-        return new RecordDescriptor(fields);
-    }
-
-    public static JobConf map2JobConf(Map<String, String> jobConfMap) {
-        JobConf jobConf;
-        synchronized (Configuration.class) {
-            jobConf = new JobConf();
-            for (Entry<String, String> entry : jobConfMap.entrySet()) {
-                jobConf.set(entry.getKey(), entry.getValue());
-            }
-        }
-        return jobConf;
-    }
-
-    public static Map<String, String> jobConf2Map(JobConf jobConf) {
-        Map<String, String> jobConfMap = new HashMap<String, String>();
-        for (Entry<String, String> entry : jobConf) {
-            jobConfMap.put(entry.getKey(), entry.getValue());
-        }
-        return jobConfMap;
-    }
 }
\ No newline at end of file
diff --git a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/RuntimeHookFactory.java b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/RuntimeHookFactory.java
index 5e8ac1e..3151df2 100644
--- a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/RuntimeHookFactory.java
+++ b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/RuntimeHookFactory.java
@@ -14,6 +14,8 @@
  */
 package edu.uci.ics.pregelix.runtime.touchpoint;
 
+import java.lang.reflect.Field;
+
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.mapreduce.TaskAttemptContext;
 import org.apache.hadoop.mapreduce.TaskAttemptID;
@@ -21,8 +23,6 @@
 import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.hdfs.ContextFactory;
-import edu.uci.ics.pregelix.api.graph.Vertex;
-import edu.uci.ics.pregelix.api.util.BspUtils;
 import edu.uci.ics.pregelix.dataflow.base.IConfigurationFactory;
 import edu.uci.ics.pregelix.dataflow.std.base.IRuntimeHook;
 import edu.uci.ics.pregelix.dataflow.std.base.IRuntimeHookFactory;
@@ -48,8 +48,12 @@
                 try {
                     TaskAttemptContext mapperContext = ctxFactory.createContext(conf, new TaskAttemptID());
                     mapperContext.getConfiguration().setClassLoader(ctx.getJobletContext().getClassLoader());
-                    Vertex.setContext(mapperContext);
-                    BspUtils.setDefaultConfiguration(conf);
+
+                    ClassLoader cl = ctx.getJobletContext().getClassLoader();
+                    Class<?> vClass = (Class<?>) cl.loadClass("edu.uci.ics.pregelix.api.graph.Vertex");
+                    Field contextField = vClass.getDeclaredField("context");
+                    contextField.setAccessible(true);
+                    contextField.set(null, mapperContext);
                 } catch (Exception e) {
                     throw new HyracksDataException(e);
                 }
diff --git a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/VertexIdPartitionComputerFactory.java b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/VertexIdPartitionComputerFactory.java
index 6fa6434..c9b67fb 100644
--- a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/VertexIdPartitionComputerFactory.java
+++ b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/VertexIdPartitionComputerFactory.java
@@ -16,6 +16,7 @@
 
 import java.io.DataInputStream;
 
+import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.io.Writable;
 
 import edu.uci.ics.hyracks.api.comm.IFrameTupleAccessor;
@@ -24,30 +25,39 @@
 import edu.uci.ics.hyracks.api.dataflow.value.ITuplePartitionComputerFactory;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.dataflow.common.comm.util.ByteBufferInputStream;
+import edu.uci.ics.pregelix.dataflow.base.IConfigurationFactory;
 import edu.uci.ics.pregelix.dataflow.std.base.ISerializerDeserializerFactory;
 
 public class VertexIdPartitionComputerFactory<K extends Writable, V extends Writable> implements
         ITuplePartitionComputerFactory {
     private static final long serialVersionUID = 1L;
     private final ISerializerDeserializerFactory<K> keyIOFactory;
+    private final IConfigurationFactory confFactory;
 
-    public VertexIdPartitionComputerFactory(ISerializerDeserializerFactory<K> keyIOFactory) {
+    public VertexIdPartitionComputerFactory(ISerializerDeserializerFactory<K> keyIOFactory,
+            IConfigurationFactory confFactory) {
         this.keyIOFactory = keyIOFactory;
+        this.confFactory = confFactory;
     }
 
     public ITuplePartitionComputer createPartitioner() {
-        return new ITuplePartitionComputer() {
-            private final ByteBufferInputStream bbis = new ByteBufferInputStream();
-            private final DataInputStream dis = new DataInputStream(bbis);
-            private final ISerializerDeserializer<K> keyIO = keyIOFactory.getSerializerDeserializer();
+        try {
+            final Configuration conf = confFactory.createConfiguration();
+            return new ITuplePartitionComputer() {
+                private final ByteBufferInputStream bbis = new ByteBufferInputStream();
+                private final DataInputStream dis = new DataInputStream(bbis);
+                private final ISerializerDeserializer<K> keyIO = keyIOFactory.getSerializerDeserializer(conf);
 
-            public int partition(IFrameTupleAccessor accessor, int tIndex, int nParts) throws HyracksDataException {
-                int keyStart = accessor.getTupleStartOffset(tIndex) + accessor.getFieldSlotsLength()
-                        + accessor.getFieldStartOffset(tIndex, 0);
-                bbis.setByteBuffer(accessor.getBuffer(), keyStart);
-                K key = keyIO.deserialize(dis);
-                return Math.abs(key.hashCode() % nParts);
-            }
-        };
+                public int partition(IFrameTupleAccessor accessor, int tIndex, int nParts) throws HyracksDataException {
+                    int keyStart = accessor.getTupleStartOffset(tIndex) + accessor.getFieldSlotsLength()
+                            + accessor.getFieldStartOffset(tIndex, 0);
+                    bbis.setByteBuffer(accessor.getBuffer(), keyStart);
+                    K key = keyIO.deserialize(dis);
+                    return Math.abs(key.hashCode() % nParts);
+                }
+            };
+        } catch (Exception e) {
+            throw new IllegalStateException(e);
+        }
     }
 }
\ No newline at end of file
diff --git a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/WritableSerializerDeserializerFactory.java b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/WritableSerializerDeserializerFactory.java
index 435d081..c11ac5b 100644
--- a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/WritableSerializerDeserializerFactory.java
+++ b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/WritableSerializerDeserializerFactory.java
@@ -14,6 +14,7 @@
  */
 package edu.uci.ics.pregelix.runtime.touchpoint;
 
+import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.io.Writable;
 
 import edu.uci.ics.hyracks.api.dataflow.value.ISerializerDeserializer;
@@ -29,7 +30,7 @@
 
     @SuppressWarnings({ "rawtypes", "unchecked" })
     @Override
-    public ISerializerDeserializer getSerializerDeserializer() {
-        return DatatypeHelper.createSerializerDeserializer(clazz);
+    public ISerializerDeserializer getSerializerDeserializer(Configuration conf) {
+        return DatatypeHelper.createSerializerDeserializer(clazz, conf);
     }
 }