diff --git a/.gitignore b/.gitignore
index a9010ba..0517ac2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,6 +12,8 @@
 teststore2
 dev1
 dev2
+dev3
+dev4
 derby.log
 hadoop-conf-tmp
 metastore_db
diff --git a/algebricks/algebricks-common/pom.xml b/algebricks/algebricks-common/pom.xml
index 969931b..a6279b9 100644
--- a/algebricks/algebricks-common/pom.xml
+++ b/algebricks/algebricks-common/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>algebricks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -41,7 +41,7 @@
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>hyracks-api</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   </dependencies>
 </project>
diff --git a/algebricks/algebricks-compiler/pom.xml b/algebricks/algebricks-compiler/pom.xml
index 08f9bfe..f276439 100644
--- a/algebricks/algebricks-compiler/pom.xml
+++ b/algebricks/algebricks-compiler/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>algebricks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -41,12 +41,12 @@
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>algebricks-rewriter</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>algebricks-core</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   </dependencies>
 </project>
diff --git a/algebricks/algebricks-core/pom.xml b/algebricks/algebricks-core/pom.xml
index 9a1bd0a..ac8cd89 100644
--- a/algebricks/algebricks-core/pom.xml
+++ b/algebricks/algebricks-core/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>algebricks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -41,27 +41,27 @@
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>hyracks-storage-am-btree</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>hyracks-storage-am-rtree</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>hyracks-dataflow-std</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>algebricks-runtime</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>algebricks-common</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   </dependencies>
 </project>
diff --git a/algebricks/algebricks-data/pom.xml b/algebricks/algebricks-data/pom.xml
index b5918d5..b61a701 100644
--- a/algebricks/algebricks-data/pom.xml
+++ b/algebricks/algebricks-data/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>algebricks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -41,12 +41,12 @@
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>algebricks-common</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>hyracks-data-std</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   </dependencies>
 </project>
diff --git a/algebricks/algebricks-examples/piglet-example/pom.xml b/algebricks/algebricks-examples/piglet-example/pom.xml
index f984625..8297f4d 100644
--- a/algebricks/algebricks-examples/piglet-example/pom.xml
+++ b/algebricks/algebricks-examples/piglet-example/pom.xml
@@ -20,7 +20,7 @@
 	<parent>
 		<groupId>edu.uci.ics.hyracks</groupId>
 		<artifactId>algebricks-examples</artifactId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 	</parent>
 
 	<build>
@@ -121,7 +121,7 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>algebricks-compiler</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 		</dependency>
 		<dependency>
 			<groupId>junit</groupId>
diff --git a/algebricks/algebricks-examples/pom.xml b/algebricks/algebricks-examples/pom.xml
index abb0747..31b7f2c 100644
--- a/algebricks/algebricks-examples/pom.xml
+++ b/algebricks/algebricks-examples/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>algebricks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <modules>
diff --git a/algebricks/algebricks-rewriter/pom.xml b/algebricks/algebricks-rewriter/pom.xml
index 8c936ea..e66486f 100644
--- a/algebricks/algebricks-rewriter/pom.xml
+++ b/algebricks/algebricks-rewriter/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>algebricks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -41,7 +41,7 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>algebricks-core</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   	</dependency>
   </dependencies>
 </project>
diff --git a/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/EliminateGroupByEmptyKeyRule.java b/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/EliminateGroupByEmptyKeyRule.java
new file mode 100644
index 0000000..e93fdd1
--- /dev/null
+++ b/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/EliminateGroupByEmptyKeyRule.java
@@ -0,0 +1,86 @@
+/*
+ * 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.rewriter.rules;
+
+import java.util.List;
+
+import org.apache.commons.lang3.mutable.Mutable;
+
+import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalPlan;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.IOptimizationContext;
+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.operators.logical.AbstractLogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.GroupByOperator;
+import edu.uci.ics.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule;
+
+/**
+ * This rule lift out the aggregate operator out from a group-by operator
+ * if the gby operator groups-by on empty key, e.g., the group-by variables are empty.
+ * 
+ * @author yingyib
+ */
+public class EliminateGroupByEmptyKeyRule implements IAlgebraicRewriteRule {
+
+    @Override
+    public boolean rewritePre(Mutable<ILogicalOperator> opRef, IOptimizationContext context) throws AlgebricksException {
+        return false;
+    }
+
+    @Override
+    public boolean rewritePost(Mutable<ILogicalOperator> opRef, IOptimizationContext context)
+            throws AlgebricksException {
+        AbstractLogicalOperator op = (AbstractLogicalOperator) opRef.getValue();
+        if (op.getOperatorTag() != LogicalOperatorTag.GROUP) {
+            return false;
+        }
+        GroupByOperator groupOp = (GroupByOperator) op;
+        List<LogicalVariable> groupVars = groupOp.getGbyVarList();
+        if (groupVars.size() > 0) {
+            return false;
+        }
+        List<ILogicalPlan> nestedPlans = groupOp.getNestedPlans();
+        if (nestedPlans.size() > 1) {
+            return false;
+        }
+        ILogicalPlan nestedPlan = nestedPlans.get(0);
+        if (nestedPlan.getRoots().size() > 1) {
+            return false;
+        }
+        Mutable<ILogicalOperator> topOpRef = nestedPlan.getRoots().get(0);
+        ILogicalOperator topOp = nestedPlan.getRoots().get(0).getValue();
+        Mutable<ILogicalOperator> nestedTupleSourceRef = getNestedTupleSourceReference(topOpRef);
+        /**
+         * connect nested top op into the plan
+         */
+        opRef.setValue(topOp);
+        /**
+         * connect child op into the plan
+         */
+        nestedTupleSourceRef.setValue(groupOp.getInputs().get(0).getValue());
+        return true;
+    }
+
+    private Mutable<ILogicalOperator> getNestedTupleSourceReference(Mutable<ILogicalOperator> nestedTopOperatorRef) {
+        Mutable<ILogicalOperator> currentOpRef = nestedTopOperatorRef;
+        while (currentOpRef.getValue().getInputs() != null && currentOpRef.getValue().getInputs().size() > 0) {
+            currentOpRef = currentOpRef.getValue().getInputs().get(0);
+        }
+        return currentOpRef;
+    }
+
+}
diff --git a/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/LeftOuterJoinToInnerJoinRule.java b/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/LeftOuterJoinToInnerJoinRule.java
new file mode 100644
index 0000000..247c10d
--- /dev/null
+++ b/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/LeftOuterJoinToInnerJoinRule.java
@@ -0,0 +1,118 @@
+/*
+ * 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.rewriter.rules;
+
+import org.apache.commons.lang3.mutable.Mutable;
+
+import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
+import edu.uci.ics.hyracks.algebricks.common.utils.ListSet;
+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.IOptimizationContext;
+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.expressions.ScalarFunctionCallExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.VariableReferenceExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.functions.AlgebricksBuiltinFunctions;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.AbstractLogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.InnerJoinOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.LeftOuterJoinOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.SelectOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.visitors.VariableUtilities;
+import edu.uci.ics.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule;
+
+/**
+ * This rule is to convert an outer join into an inner join when possible.
+ * 
+ * The specific pattern this rule will invoke for is:
+ * select not(is-null($v)) // $v is from the right branch of the left outer join below
+ *   left-outer-join
+ * 
+ * The pattern will be rewritten to:
+ * inner-join
+ * 
+ * @author yingyib
+ */
+public class LeftOuterJoinToInnerJoinRule implements IAlgebraicRewriteRule {
+
+    @Override
+    public boolean rewritePre(Mutable<ILogicalOperator> opRef, IOptimizationContext context) throws AlgebricksException {
+        return false;
+    }
+
+    @Override
+    public boolean rewritePost(Mutable<ILogicalOperator> opRef, IOptimizationContext context)
+            throws AlgebricksException {
+        AbstractLogicalOperator op = (AbstractLogicalOperator) opRef.getValue();
+        if (op.getOperatorTag() != LogicalOperatorTag.SELECT) {
+            return false;
+        }
+        Mutable<ILogicalOperator> op2Ref = op.getInputs().get(0);
+        AbstractLogicalOperator op2 = (AbstractLogicalOperator) op2Ref.getValue();
+        if (op2.getOperatorTag() != LogicalOperatorTag.LEFTOUTERJOIN) {
+            return false;
+        }
+        SelectOperator selectOp = (SelectOperator) op;
+        LeftOuterJoinOperator joinOp = (LeftOuterJoinOperator) op2;
+        ILogicalExpression condition = selectOp.getCondition().getValue();
+        if (condition.getExpressionTag() != LogicalExpressionTag.FUNCTION_CALL) {
+            return false;
+        }
+        ScalarFunctionCallExpression func = (ScalarFunctionCallExpression) condition;
+        /** check if the filter condition on top of the LOJ is not(is-null($v)), where $v is from the right child of LOJ */
+        if (!convertable(func, joinOp)) {
+            return false;
+        }
+        ILogicalOperator newJoin = new InnerJoinOperator(joinOp.getCondition(), joinOp.getInputs().get(0), joinOp
+                .getInputs().get(1));
+        opRef.setValue(newJoin);
+        context.computeAndSetTypeEnvironmentForOperator(newJoin);
+        return true;
+    }
+
+    /**
+     * check if the condition is not(is-null(var)) and var is from the right branch of the join
+     */
+    private boolean convertable(ScalarFunctionCallExpression func, LeftOuterJoinOperator join)
+            throws AlgebricksException {
+        if (func.getFunctionIdentifier() != AlgebricksBuiltinFunctions.NOT) {
+            return false;
+        }
+        ILogicalExpression arg = func.getArguments().get(0).getValue();
+        if (arg.getExpressionTag() != LogicalExpressionTag.FUNCTION_CALL) {
+            return false;
+        }
+        ScalarFunctionCallExpression func2 = (ScalarFunctionCallExpression) arg;
+        if (func2.getFunctionIdentifier() != AlgebricksBuiltinFunctions.IS_NULL) {
+            return false;
+        }
+        ILogicalExpression arg2 = func2.getArguments().get(0).getValue();
+        if (arg2.getExpressionTag() != LogicalExpressionTag.VARIABLE) {
+            return false;
+        }
+        VariableReferenceExpression varExpr = (VariableReferenceExpression) arg2;
+        LogicalVariable var = varExpr.getVariableReference();
+        ListSet<LogicalVariable> leftVars = new ListSet<LogicalVariable>();
+        ListSet<LogicalVariable> rightVars = new ListSet<LogicalVariable>();
+        VariableUtilities.getLiveVariables(join.getInputs().get(0).getValue(), leftVars);
+        VariableUtilities.getLiveVariables(join.getInputs().get(1).getValue(), rightVars);
+        if (!rightVars.contains(var)) {
+            return false;
+        }
+        return true;
+    }
+
+}
diff --git a/algebricks/algebricks-runtime/pom.xml b/algebricks/algebricks-runtime/pom.xml
index 835b255..570afb4 100644
--- a/algebricks/algebricks-runtime/pom.xml
+++ b/algebricks/algebricks-runtime/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>algebricks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -41,27 +41,27 @@
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>hyracks-storage-am-btree</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>hyracks-storage-am-rtree</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>hyracks-dataflow-std</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>algebricks-common</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>algebricks-data</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   </dependencies>
 </project>
diff --git a/algebricks/algebricks-tests/pom.xml b/algebricks/algebricks-tests/pom.xml
index e687637..4d7abad 100644
--- a/algebricks/algebricks-tests/pom.xml
+++ b/algebricks/algebricks-tests/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>algebricks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -99,7 +99,7 @@
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>algebricks-compiler</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   <dependency>
   	<groupId>junit</groupId>
@@ -110,17 +110,17 @@
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>hyracks-control-cc</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>hyracks-control-nc</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>hyracks-data-std</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   </dependencies>
 </project>
diff --git a/algebricks/pom.xml b/algebricks/pom.xml
index 16ca5c8..427e29b 100644
--- a/algebricks/pom.xml
+++ b/algebricks/pom.xml
@@ -16,7 +16,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>edu.uci.ics.hyracks</groupId>
   <artifactId>algebricks</artifactId>
-  <version>0.2.9-SNAPSHOT</version>
+  <version>0.2.10-SNAPSHOT</version>
   <packaging>pom</packaging>
   <name>algebricks</name>
 
diff --git a/hivesterix/hivesterix-common/pom.xml b/hivesterix/hivesterix-common/pom.xml
index 5b0c8bb..fe9271b 100644
--- a/hivesterix/hivesterix-common/pom.xml
+++ b/hivesterix/hivesterix-common/pom.xml
@@ -16,7 +16,7 @@
 	<parent>
 		<artifactId>hivesterix</artifactId>
 		<groupId>edu.uci.ics.hyracks</groupId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 	</parent>
 
 	<build>
@@ -39,21 +39,21 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-api</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>algebricks-compiler</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-hdfs-core</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
@@ -67,7 +67,7 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hivesterix-serde</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
diff --git a/hivesterix/hivesterix-dist/pom.xml b/hivesterix/hivesterix-dist/pom.xml
index f041640..917487f 100644
--- a/hivesterix/hivesterix-dist/pom.xml
+++ b/hivesterix/hivesterix-dist/pom.xml
@@ -15,7 +15,7 @@
 	<parent>
 		<groupId>edu.uci.ics.hyracks</groupId>
 		<artifactId>hivesterix</artifactId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 	</parent>
 
 	<dependencies>
@@ -29,35 +29,35 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hivesterix-translator</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hivesterix-optimizer</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>algebricks-compiler</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-control-cc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-control-nc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
diff --git a/hivesterix/hivesterix-optimizer/pom.xml b/hivesterix/hivesterix-optimizer/pom.xml
index 450d45d..858507e 100644
--- a/hivesterix/hivesterix-optimizer/pom.xml
+++ b/hivesterix/hivesterix-optimizer/pom.xml
@@ -18,7 +18,7 @@
 	<parent>
 		<artifactId>hivesterix</artifactId>
 		<groupId>edu.uci.ics.hyracks</groupId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 	</parent>
 
 	<artifactId>hivesterix-optimizer</artifactId>
@@ -44,14 +44,14 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hivesterix-common</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hivesterix-translator</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
diff --git a/hivesterix/hivesterix-runtime/pom.xml b/hivesterix/hivesterix-runtime/pom.xml
index edd7915..6d10286 100644
--- a/hivesterix/hivesterix-runtime/pom.xml
+++ b/hivesterix/hivesterix-runtime/pom.xml
@@ -20,7 +20,7 @@
 	<parent>
                 <groupId>edu.uci.ics.hyracks</groupId>
                 <artifactId>hivesterix</artifactId>
-                <version>0.2.9-SNAPSHOT</version>
+                <version>0.2.10-SNAPSHOT</version>
         </parent>
 
 	<dependencies>
@@ -106,35 +106,35 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>algebricks-compiler</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-control-cc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-control-nc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hivesterix-serde</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hivesterix-common</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
diff --git a/hivesterix/hivesterix-serde/pom.xml b/hivesterix/hivesterix-serde/pom.xml
index 3688058..b53661b 100644
--- a/hivesterix/hivesterix-serde/pom.xml
+++ b/hivesterix/hivesterix-serde/pom.xml
@@ -18,7 +18,7 @@
 	<parent>
 		<artifactId>hivesterix</artifactId>
 		<groupId>edu.uci.ics.hyracks</groupId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 	</parent>
 
 	<artifactId>hivesterix-serde</artifactId>
@@ -58,14 +58,14 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>algebricks-compiler</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-hdfs-core</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
diff --git a/hivesterix/hivesterix-translator/pom.xml b/hivesterix/hivesterix-translator/pom.xml
index fdd47b8..d8c205f 100644
--- a/hivesterix/hivesterix-translator/pom.xml
+++ b/hivesterix/hivesterix-translator/pom.xml
@@ -21,7 +21,7 @@
 	<parent>
 		<artifactId>hivesterix</artifactId>
 		<groupId>edu.uci.ics.hyracks</groupId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 	</parent>
 
 	<build>
@@ -44,21 +44,21 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>algebricks-compiler</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hivesterix-common</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hivesterix-runtime</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
diff --git a/hivesterix/pom.xml b/hivesterix/pom.xml
index 60c4736..ba43c0d 100644
--- a/hivesterix/pom.xml
+++ b/hivesterix/pom.xml
@@ -17,7 +17,7 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>edu.uci.ics.hyracks</groupId>
 	<artifactId>hivesterix</artifactId>
-	<version>0.2.9-SNAPSHOT</version>
+	<version>0.2.10-SNAPSHOT</version>
 	<packaging>pom</packaging>
 	<name>hivesterix</name>
 
diff --git a/hyracks/hyracks-api/pom.xml b/hyracks/hyracks-api/pom.xml
index 818cbce..6a56532 100644
--- a/hyracks/hyracks-api/pom.xml
+++ b/hyracks/hyracks-api/pom.xml
@@ -19,7 +19,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -61,7 +61,7 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-ipc</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   	</dependency>
   	<dependency>
   		<groupId>org.apache.commons</groupId>
diff --git a/hyracks/hyracks-client/pom.xml b/hyracks/hyracks-client/pom.xml
index 4c6897b..99ee616 100644
--- a/hyracks/hyracks-client/pom.xml
+++ b/hyracks/hyracks-client/pom.xml
@@ -19,7 +19,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -39,22 +39,22 @@
  <dependency>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-api</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
  </dependency>
  <dependency>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-net</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
  </dependency>
  <dependency>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-comm</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
  </dependency>
   <dependency>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-dataflow-common</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
  </dependency>
   </dependencies>
 </project>
diff --git a/hyracks/hyracks-comm/pom.xml b/hyracks/hyracks-comm/pom.xml
index 3b9aab2..f46971a 100644
--- a/hyracks/hyracks-comm/pom.xml
+++ b/hyracks/hyracks-comm/pom.xml
@@ -19,7 +19,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -39,12 +39,12 @@
  <dependency>
  	<groupId>edu.uci.ics.hyracks</groupId>
  	<artifactId>hyracks-api</artifactId>
- 	<version>0.2.9-SNAPSHOT</version>
+ 	<version>0.2.10-SNAPSHOT</version>
  </dependency>
   <dependency>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-net</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
  </dependency>
   </dependencies>
 </project>
diff --git a/hyracks/hyracks-control/hyracks-control-cc/pom.xml b/hyracks/hyracks-control/hyracks-control-cc/pom.xml
index e1c539b..17638e8 100644
--- a/hyracks/hyracks-control/hyracks-control-cc/pom.xml
+++ b/hyracks/hyracks-control/hyracks-control-cc/pom.xml
@@ -19,7 +19,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-control</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -40,7 +40,7 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-control-common</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
diff --git a/hyracks/hyracks-control/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/job/ExceptionFilterUtils.java b/hyracks/hyracks-control/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/job/ExceptionFilterUtils.java
new file mode 100644
index 0000000..44f3bec
--- /dev/null
+++ b/hyracks/hyracks-control/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/job/ExceptionFilterUtils.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.hyracks.control.cc.job;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * @author yingyib
+ */
+public class ExceptionFilterUtils {
+
+    public static List<Exception> getActualExceptions(List<Exception> allExceptions) {
+        List<Exception> exceptions = new ArrayList<Exception>();
+        for (Exception exception : allExceptions) {
+            if (possibleRootCause(exception)) {
+                exceptions.add(exception);
+            }
+        }
+        return exceptions;
+    }
+
+    private static boolean possibleRootCause(Throwable exception) {
+        Throwable cause = exception;
+        while ((cause = cause.getCause()) != null) {
+            if (cause instanceof java.lang.InterruptedException
+                    || cause instanceof java.nio.channels.ClosedChannelException) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+}
diff --git a/hyracks/hyracks-control/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/job/JobRun.java b/hyracks/hyracks-control/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/job/JobRun.java
index 9cd7886..2166620 100644
--- a/hyracks/hyracks-control/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/job/JobRun.java
+++ b/hyracks/hyracks-control/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/job/JobRun.java
@@ -347,7 +347,9 @@
                                 taskAttempt.put("end-time", ta.getEndTime());
                                 List<Exception> exceptions = ta.getExceptions();
                                 if (exceptions != null && !exceptions.isEmpty()) {
-                                    for(Exception exception : exceptions){
+                                    List<Exception> filteredExceptions = ExceptionFilterUtils
+                                            .getActualExceptions(exceptions);
+                                    for (Exception exception : filteredExceptions) {
                                         StringWriter exceptionWriter = new StringWriter();
                                         exception.printStackTrace(new PrintWriter(exceptionWriter));
                                         taskAttempt.put("failure-details", exceptionWriter.toString());
diff --git a/hyracks/hyracks-control/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/work/JobCleanupWork.java b/hyracks/hyracks-control/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/work/JobCleanupWork.java
index 3b29b52..6e8ddf0 100644
--- a/hyracks/hyracks-control/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/work/JobCleanupWork.java
+++ b/hyracks/hyracks-control/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/work/JobCleanupWork.java
@@ -59,7 +59,9 @@
         }
         Set<String> targetNodes = run.getParticipatingNodeIds();
         run.getCleanupPendingNodeIds().addAll(targetNodes);
-        run.setPendingStatus(status, exceptions);
+        if (run.getPendingStatus() != JobStatus.FAILURE && run.getPendingStatus() != JobStatus.TERMINATED) {
+            run.setPendingStatus(status, exceptions);
+        }
         if (targetNodes != null && !targetNodes.isEmpty()) {
             for (String n : targetNodes) {
                 NodeControllerState ncs = ccs.getNodeMap().get(n);
diff --git a/hyracks/hyracks-control/hyracks-control-common/pom.xml b/hyracks/hyracks-control/hyracks-control-common/pom.xml
index cc5853a..1f3c764 100644
--- a/hyracks/hyracks-control/hyracks-control-common/pom.xml
+++ b/hyracks/hyracks-control/hyracks-control-common/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-control</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -41,7 +41,7 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-api</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
diff --git a/hyracks/hyracks-control/hyracks-control-nc/pom.xml b/hyracks/hyracks-control/hyracks-control-nc/pom.xml
index ada388d..006a07b 100644
--- a/hyracks/hyracks-control/hyracks-control-nc/pom.xml
+++ b/hyracks/hyracks-control/hyracks-control-nc/pom.xml
@@ -19,7 +19,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-control</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -40,19 +40,19 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-control-common</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-net</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-comm</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   	</dependency>
   </dependencies>
   <reporting>
diff --git a/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/work/NotifyTaskFailureWork.java b/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/work/NotifyTaskFailureWork.java
index c4784ff..56379d2 100644
--- a/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/work/NotifyTaskFailureWork.java
+++ b/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/work/NotifyTaskFailureWork.java
@@ -43,6 +43,7 @@
                 dpm.abortReader(jobId);
             }
             ncs.getClusterController().notifyTaskFailure(jobId, task.getTaskAttemptId(), ncs.getId(), exceptions);
+            //exceptions.get(0).printStackTrace();
         } catch (Exception e) {
             e.printStackTrace();
         }
diff --git a/hyracks/hyracks-control/pom.xml b/hyracks/hyracks-control/pom.xml
index 7502ed7..7b43c1f 100644
--- a/hyracks/hyracks-control/pom.xml
+++ b/hyracks/hyracks-control/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <modules>
diff --git a/hyracks/hyracks-data/hyracks-data-std/pom.xml b/hyracks/hyracks-data/hyracks-data-std/pom.xml
index d4c5d0d..0758c9a 100644
--- a/hyracks/hyracks-data/hyracks-data-std/pom.xml
+++ b/hyracks/hyracks-data/hyracks-data-std/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-data</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -41,7 +41,7 @@
   <dependency>
   	<groupId>edu.uci.ics.hyracks</groupId>
   	<artifactId>hyracks-api</artifactId>
-  	<version>0.2.9-SNAPSHOT</version>
+  	<version>0.2.10-SNAPSHOT</version>
   </dependency>
   </dependencies>
 </project>
diff --git a/hyracks/hyracks-data/pom.xml b/hyracks/hyracks-data/pom.xml
index 5e17d2b..a5ffd98 100644
--- a/hyracks/hyracks-data/pom.xml
+++ b/hyracks/hyracks-data/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <modules>
diff --git a/hyracks/hyracks-dataflow-common/pom.xml b/hyracks/hyracks-dataflow-common/pom.xml
index 279b128..d779ca4 100644
--- a/hyracks/hyracks-dataflow-common/pom.xml
+++ b/hyracks/hyracks-dataflow-common/pom.xml
@@ -19,7 +19,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -40,14 +40,14 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-api</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-data-std</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   	</dependency>
   </dependencies>
 </project>
diff --git a/hyracks/hyracks-dataflow-hadoop/pom.xml b/hyracks/hyracks-dataflow-hadoop/pom.xml
index a8231a5..5c05956 100644
--- a/hyracks/hyracks-dataflow-hadoop/pom.xml
+++ b/hyracks/hyracks-dataflow-hadoop/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -40,14 +40,14 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-api</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-dataflow-common</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
@@ -67,7 +67,7 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-dataflow-std</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   </dependencies>
diff --git a/hyracks/hyracks-dataflow-std/pom.xml b/hyracks/hyracks-dataflow-std/pom.xml
index c97c3c4..dafc03f 100644
--- a/hyracks/hyracks-dataflow-std/pom.xml
+++ b/hyracks/hyracks-dataflow-std/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -41,14 +41,14 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-api</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-dataflow-common</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/join/InMemoryHashJoin.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/join/InMemoryHashJoin.java
index d02d65c..60e9c40 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/join/InMemoryHashJoin.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/join/InMemoryHashJoin.java
@@ -119,7 +119,7 @@
                     accessorBuild.reset(buffers.get(bIndex));
                     int c = tpComparator.compare(accessorProbe, i, accessorBuild, tIndex);
                     if (c == 0) {
-                    	boolean predEval = ( (predEvaluator == null) || predEvaluator.evaluate(accessorProbe, i, accessorBuild, tIndex) );
+                    	boolean predEval = evaluatePredicate(i, tIndex);
                     	if(predEval){
                     		matchFound = true;
                             appendToResult(i, tIndex, writer);
@@ -155,6 +155,15 @@
         buffer.position(0);
         buffer.limit(buffer.capacity());
     }
+    
+    private boolean evaluatePredicate(int tIx1, int tIx2){
+    	if(reverseOutputOrder){		//Role Reversal Optimization is triggered
+    		return ( (predEvaluator == null) || predEvaluator.evaluate(accessorBuild, tIx2, accessorProbe, tIx1) );
+    	}
+    	else {
+    		return ( (predEvaluator == null) || predEvaluator.evaluate(accessorProbe, tIx1, accessorBuild, tIx2) );
+    	}
+    }
 
     private void appendToResult(int probeSidetIx, int buildSidetIx, IFrameWriter writer) throws HyracksDataException {
         if (!reverseOutputOrder) {
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/join/NestedLoopJoin.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/join/NestedLoopJoin.java
index 2f719fa..979ef59 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/join/NestedLoopJoin.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/join/NestedLoopJoin.java
@@ -49,6 +49,8 @@
     private final boolean isLeftOuter;
     private final ArrayTupleBuilder nullTupleBuilder;
     private final IPredicateEvaluator predEvaluator;
+    private boolean isReversed;		//Added for handling correct calling for predicate-evaluator upon recursive calls (in OptimizedHybridHashJoin) that cause role-reversal
+
     
     public NestedLoopJoin(IHyracksTaskContext ctx, FrameTupleAccessor accessor0, FrameTupleAccessor accessor1,
             ITuplePairComparator comparators, int memSize, IPredicateEvaluator predEval, boolean isLeftOuter, INullWriter[] nullWriters1)
@@ -63,6 +65,7 @@
         this.outBuffers = new ArrayList<ByteBuffer>();
         this.memSize = memSize;
         this.predEvaluator = predEval;
+        this.isReversed = false;
         this.ctx = ctx;
 
         this.isLeftOuter = isLeftOuter;
@@ -133,7 +136,7 @@
             boolean matchFound = false;
             for (int j = 0; j < tupleCount1; ++j) {
                 int c = compare(accessorOuter, i, accessorInner, j);
-                boolean prdEval = (predEvaluator == null) || (predEvaluator.evaluate(accessorOuter, i, accessorInner, j));
+                boolean prdEval = evaluatePredicate(i, j);
                 if (c == 0 && prdEval) {
                 	matchFound = true;
                     if (!appender.appendConcat(accessorOuter, i, accessorInner, j)) {
@@ -165,6 +168,15 @@
             }
         }
     }
+    
+    private boolean evaluatePredicate(int tIx1, int tIx2){
+    	if(isReversed){		//Role Reversal Optimization is triggered
+    		return ( (predEvaluator == null) || predEvaluator.evaluate(accessorInner, tIx2, accessorOuter, tIx1) );
+    	}
+    	else {
+    		return ( (predEvaluator == null) || predEvaluator.evaluate(accessorOuter, tIx1, accessorInner, tIx2) );
+    	}
+    }
 
     public void closeCache() throws HyracksDataException {
         if (runFileWriter != null) {
@@ -206,4 +218,8 @@
         }
         return 0;
     }
+    
+    public void setIsReversed(boolean b){
+    	this.isReversed = b;
+    }
 }
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/join/OptimizedHybridHashJoin.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/join/OptimizedHybridHashJoin.java
index cd32c81..6bc810e 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/join/OptimizedHybridHashJoin.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/join/OptimizedHybridHashJoin.java
@@ -99,6 +99,7 @@
     private int freeFramesCounter; //Used for partition tuning
     
     private boolean isTableEmpty;	//Added for handling the case, where build side is empty (tableSize is 0)
+    private boolean isReversed;		//Added for handling correct calling for predicate-evaluator upon recursive calls that cause role-reversal
     
     public OptimizedHybridHashJoin(IHyracksTaskContext ctx, int memForJoin, int numOfPartitions, String rel0Name,
             String rel1Name, int[] keys0, int[] keys1, IBinaryComparator[] comparators, RecordDescriptor buildRd,
@@ -125,6 +126,7 @@
         this.predEvaluator = predEval;
         this.isLeftOuter = false;
         this.nullWriters1 = null;
+        this.isReversed = false;
 
     }
 
@@ -153,7 +155,8 @@
         
         this.predEvaluator = predEval;
         this.isLeftOuter = isLeftOuter;
-
+        this.isReversed = false;
+        
         this.nullWriters1 = isLeftOuter ? new INullWriter[nullWriterFactories1.length] : null;
         if (isLeftOuter) {
             for (int i = 0; i < nullWriterFactories1.length; i++) {
@@ -441,7 +444,7 @@
         this.inMemJoiner = new InMemoryHashJoin(ctx, inMemTupCount,
                 new FrameTupleAccessor(ctx.getFrameSize(), probeRd), probeHpc, new FrameTupleAccessor(
                         ctx.getFrameSize(), buildRd), buildHpc, new FrameTuplePairComparator(probeKeys, buildKeys,
-                        comparators), isLeftOuter, nullWriters1, table, predEvaluator);
+                        comparators), isLeftOuter, nullWriters1, table, predEvaluator, isReversed);
     }
 
     private void cacheInMemJoin() throws HyracksDataException {
@@ -639,4 +642,8 @@
     public boolean isTableEmpty() {
         return this.isTableEmpty;
     }
+    
+    public void setIsReversed(boolean b){
+    	this.isReversed = b;
+    }
 }
diff --git a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/join/OptimizedHybridHashJoinOperatorDescriptor.java b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/join/OptimizedHybridHashJoinOperatorDescriptor.java
index 95b7a3c..4e9376d 100644
--- a/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/join/OptimizedHybridHashJoinOperatorDescriptor.java
+++ b/hyracks/hyracks-dataflow-std/src/main/java/edu/uci/ics/hyracks/dataflow/std/join/OptimizedHybridHashJoinOperatorDescriptor.java
@@ -19,6 +19,8 @@
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.BitSet;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 
 import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
 import edu.uci.ics.hyracks.api.dataflow.ActivityId;
@@ -117,6 +119,8 @@
     
     private final boolean isLeftOuter;
     private final INullWriterFactory[] nullWriterFactories1;
+    
+    private static final Logger LOGGER = Logger.getLogger(OptimizedHybridHashJoinOperatorDescriptor.class.getName());
 
     public OptimizedHybridHashJoinOperatorDescriptor(IOperatorDescriptorRegistry spec, int memsize, int inputsize0,
             double factor, int[] keys0, int[] keys1, IBinaryHashFunctionFamily[] hashFunctionGeneratorFactories,
@@ -139,8 +143,6 @@
         this.predEvaluatorFactory = predEvaluatorFactory;
         this.isLeftOuter = isLeftOuter;
         this.nullWriterFactories1 = nullWriterFactories1;
-        
-
     }
 
     public OptimizedHybridHashJoinOperatorDescriptor(IOperatorDescriptorRegistry spec, int memsize, int inputsize0,
@@ -207,7 +209,7 @@
     }
 
     public static class BuildAndPartitionTaskState extends AbstractStateObject {
-
+    	
         private int memForJoin;
         private int numOfPartitions;
         private OptimizedHybridHashJoin hybridHJ;
@@ -303,6 +305,7 @@
                 public void close() throws HyracksDataException {
                     state.hybridHJ.closeBuild();
                     ctx.setStateObject(state);
+                    LOGGER.log(Level.FINE, "OptimizedHybridHashJoin closed its build phase");
                 }
 
                 @Override
@@ -323,7 +326,7 @@
      * Hybrid Hash Join recursively on them.
      */
     private class ProbeAndJoinActivityNode extends AbstractActivityNode {
-
+    	
         private static final long serialVersionUID = 1L;
 
         private final ActivityId buildAid;
@@ -423,9 +426,11 @@
                             hashFunctionGeneratorFactories).createPartitioner(level);
                     ITuplePartitionComputer buildHpc = new FieldHashPartitionComputerFamily(buildKeys,
                             hashFunctionGeneratorFactories).createPartitioner(level);
-
+                    
                     long buildPartSize = ohhj.getBuildPartitionSize(pid) / ctx.getFrameSize();
                     long probePartSize = ohhj.getProbePartitionSize(pid) / ctx.getFrameSize();
+                    
+                    LOGGER.log(Level.FINE,"Joining Partition Pairs (pid "+pid+") - (level "+level+") - BuildSize:\t"+buildPartSize+"\tProbeSize:\t"+probePartSize+" - MemForJoin "+(state.memForJoin));
 
                     //Apply in-Mem HJ if possible
                     if ((buildPartSize < state.memForJoin) || (probePartSize < state.memForJoin)) {
@@ -460,7 +465,7 @@
                     else {
                         OptimizedHybridHashJoin rHHj;
                         if (isLeftOuter || buildPartSize < probePartSize) { //Build Side is smaller
-
+                        	LOGGER.log(Level.FINE,"\tApply RecursiveHHJ for (pid "+pid+") - (level "+level+") [buildSize is smaller]");
                             int n = getNumberOfPartitions(state.memForJoin, (int) buildPartSize, fudgeFactor,
                                     nPartitions);
                            
@@ -503,6 +508,7 @@
                                 }
 
                             } else { //Switch to NLJ (Further recursion seems not to be useful)
+                            	LOGGER.log(Level.FINE,"\tSwitched to NLJ for (pid "+pid+") - (level "+level+") (reverse false) [coming from buildSize was smaller]");
                                 for (int rPid = rPStatus.nextSetBit(0); rPid >= 0; rPid = rPStatus.nextSetBit(rPid + 1)) {
                                     RunFileReader rbrfw = rHHj.getBuildRFReader(rPid);
                                     RunFileReader rprfw = rHHj.getProbeRFReader(rPid);
@@ -515,19 +521,21 @@
                                     int probeSideInTups = rHHj.getProbePartitionSizeInTup(rPid);
                                     if (isLeftOuter || buildSideInTups < probeSideInTups) {
                                         applyNestedLoopJoin(probeRd, buildRd, state.memForJoin, rbrfw, rprfw,
-                                                nljComparator0);
+                                                nljComparator0, false);
                                     } else {
                                         applyNestedLoopJoin(buildRd, probeRd, state.memForJoin, rprfw, rbrfw,
-                                                nljComparator1);
+                                                nljComparator1, false);
                                     }
                                 }
                             }
                         } else { //Role Reversal (Probe Side is smaller)
+                        	LOGGER.log(Level.FINE,"\tApply RecursiveHHJ for (pid "+pid+") - (level "+level+") WITH REVERSAL [probeSize is smaller]");
                             int n = getNumberOfPartitions(state.memForJoin, (int) probePartSize, fudgeFactor,
                                     nPartitions);
                             
                             rHHj = new OptimizedHybridHashJoin(ctx, state.memForJoin, n, BUILD_REL, PROBE_REL,
                                     buildKeys, probeKeys, comparators, buildRd, probeRd, buildHpc, probeHpc, predEvaluator);
+                            rHHj.setIsReversed(true);	//Added to use predicateEvaluator (for inMemoryHashJoin) correctly
 
                             probeSideReader.open();
                             rHHj.initBuild();
@@ -561,7 +569,8 @@
                                     joinPartitionPair(rHHj, rprfw, rbrfw, rPid, afterMax, (level + 1));
                                 }
                             } else { //Switch to NLJ (Further recursion seems not to be effective)
-                                for (int rPid = rPStatus.nextSetBit(0); rPid >= 0; rPid = rPStatus.nextSetBit(rPid + 1)) {
+                            	LOGGER.log(Level.FINE,"\tSwitched to NLJ for (pid "+pid+") - (level "+level+") (reverse true) [coming from probeSize was smaller]");
+                            	for (int rPid = rPStatus.nextSetBit(0); rPid >= 0; rPid = rPStatus.nextSetBit(rPid + 1)) {
                                     RunFileReader rbrfw = rHHj.getBuildRFReader(rPid);
                                     RunFileReader rprfw = rHHj.getProbeRFReader(rPid);
                                     
@@ -573,10 +582,10 @@
                                     long probeSideSize = rprfw.getFileSize();
                                     if (buildSideSize > probeSideSize) {
                                         applyNestedLoopJoin(buildRd, probeRd, state.memForJoin, rbrfw, rprfw,
-                                                nljComparator1);
+                                                nljComparator1, true);
                                     } else {
                                         applyNestedLoopJoin(probeRd, buildRd, state.memForJoin, rprfw, rbrfw,
-                                                nljComparator0);
+                                                nljComparator0, true);
                                     }
                                 }
                             }
@@ -590,7 +599,7 @@
                         RecordDescriptor probeRDesc, ITuplePartitionComputer hpcRepLarger,
                         ITuplePartitionComputer hpcRepSmaller, RunFileReader bReader, RunFileReader pReader, boolean reverse, int pid)
                         throws HyracksDataException {
-
+                	LOGGER.log(Level.FINE,"\t(pid "+pid+") - applyInMemHashJoin (reversal "+reverse+")");
                     ISerializableTable table = new SerializableHashTable(tabSize, ctx);
                     InMemoryHashJoin joiner = new InMemoryHashJoin(ctx, tabSize, new FrameTupleAccessor(
                             ctx.getFrameSize(), probeRDesc), hpcRepLarger, new FrameTupleAccessor(ctx.getFrameSize(),
@@ -619,9 +628,9 @@
                 }
 
                 private void applyNestedLoopJoin(RecordDescriptor outerRd, RecordDescriptor innerRd, int memorySize,
-                        RunFileReader outerReader, RunFileReader innerReader, ITuplePairComparator nljComparator)
+                        RunFileReader outerReader, RunFileReader innerReader, ITuplePairComparator nljComparator, boolean reverse)
                         throws HyracksDataException {
-
+                	
                     NestedLoopJoin nlj = new NestedLoopJoin(ctx, new FrameTupleAccessor(ctx.getFrameSize(), outerRd),
                             new FrameTupleAccessor(ctx.getFrameSize(), innerRd), nljComparator, memorySize, predEvaluator, false, null);
 
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/FrameSorter.java
index db70a62..f71ee1d 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/FrameSorter.java
@@ -46,6 +46,7 @@
 
     private int dataFrameCount;
     private int[] tPointers;
+    private int[] tPointersTemp;
     private int tupleCount;
 
     public FrameSorter(IHyracksTaskContext ctx, int[] sortFields,
@@ -116,7 +117,8 @@
             }
         }
         if (tupleCount > 0) {
-            sort(tPointers, 0, tupleCount);
+            tPointersTemp = new int[tPointers.length];
+            sort(0, tupleCount);
         }
     }
 
@@ -142,75 +144,73 @@
         }
     }
 
-    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;
+    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);
                 }
-                if (cmp == 0) {
-                    swap(tPointers, a++, b);
-                }
-                ++b;
             }
-            while (c >= b) {
-                int cmp = compare(tPointers, c, mi, mj, mv);
-                if (cmp < 0) {
-                    break;
-                }
-                if (cmp == 0) {
-                    swap(tPointers, c, d--);
-                }
-                --c;
+            /** 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++;
             }
-            if (b > c)
-                break;
-            swap(tPointers, b++, c--);
+            targetPos++;
         }
-
-        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 (pos1 <= end1) {
+            int rest = end1 - pos1 + 1;
+            System.arraycopy(tPointers, pos1 * 4, tPointersTemp, targetPos * 4, rest * 4);
         }
-        if ((s = d - c) > 1) {
-            sort(tPointers, n - s, s);
+        if (pos2 <= end2) {
+            int rest = end2 - pos2 + 1;
+            System.arraycopy(tPointers, pos2 * 4, tPointersTemp, targetPos * 4, rest * 4);
         }
     }
 
-    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 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 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) {
+    private int compare(int tp1, int tp2) {
         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;
         }
diff --git a/hyracks/hyracks-dist/pom.xml b/hyracks/hyracks-dist/pom.xml
index d995fac..ab7ea53 100755
--- a/hyracks/hyracks-dist/pom.xml
+++ b/hyracks/hyracks-dist/pom.xml
@@ -18,7 +18,7 @@
 	<parent>
 		<artifactId>hyracks</artifactId>
 		<groupId>edu.uci.ics.hyracks</groupId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 	</parent>
 
 	<artifactId>hyracks-dist</artifactId>
diff --git a/hyracks/hyracks-documentation/pom.xml b/hyracks/hyracks-documentation/pom.xml
index db092fd..4bc3f25 100644
--- a/hyracks/hyracks-documentation/pom.xml
+++ b/hyracks/hyracks-documentation/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
diff --git a/hyracks/hyracks-examples/btree-example/btreeclient/pom.xml b/hyracks/hyracks-examples/btree-example/btreeclient/pom.xml
index 7b0a78b..27ab200 100644
--- a/hyracks/hyracks-examples/btree-example/btreeclient/pom.xml
+++ b/hyracks/hyracks-examples/btree-example/btreeclient/pom.xml
@@ -20,26 +20,26 @@
   <parent>
     <groupId>edu.uci.ics.hyracks.examples</groupId>
     <artifactId>btree-example</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <dependencies>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-dataflow-std</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-btree</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks.examples.btree</groupId>
   		<artifactId>btreehelper</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
diff --git a/hyracks/hyracks-examples/btree-example/btreehelper/pom.xml b/hyracks/hyracks-examples/btree-example/btreehelper/pom.xml
index 6191c48..85eadf1 100644
--- a/hyracks/hyracks-examples/btree-example/btreehelper/pom.xml
+++ b/hyracks/hyracks-examples/btree-example/btreehelper/pom.xml
@@ -20,32 +20,32 @@
   <parent>
     <groupId>edu.uci.ics.hyracks.examples</groupId>
     <artifactId>btree-example</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <dependencies>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-dataflow-std</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-btree</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-api</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-data-std</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   	</dependency>
   </dependencies>
   <build>
diff --git a/hyracks/hyracks-examples/btree-example/btreeserver/pom.xml b/hyracks/hyracks-examples/btree-example/btreeserver/pom.xml
index 1d7e6d2..3d3dc73 100644
--- a/hyracks/hyracks-examples/btree-example/btreeserver/pom.xml
+++ b/hyracks/hyracks-examples/btree-example/btreeserver/pom.xml
@@ -16,13 +16,13 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>edu.uci.ics.hyracks.examples.btree</groupId>
   <artifactId>btreeserver</artifactId>
-  <version>0.2.9-SNAPSHOT</version>
+  <version>0.2.10-SNAPSHOT</version>
   <name>btreeserver</name>
 
   <parent>
     <groupId>edu.uci.ics.hyracks.examples</groupId>
     <artifactId>btree-example</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -77,20 +77,20 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks.examples.btree</groupId>
   		<artifactId>btreehelper</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-control-cc</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-control-nc</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
diff --git a/hyracks/hyracks-examples/btree-example/pom.xml b/hyracks/hyracks-examples/btree-example/pom.xml
index 69acce12..dcab262 100644
--- a/hyracks/hyracks-examples/btree-example/pom.xml
+++ b/hyracks/hyracks-examples/btree-example/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-examples</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <modules>
diff --git a/hyracks/hyracks-examples/hadoop-compat-example/hadoopcompatclient/pom.xml b/hyracks/hyracks-examples/hadoop-compat-example/hadoopcompatclient/pom.xml
index e546379..b5dd798 100644
--- a/hyracks/hyracks-examples/hadoop-compat-example/hadoopcompatclient/pom.xml
+++ b/hyracks/hyracks-examples/hadoop-compat-example/hadoopcompatclient/pom.xml
@@ -21,20 +21,20 @@
   <parent>
     <groupId>edu.uci.ics.hyracks.examples</groupId>
     <artifactId>hadoop-compat-example</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <dependencies>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-dataflow-std</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks.examples.compat</groupId>
   		<artifactId>hadoopcompathelper</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
diff --git a/hyracks/hyracks-examples/hadoop-compat-example/hadoopcompathelper/pom.xml b/hyracks/hyracks-examples/hadoop-compat-example/hadoopcompathelper/pom.xml
index d55ee73..2b703b2 100644
--- a/hyracks/hyracks-examples/hadoop-compat-example/hadoopcompathelper/pom.xml
+++ b/hyracks/hyracks-examples/hadoop-compat-example/hadoopcompathelper/pom.xml
@@ -21,20 +21,20 @@
   <parent>
     <groupId>edu.uci.ics.hyracks.examples</groupId>
     <artifactId>hadoop-compat-example</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <dependencies>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-dataflow-std</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-api</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   </dependencies>
diff --git a/hyracks/hyracks-examples/hadoop-compat-example/hadoopcompatserver/pom.xml b/hyracks/hyracks-examples/hadoop-compat-example/hadoopcompatserver/pom.xml
index ccde502..ba30424 100644
--- a/hyracks/hyracks-examples/hadoop-compat-example/hadoopcompatserver/pom.xml
+++ b/hyracks/hyracks-examples/hadoop-compat-example/hadoopcompatserver/pom.xml
@@ -16,13 +16,13 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>edu.uci.ics.hyracks.examples.compat</groupId>
   <artifactId>hadoopcompatserver</artifactId>
-  <version>0.2.9-SNAPSHOT</version>
+  <version>0.2.10-SNAPSHOT</version>
   <name>hadoopcompatserver</name>
 
   <parent>
     <groupId>edu.uci.ics.hyracks.examples</groupId>
     <artifactId>hadoop-compat-example</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -74,7 +74,7 @@
       <plugin>
       	<groupId>edu.uci.ics.hyracks</groupId>
       	<artifactId>hyracks-virtualcluster-maven-plugin</artifactId>
-      	<version>0.2.9-SNAPSHOT</version>
+      	<version>0.2.10-SNAPSHOT</version>
         <configuration>
           <hyracksServerHome>${basedir}/target/hadoopcompatserver-${project.version}-binary-assembly</hyracksServerHome>
           <jvmOptions>${jvm.extraargs}</jvmOptions>
@@ -149,27 +149,27 @@
      <dependency>
         <groupId>edu.uci.ics.hyracks.examples.compat</groupId>
         <artifactId>hadoopcompathelper</artifactId>
-        <version>0.2.9-SNAPSHOT</version>
+        <version>0.2.10-SNAPSHOT</version>
         <scope>compile</scope>
      </dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-control-cc</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-control-nc</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
      <dependency>
         <groupId>edu.uci.ics.hyracks.examples.compat</groupId>
   	    <artifactId>hadoopcompatclient</artifactId>
-  	    <version>0.2.9-SNAPSHOT</version>
+  	    <version>0.2.10-SNAPSHOT</version>
   	    <type>jar</type>
   	    <scope>test</scope>
      </dependency>
diff --git a/hyracks/hyracks-examples/hadoop-compat-example/pom.xml b/hyracks/hyracks-examples/hadoop-compat-example/pom.xml
index 1cd43d6..5588134 100644
--- a/hyracks/hyracks-examples/hadoop-compat-example/pom.xml
+++ b/hyracks/hyracks-examples/hadoop-compat-example/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-examples</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <modules>
@@ -43,7 +43,7 @@
       <dependency>
          <groupId>edu.uci.ics.hyracks</groupId>
          <artifactId>hyracks-hadoop-compat</artifactId>
-         <version>0.2.9-SNAPSHOT</version>
+         <version>0.2.10-SNAPSHOT</version>
          <type>jar</type>
          <scope>compile</scope>
       </dependency>
diff --git a/hyracks/hyracks-examples/hyracks-integration-tests/pom.xml b/hyracks/hyracks-examples/hyracks-integration-tests/pom.xml
index f34a22f..4893be4 100644
--- a/hyracks/hyracks-examples/hyracks-integration-tests/pom.xml
+++ b/hyracks/hyracks-examples/hyracks-integration-tests/pom.xml
@@ -20,7 +20,7 @@
 	<parent>
 		<groupId>edu.uci.ics.hyracks</groupId>
 		<artifactId>hyracks-examples</artifactId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 	</parent>
 	<build>
 		<plugins>
@@ -46,75 +46,75 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-dataflow-std</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-control-cc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-control-nc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<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>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-storage-am-rtree</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-storage-am-lsm-btree</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-storage-am-lsm-rtree</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-storage-am-lsm-invertedindex</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-test-support</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>test</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-data-std</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 		</dependency>
   	    <dependency>
             <groupId>edu.uci.ics.hyracks</groupId>
             <artifactId>hyracks-client</artifactId>
-            <version>0.2.9-SNAPSHOT</version>
+            <version>0.2.10-SNAPSHOT</version>
             <type>jar</type>
             <scope>compile</scope>
         </dependency>
diff --git a/hyracks/hyracks-examples/pom.xml b/hyracks/hyracks-examples/pom.xml
index 5c57358..08f4a90 100644
--- a/hyracks/hyracks-examples/pom.xml
+++ b/hyracks/hyracks-examples/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <modules>
diff --git a/hyracks/hyracks-examples/text-example/pom.xml b/hyracks/hyracks-examples/text-example/pom.xml
index 2729336..ed9924a 100644
--- a/hyracks/hyracks-examples/text-example/pom.xml
+++ b/hyracks/hyracks-examples/text-example/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-examples</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <modules>
diff --git a/hyracks/hyracks-examples/text-example/textclient/pom.xml b/hyracks/hyracks-examples/text-example/textclient/pom.xml
index e066e24..6923241 100644
--- a/hyracks/hyracks-examples/text-example/textclient/pom.xml
+++ b/hyracks/hyracks-examples/text-example/textclient/pom.xml
@@ -20,20 +20,20 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>text-example</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <dependencies>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-dataflow-std</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>texthelper</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
diff --git a/hyracks/hyracks-examples/text-example/texthelper/pom.xml b/hyracks/hyracks-examples/text-example/texthelper/pom.xml
index 8389688..0c708a1 100644
--- a/hyracks/hyracks-examples/text-example/texthelper/pom.xml
+++ b/hyracks/hyracks-examples/text-example/texthelper/pom.xml
@@ -20,26 +20,26 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>text-example</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <dependencies>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-dataflow-std</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-api</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-data-std</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   	</dependency>
   </dependencies>
   <build>
diff --git a/hyracks/hyracks-examples/text-example/textserver/pom.xml b/hyracks/hyracks-examples/text-example/textserver/pom.xml
index c11dc37..b12f823 100644
--- a/hyracks/hyracks-examples/text-example/textserver/pom.xml
+++ b/hyracks/hyracks-examples/text-example/textserver/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>text-example</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -73,7 +73,7 @@
       <plugin>
       	<groupId>edu.uci.ics.hyracks</groupId>
       	<artifactId>hyracks-virtualcluster-maven-plugin</artifactId>
-      	<version>0.2.9-SNAPSHOT</version>
+      	<version>0.2.10-SNAPSHOT</version>
         <configuration>
           <hyracksServerHome>${basedir}/target/textserver-${project.version}-binary-assembly</hyracksServerHome>
           <jvmOptions>${jvm.extraargs}</jvmOptions>
@@ -148,27 +148,27 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>texthelper</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-control-cc</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-control-nc</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>textclient</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>test</scope>
   	</dependency>
diff --git a/hyracks/hyracks-examples/tpch-example/pom.xml b/hyracks/hyracks-examples/tpch-example/pom.xml
index 2f37f82..1b5f2b5 100644
--- a/hyracks/hyracks-examples/tpch-example/pom.xml
+++ b/hyracks/hyracks-examples/tpch-example/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-examples</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <modules>
diff --git a/hyracks/hyracks-examples/tpch-example/tpchclient/pom.xml b/hyracks/hyracks-examples/tpch-example/tpchclient/pom.xml
index 8720bfc..a872ecd 100644
--- a/hyracks/hyracks-examples/tpch-example/tpchclient/pom.xml
+++ b/hyracks/hyracks-examples/tpch-example/tpchclient/pom.xml
@@ -19,20 +19,20 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>tpch-example</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <dependencies>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-dataflow-std</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-data-std</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   	</dependency>
   </dependencies>
   <build>
diff --git a/hyracks/hyracks-examples/tpch-example/tpchserver/pom.xml b/hyracks/hyracks-examples/tpch-example/tpchserver/pom.xml
index 5446c24..712ba4c 100644
--- a/hyracks/hyracks-examples/tpch-example/tpchserver/pom.xml
+++ b/hyracks/hyracks-examples/tpch-example/tpchserver/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>tpch-example</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -76,25 +76,25 @@
     <dependency>
         <groupId>edu.uci.ics.hyracks</groupId>
         <artifactId>hyracks-dataflow-std</artifactId>
-        <version>0.2.9-SNAPSHOT</version>
+        <version>0.2.10-SNAPSHOT</version>
         <scope>compile</scope>
     </dependency>
     <dependency>
     	<groupId>edu.uci.ics.hyracks</groupId>
     	<artifactId>hyracks-data-std</artifactId>
-    	<version>0.2.9-SNAPSHOT</version>
+    	<version>0.2.10-SNAPSHOT</version>
     </dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-control-cc</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-control-nc</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
diff --git a/hyracks/hyracks-hadoop-compat/pom.xml b/hyracks/hyracks-hadoop-compat/pom.xml
index 129584d..f6cfb71 100644
--- a/hyracks/hyracks-hadoop-compat/pom.xml
+++ b/hyracks/hyracks-hadoop-compat/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -94,7 +94,7 @@
     <dependency>
     	<groupId>edu.uci.ics.hyracks</groupId>
     	<artifactId>hyracks-dataflow-hadoop</artifactId>
-    	<version>0.2.9-SNAPSHOT</version>
+    	<version>0.2.10-SNAPSHOT</version>
     	<type>jar</type>
     	<scope>compile</scope>
     </dependency>
diff --git a/hyracks/hyracks-hdfs/hyracks-hdfs-0.20.2/pom.xml b/hyracks/hyracks-hdfs/hyracks-hdfs-0.20.2/pom.xml
index 7d024ab..b93365d 100644
--- a/hyracks/hyracks-hdfs/hyracks-hdfs-0.20.2/pom.xml
+++ b/hyracks/hyracks-hdfs/hyracks-hdfs-0.20.2/pom.xml
@@ -20,7 +20,7 @@
 	<parent>
 		<artifactId>hyracks-hdfs</artifactId>
 		<groupId>edu.uci.ics.hyracks</groupId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 	</parent>
 
 	<build>
@@ -112,7 +112,7 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-api</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
diff --git a/hyracks/hyracks-hdfs/hyracks-hdfs-0.23.1/pom.xml b/hyracks/hyracks-hdfs/hyracks-hdfs-0.23.1/pom.xml
index bbe0fe8..7cd1091 100644
--- a/hyracks/hyracks-hdfs/hyracks-hdfs-0.23.1/pom.xml
+++ b/hyracks/hyracks-hdfs/hyracks-hdfs-0.23.1/pom.xml
@@ -20,7 +20,7 @@
 	<parent>
 		<artifactId>hyracks-hdfs</artifactId>
 		<groupId>edu.uci.ics.hyracks</groupId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 	</parent>
 	<build>
 		<plugins>
@@ -216,7 +216,7 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-api</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
diff --git a/hyracks/hyracks-hdfs/hyracks-hdfs-core/pom.xml b/hyracks/hyracks-hdfs/hyracks-hdfs-core/pom.xml
index 3fd445d..b51d41d 100644
--- a/hyracks/hyracks-hdfs/hyracks-hdfs-core/pom.xml
+++ b/hyracks/hyracks-hdfs/hyracks-hdfs-core/pom.xml
@@ -1,26 +1,22 @@
 <?xml version="1.0"?>
-<!--
- ! 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.
- !-->
-<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>hyracks-hdfs-core</artifactId>
 	<name>hyracks-hdfs-core</name>
 	<parent>
 		<artifactId>hyracks-hdfs</artifactId>
 		<groupId>edu.uci.ics.hyracks</groupId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 	</parent>
 
 	<build>
@@ -66,6 +62,18 @@
 					</filesets>
 				</configuration>
 			</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-jar-plugin</artifactId>
+				<version>2.2</version>
+				<executions>
+					<execution>
+						<goals>
+							<goal>test-jar</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
 		</plugins>
 	</build>
 
@@ -192,31 +200,31 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-api</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-dataflow-std</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-dataflow-common</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-control-cc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<scope>test</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-control-nc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<scope>test</scope>
 		</dependency>
 		<dependency>
diff --git a/hyracks/hyracks-hdfs/pom.xml b/hyracks/hyracks-hdfs/pom.xml
index 428f701..b174d37 100644
--- a/hyracks/hyracks-hdfs/pom.xml
+++ b/hyracks/hyracks-hdfs/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <modules>
diff --git a/hyracks/hyracks-ipc/pom.xml b/hyracks/hyracks-ipc/pom.xml
index 911ff7c..fed59e6 100644
--- a/hyracks/hyracks-ipc/pom.xml
+++ b/hyracks/hyracks-ipc/pom.xml
@@ -19,7 +19,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
diff --git a/hyracks/hyracks-maven-plugins/hyracks-virtualcluster-maven-plugin/pom.xml b/hyracks/hyracks-maven-plugins/hyracks-virtualcluster-maven-plugin/pom.xml
index eabf8bf..5ffbf28 100644
--- a/hyracks/hyracks-maven-plugins/hyracks-virtualcluster-maven-plugin/pom.xml
+++ b/hyracks/hyracks-maven-plugins/hyracks-virtualcluster-maven-plugin/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-maven-plugins</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
diff --git a/hyracks/hyracks-maven-plugins/pom.xml b/hyracks/hyracks-maven-plugins/pom.xml
index 0586741..a2b8d03 100644
--- a/hyracks/hyracks-maven-plugins/pom.xml
+++ b/hyracks/hyracks-maven-plugins/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <dependencies>
diff --git a/hyracks/hyracks-net/pom.xml b/hyracks/hyracks-net/pom.xml
index cbcab9c..a188f4c 100644
--- a/hyracks/hyracks-net/pom.xml
+++ b/hyracks/hyracks-net/pom.xml
@@ -19,7 +19,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
diff --git a/hyracks/hyracks-server/pom.xml b/hyracks/hyracks-server/pom.xml
index 995b827..f691481 100644
--- a/hyracks/hyracks-server/pom.xml
+++ b/hyracks/hyracks-server/pom.xml
@@ -19,7 +19,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -88,14 +88,14 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-control-cc</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-control-nc</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
diff --git a/hyracks/hyracks-storage-am-bloomfilter/pom.xml b/hyracks/hyracks-storage-am-bloomfilter/pom.xml
index b3877da..a712ab4 100644
--- a/hyracks/hyracks-storage-am-bloomfilter/pom.xml
+++ b/hyracks/hyracks-storage-am-bloomfilter/pom.xml
@@ -19,7 +19,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -39,7 +39,7 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-common</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>  	
diff --git a/hyracks/hyracks-storage-am-btree/pom.xml b/hyracks/hyracks-storage-am-btree/pom.xml
index 5dad142..2746666 100644
--- a/hyracks/hyracks-storage-am-btree/pom.xml
+++ b/hyracks/hyracks-storage-am-btree/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -41,28 +41,28 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-common</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<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>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>  	
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-dataflow-common</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>  	
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-dataflow-std</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>  	
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeNonExistentKeyException.java b/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeNonExistentKeyException.java
deleted file mode 100644
index 7237046..0000000
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeNonExistentKeyException.java
+++ /dev/null
@@ -1,29 +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.hyracks.storage.am.btree.exceptions;
-
-public class BTreeNonExistentKeyException extends BTreeException {
-
-    private static final long serialVersionUID = 1L;
-
-    public BTreeNonExistentKeyException(Exception e) {
-        super(e);
-    }
-
-    public BTreeNonExistentKeyException(String message) {
-        super(message);
-    }
-}
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/frames/BTreeFieldPrefixNSMLeafFrame.java b/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/frames/BTreeFieldPrefixNSMLeafFrame.java
index b503c8b..93cde3d 100644
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/frames/BTreeFieldPrefixNSMLeafFrame.java
+++ b/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/frames/BTreeFieldPrefixNSMLeafFrame.java
@@ -25,8 +25,6 @@
 import edu.uci.ics.hyracks.storage.am.btree.api.IBTreeLeafFrame;
 import edu.uci.ics.hyracks.storage.am.btree.api.IPrefixSlotManager;
 import edu.uci.ics.hyracks.storage.am.btree.compressors.FieldPrefixCompressor;
-import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeDuplicateKeyException;
-import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeNonExistentKeyException;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTreeOpContext.PageValidationInfo;
 import edu.uci.ics.hyracks.storage.am.btree.impls.FieldPrefixPrefixTupleReference;
 import edu.uci.ics.hyracks.storage.am.btree.impls.FieldPrefixSlotManager;
@@ -37,6 +35,8 @@
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexTupleReference;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexTupleWriter;
 import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
+import edu.uci.ics.hyracks.storage.am.common.exceptions.TreeIndexDuplicateKeyException;
+import edu.uci.ics.hyracks.storage.am.common.exceptions.TreeIndexNonExistentKeyException;
 import edu.uci.ics.hyracks.storage.am.common.frames.FrameOpSpaceStatus;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.FindTupleMode;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.FindTupleNoExactMatchPolicy;
@@ -370,7 +370,7 @@
         int tupleIndex = slotManager.decodeSecondSlotField(slot);
         // Error indicator is set if there is an exact match.
         if (tupleIndex == slotManager.getErrorIndicator()) {
-            throw new BTreeDuplicateKeyException("Trying to insert duplicate key into leaf node.");
+            throw new TreeIndexDuplicateKeyException("Trying to insert duplicate key into leaf node.");
         }
         return slot;
     }
@@ -382,7 +382,7 @@
         int tupleIndex = slotManager.decodeSecondSlotField(slot);
         // Error indicator is set if there is an exact match.
         if (tupleIndex == slotManager.getErrorIndicator()) {
-            throw new BTreeDuplicateKeyException("Trying to insert duplicate key into leaf node.");
+            throw new TreeIndexDuplicateKeyException("Trying to insert duplicate key into leaf node.");
         }
         return slot;
     }
@@ -411,7 +411,7 @@
         int tupleIndex = slotManager.decodeSecondSlotField(slot);
         // Error indicator is set if there is no exact match.
         if (tupleIndex == slotManager.getErrorIndicator()) {
-            throw new BTreeNonExistentKeyException("Trying to update a tuple with a nonexistent key in leaf node.");
+            throw new TreeIndexNonExistentKeyException("Trying to update a tuple with a nonexistent key in leaf node.");
         }
         return slot;
     }
@@ -423,7 +423,7 @@
         int tupleIndex = slotManager.decodeSecondSlotField(slot);
         // Error indicator is set if there is no exact match.
         if (tupleIndex == slotManager.getErrorIndicator()) {
-            throw new BTreeNonExistentKeyException("Trying to delete a tuple with a nonexistent key in leaf node.");
+            throw new TreeIndexNonExistentKeyException("Trying to delete a tuple with a nonexistent key in leaf node.");
         }
         return slot;
     }
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 1974989..187cd52 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
@@ -20,14 +20,14 @@
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
 import edu.uci.ics.hyracks.storage.am.btree.api.IBTreeLeafFrame;
-import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeDuplicateKeyException;
-import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeNonExistentKeyException;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTreeOpContext.PageValidationInfo;
 import edu.uci.ics.hyracks.storage.am.common.api.ISplitKey;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexFrame;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexTupleReference;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexTupleWriter;
 import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
+import edu.uci.ics.hyracks.storage.am.common.exceptions.TreeIndexDuplicateKeyException;
+import edu.uci.ics.hyracks.storage.am.common.exceptions.TreeIndexNonExistentKeyException;
 import edu.uci.ics.hyracks.storage.am.common.frames.TreeIndexNSMFrame;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.FindTupleMode;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.FindTupleNoExactMatchPolicy;
@@ -72,7 +72,7 @@
                 FindTupleNoExactMatchPolicy.HIGHER_KEY);
         // Error indicator is set if there is an exact match.
         if (tupleIndex == slotManager.getErrorIndicator()) {
-            throw new BTreeDuplicateKeyException("Trying to insert duplicate key into leaf node.");
+            throw new TreeIndexDuplicateKeyException("Trying to insert duplicate key into leaf node.");
         }
         return tupleIndex;
     }
@@ -83,7 +83,7 @@
                 FindTupleNoExactMatchPolicy.HIGHER_KEY);
         // Error indicator is set if there is no exact match.
         if (tupleIndex == slotManager.getErrorIndicator() || tupleIndex == slotManager.getGreatestKeyIndicator()) {
-            throw new BTreeNonExistentKeyException("Trying to update a tuple with a nonexistent key in leaf node.");
+            throw new TreeIndexNonExistentKeyException("Trying to update a tuple with a nonexistent key in leaf node.");
         }
         return tupleIndex;
     }
@@ -121,7 +121,7 @@
                 FindTupleNoExactMatchPolicy.HIGHER_KEY);
         // Error indicator is set if there is no exact match.
         if (tupleIndex == slotManager.getErrorIndicator() || tupleIndex == slotManager.getGreatestKeyIndicator()) {
-            throw new BTreeNonExistentKeyException("Trying to delete a tuple with a nonexistent key in leaf node.");
+            throw new TreeIndexNonExistentKeyException("Trying to delete a tuple with a nonexistent key in leaf node.");
         }
         return tupleIndex;
     }
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 689843b..ff94040 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
@@ -33,7 +33,6 @@
 import edu.uci.ics.hyracks.storage.am.btree.api.IBTreeLeafFrame;
 import edu.uci.ics.hyracks.storage.am.btree.api.ITupleAcceptor;
 import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeException;
-import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeNonExistentKeyException;
 import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeNotUpdateableException;
 import edu.uci.ics.hyracks.storage.am.btree.frames.BTreeNSMInteriorFrame;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTreeOpContext.PageValidationInfo;
@@ -53,6 +52,8 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
 import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
 import edu.uci.ics.hyracks.storage.am.common.api.UnsortedInputException;
+import edu.uci.ics.hyracks.storage.am.common.exceptions.TreeIndexDuplicateKeyException;
+import edu.uci.ics.hyracks.storage.am.common.exceptions.TreeIndexNonExistentKeyException;
 import edu.uci.ics.hyracks.storage.am.common.frames.FrameOpSpaceStatus;
 import edu.uci.ics.hyracks.storage.am.common.impls.AbstractTreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
@@ -562,7 +563,7 @@
         // This means that there could be underflow, even an empty page that is
         // pointed to by an interior node.
         if (ctx.leafFrame.getTupleCount() == 0) {
-            throw new BTreeNonExistentKeyException("Trying to delete a tuple with a nonexistent key in leaf node.");
+            throw new TreeIndexNonExistentKeyException("Trying to delete a tuple with a nonexistent key in leaf node.");
         }
         int tupleIndex = ctx.leafFrame.findDeleteTupleIndex(tuple);
         ITupleReference beforeTuple = ctx.leafFrame.getMatchingKeyTuple(tuple, tupleIndex);
@@ -1024,9 +1025,12 @@
         protected void verifyInputTuple(ITupleReference tuple, ITupleReference prevTuple) throws IndexException,
                 HyracksDataException {
             // New tuple should be strictly greater than last tuple.
-            if (cmp.compare(tuple, prevTuple) <= 0) {
-                throw new UnsortedInputException(
-                        "Input stream given to BTree bulk load is not sorted or has duplicates.");
+            int cmpResult = cmp.compare(tuple, prevTuple);
+            if (cmpResult < 0) {
+                throw new UnsortedInputException("Input stream given to BTree bulk load is not sorted.");
+            }
+            if (cmpResult == 0) {
+                throw new TreeIndexDuplicateKeyException("Input stream given to BTree bulk load has duplicates.");
             }
         }
 
diff --git a/hyracks/hyracks-storage-am-common/pom.xml b/hyracks/hyracks-storage-am-common/pom.xml
index 64f2ddb..309f183 100644
--- a/hyracks/hyracks-storage-am-common/pom.xml
+++ b/hyracks/hyracks-storage-am-common/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -41,28 +41,28 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-api</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-common</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-dataflow-common</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-dataflow-std</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
diff --git a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/IndexInsertUpdateDeleteOperatorNodePushable.java b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/IndexInsertUpdateDeleteOperatorNodePushable.java
index 4a9cfb4..092fada 100644
--- a/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/IndexInsertUpdateDeleteOperatorNodePushable.java
+++ b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/IndexInsertUpdateDeleteOperatorNodePushable.java
@@ -30,6 +30,8 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IModificationOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.api.ITupleFilter;
 import edu.uci.ics.hyracks.storage.am.common.api.ITupleFilterFactory;
+import edu.uci.ics.hyracks.storage.am.common.exceptions.TreeIndexDuplicateKeyException;
+import edu.uci.ics.hyracks.storage.am.common.exceptions.TreeIndexNonExistentKeyException;
 import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.IndexOperation;
 import edu.uci.ics.hyracks.storage.am.common.tuples.PermutingFrameTupleReference;
@@ -97,7 +99,11 @@
 
                 switch (op) {
                     case INSERT: {
-                        indexAccessor.insert(tuple);
+                        try {
+                            indexAccessor.insert(tuple);
+                        } catch (TreeIndexDuplicateKeyException e) {
+                            // ingnore that exception to allow inserting existing keys which becomes an NoOp
+                        }
                         break;
                     }
                     case UPDATE: {
@@ -109,7 +115,11 @@
                         break;
                     }
                     case DELETE: {
-                        indexAccessor.delete(tuple);
+                        try {
+                            indexAccessor.delete(tuple);
+                        } catch (TreeIndexNonExistentKeyException e) {
+                            // ingnore that exception to allow deletions of non-existing keys
+                        }
                         break;
                     }
                     default: {
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/exceptions/TreeIndexDuplicateKeyException.java
similarity index 70%
rename from hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
rename to hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/exceptions/TreeIndexDuplicateKeyException.java
index cde5022..1767504 100644
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
+++ b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/exceptions/TreeIndexDuplicateKeyException.java
@@ -13,16 +13,18 @@
  * limitations under the License.
  */
 
-package edu.uci.ics.hyracks.storage.am.btree.exceptions;
+package edu.uci.ics.hyracks.storage.am.common.exceptions;
 
-public class BTreeDuplicateKeyException extends BTreeException {
+import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
+
+public class TreeIndexDuplicateKeyException extends TreeIndexException {
     private static final long serialVersionUID = 1L;
 
-    public BTreeDuplicateKeyException(Exception e) {
+    public TreeIndexDuplicateKeyException(Exception e) {
         super(e);
     }
 
-    public BTreeDuplicateKeyException(String message) {
+    public TreeIndexDuplicateKeyException(String message) {
         super(message);
     }
 }
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/exceptions/TreeIndexNonExistentKeyException.java
similarity index 61%
copy from hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
copy to hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/exceptions/TreeIndexNonExistentKeyException.java
index cde5022..8b62063 100644
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
+++ b/hyracks/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/exceptions/TreeIndexNonExistentKeyException.java
@@ -13,16 +13,19 @@
  * limitations under the License.
  */
 
-package edu.uci.ics.hyracks.storage.am.btree.exceptions;
+package edu.uci.ics.hyracks.storage.am.common.exceptions;
 
-public class BTreeDuplicateKeyException extends BTreeException {
-    private static final long serialVersionUID = 1L;
+import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
 
-    public BTreeDuplicateKeyException(Exception e) {
-        super(e);
-    }
+public class TreeIndexNonExistentKeyException extends TreeIndexException {
 
-    public BTreeDuplicateKeyException(String message) {
-        super(message);
-    }
+	private static final long serialVersionUID = 1L;
+
+	public TreeIndexNonExistentKeyException(Exception e) {
+		super(e);
+	}
+
+	public TreeIndexNonExistentKeyException(String message) {
+		super(message);
+	}
 }
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 19d40a0..a85a174 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
@@ -12,352 +12,356 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
-package edu.uci.ics.hyracks.storage.am.common.impls;
-
-import java.util.ArrayList;
-
-import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
-import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
-import edu.uci.ics.hyracks.api.io.FileReference;
-import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
-import edu.uci.ics.hyracks.storage.am.common.api.IFreePageManager;
-import edu.uci.ics.hyracks.storage.am.common.api.IIndexBulkLoader;
-import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
-import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexAccessor;
-import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexFrame;
-import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexFrameFactory;
-import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexMetaDataFrame;
-import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexTupleWriter;
-import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
-import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
-import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
-import edu.uci.ics.hyracks.storage.common.buffercache.IBufferCache;
-import edu.uci.ics.hyracks.storage.common.buffercache.ICachedPage;
-import edu.uci.ics.hyracks.storage.common.file.BufferedFileHandle;
-import edu.uci.ics.hyracks.storage.common.file.IFileMapProvider;
-
-public abstract class AbstractTreeIndex implements ITreeIndex {
-
-    protected final static int rootPage = 1;
-
-    protected final IBufferCache bufferCache;
-    protected final IFileMapProvider fileMapProvider;
-    protected final IFreePageManager freePageManager;
-
-    protected final ITreeIndexFrameFactory interiorFrameFactory;
-    protected final ITreeIndexFrameFactory leafFrameFactory;
-
-    protected final IBinaryComparatorFactory[] cmpFactories;
-    protected final int fieldCount;
-
-    protected FileReference file;
-    protected int fileId = -1;
-
-    private boolean isActivated = false;
-
-    public AbstractTreeIndex(IBufferCache bufferCache, IFileMapProvider fileMapProvider,
-            IFreePageManager freePageManager, ITreeIndexFrameFactory interiorFrameFactory,
-            ITreeIndexFrameFactory leafFrameFactory, IBinaryComparatorFactory[] cmpFactories, int fieldCount,
-            FileReference file) {
-        this.bufferCache = bufferCache;
-        this.fileMapProvider = fileMapProvider;
-        this.freePageManager = freePageManager;
-        this.interiorFrameFactory = interiorFrameFactory;
-        this.leafFrameFactory = leafFrameFactory;
-        this.cmpFactories = cmpFactories;
-        this.fieldCount = fieldCount;
-        this.file = file;
-    }
-
-    public synchronized void create() throws HyracksDataException {
-        if (isActivated) {
-            throw new HyracksDataException("Failed to create the index since it is activated.");
-        }
-
-        boolean fileIsMapped = false;
-        synchronized (fileMapProvider) {
-            fileIsMapped = fileMapProvider.isMapped(file);
-            if (!fileIsMapped) {
-                bufferCache.createFile(file);
-            }
-            fileId = fileMapProvider.lookupFileId(file);
-            try {
-                // Also creates the file if it doesn't exist yet.
-                bufferCache.openFile(fileId);
-            } catch (HyracksDataException e) {
-                // Revert state of buffer cache since file failed to open.
-                if (!fileIsMapped) {
-                    bufferCache.deleteFile(fileId, false);
-                }
-                throw e;
-            }
-        }
-
-        freePageManager.open(fileId);
-        initEmptyTree();
-        freePageManager.close();
-        bufferCache.closeFile(fileId);
-    }
-
-    private void initEmptyTree() throws HyracksDataException {
-        ITreeIndexFrame frame = leafFrameFactory.createFrame();
-        ITreeIndexMetaDataFrame metaFrame = freePageManager.getMetaDataFrameFactory().createFrame();
-        freePageManager.init(metaFrame, rootPage);
-
-        ICachedPage rootNode = bufferCache.pin(BufferedFileHandle.getDiskPageId(fileId, rootPage), true);
-        rootNode.acquireWriteLatch();
-        try {
-            frame.setPage(rootNode);
-            frame.initBuffer((byte) 0);
-        } finally {
-            rootNode.releaseWriteLatch();
-            bufferCache.unpin(rootNode);
-        }
-    }
-
-    public synchronized void activate() throws HyracksDataException {
-        if (isActivated) {
-            throw new HyracksDataException("Failed to activate the index since it is already activated.");
-        }
-
-        boolean fileIsMapped = false;
-        synchronized (fileMapProvider) {
-            fileIsMapped = fileMapProvider.isMapped(file);
-            if (!fileIsMapped) {
-                bufferCache.createFile(file);
-            }
-            fileId = fileMapProvider.lookupFileId(file);
-            try {
-                // Also creates the file if it doesn't exist yet.
-                bufferCache.openFile(fileId);
-            } catch (HyracksDataException e) {
-                // Revert state of buffer cache since file failed to open.
-                if (!fileIsMapped) {
-                    bufferCache.deleteFile(fileId, false);
-                }
-                throw e;
-            }
-        }
-        freePageManager.open(fileId);
-
-        // TODO: Should probably have some way to check that the tree is physically consistent
-        // or that the file we just opened actually is a tree
-
-        isActivated = true;
-    }
-
-    public synchronized void deactivate() throws HyracksDataException {
-        if (!isActivated) {
-            throw new HyracksDataException("Failed to deactivate the index since it is already deactivated.");
-        }
-
-        bufferCache.closeFile(fileId);
-        freePageManager.close();
-
-        isActivated = false;
-    }
-
-    public synchronized void destroy() throws HyracksDataException {
-        if (isActivated) {
-            throw new HyracksDataException("Failed to destroy the index since it is activated.");
-        }
-
-        file.delete();
-        if (fileId == -1) {
-            return;
-        }
-
-        bufferCache.deleteFile(fileId, false);
-        fileId = -1;
-    }
-
-    public synchronized void clear() throws HyracksDataException {
-        if (!isActivated) {
-            throw new HyracksDataException("Failed to clear the index since it is not activated.");
-        }
-        initEmptyTree();
-    }
-
-    public boolean isEmptyTree(ITreeIndexFrame frame) throws HyracksDataException {
-        ICachedPage rootNode = bufferCache.pin(BufferedFileHandle.getDiskPageId(fileId, rootPage), false);
-        rootNode.acquireReadLatch();
-        try {
-            frame.setPage(rootNode);
-            if (frame.getLevel() == 0 && frame.getTupleCount() == 0) {
-                return true;
-            } else {
-                return false;
-            }
-        } finally {
-            rootNode.releaseReadLatch();
-            bufferCache.unpin(rootNode);
-        }
-    }
-
-    public byte getTreeHeight(ITreeIndexFrame frame) throws HyracksDataException {
-        ICachedPage rootNode = bufferCache.pin(BufferedFileHandle.getDiskPageId(fileId, rootPage), false);
-        rootNode.acquireReadLatch();
-        try {
-            frame.setPage(rootNode);
-            return frame.getLevel();
-        } finally {
-            rootNode.releaseReadLatch();
-            bufferCache.unpin(rootNode);
-        }
-    }
-
-    public int getFileId() {
-        return fileId;
-    }
-
-    public FileReference getFileReference() {
-        return file;
-    }
-
-    public IBufferCache getBufferCache() {
-        return bufferCache;
-    }
-
-    public ITreeIndexFrameFactory getInteriorFrameFactory() {
-        return interiorFrameFactory;
-    }
-
-    public ITreeIndexFrameFactory getLeafFrameFactory() {
-        return leafFrameFactory;
-    }
-
-    public IBinaryComparatorFactory[] getComparatorFactories() {
-        return cmpFactories;
-    }
-
-    public IFreePageManager getFreePageManager() {
-        return freePageManager;
-    }
-
-    public int getRootPageId() {
-        return rootPage;
-    }
-
-    public int getFieldCount() {
-        return fieldCount;
-    }
-
-    public abstract class AbstractTreeIndexBulkLoader implements IIndexBulkLoader {
-        protected final MultiComparator cmp;
-        protected final int slotSize;
-        protected final int leafMaxBytes;
-        protected final int interiorMaxBytes;
-        protected final ArrayList<NodeFrontier> nodeFrontiers = new ArrayList<NodeFrontier>();
-        protected final ITreeIndexMetaDataFrame metaFrame;
-        protected final ITreeIndexTupleWriter tupleWriter;
-        protected ITreeIndexFrame leafFrame;
-        protected ITreeIndexFrame interiorFrame;
-
-        public AbstractTreeIndexBulkLoader(float fillFactor) throws TreeIndexException, HyracksDataException {
-            leafFrame = leafFrameFactory.createFrame();
-            interiorFrame = interiorFrameFactory.createFrame();
-            metaFrame = freePageManager.getMetaDataFrameFactory().createFrame();
-
-            if (!isEmptyTree(leafFrame)) {
-                throw new TreeIndexException("Cannot bulk-load a non-empty tree.");
-            }
-
-            this.cmp = MultiComparator.createIgnoreFieldLength(cmpFactories);
-
-            leafFrame.setMultiComparator(cmp);
-            interiorFrame.setMultiComparator(cmp);
-
-            tupleWriter = leafFrame.getTupleWriter();
-
-            NodeFrontier leafFrontier = new NodeFrontier(leafFrame.createTupleReference());
-            leafFrontier.pageId = freePageManager.getFreePage(metaFrame);
-            leafFrontier.page = bufferCache.pin(BufferedFileHandle.getDiskPageId(fileId, leafFrontier.pageId), true);
-            leafFrontier.page.acquireWriteLatch();
-
-            interiorFrame.setPage(leafFrontier.page);
-            interiorFrame.initBuffer((byte) 0);
-            interiorMaxBytes = (int) ((float) interiorFrame.getBuffer().capacity() * fillFactor);
-
-            leafFrame.setPage(leafFrontier.page);
-            leafFrame.initBuffer((byte) 0);
-            leafMaxBytes = (int) ((float) leafFrame.getBuffer().capacity() * fillFactor);
-            slotSize = leafFrame.getSlotSize();
-
-            nodeFrontiers.add(leafFrontier);
-        }
-
-        public abstract void add(ITupleReference tuple) throws IndexException, HyracksDataException;
-
-        protected void handleException() throws HyracksDataException {
-            // Unlatch and unpin pages.
-            for (NodeFrontier nodeFrontier : nodeFrontiers) {
-                nodeFrontier.page.releaseWriteLatch();
-                bufferCache.unpin(nodeFrontier.page);
-            }
-        }
-
-        @Override
-        public void end() throws HyracksDataException {
-            // copy the root generated from the bulk-load to *the* root page location
-            ICachedPage newRoot = bufferCache.pin(BufferedFileHandle.getDiskPageId(fileId, rootPage), true);
-            newRoot.acquireWriteLatch();
-            NodeFrontier lastNodeFrontier = nodeFrontiers.get(nodeFrontiers.size() - 1);
-            try {
-                System.arraycopy(lastNodeFrontier.page.getBuffer().array(), 0, newRoot.getBuffer().array(), 0,
-                        lastNodeFrontier.page.getBuffer().capacity());
-            } finally {
-                newRoot.releaseWriteLatch();
-                bufferCache.unpin(newRoot);
-
-                // register old root as a free page
-                freePageManager.addFreePage(metaFrame, lastNodeFrontier.pageId);
-
-                for (int i = 0; i < nodeFrontiers.size(); i++) {
-                    nodeFrontiers.get(i).page.releaseWriteLatch();
-                    bufferCache.unpin(nodeFrontiers.get(i).page);
-                }
-            }
-        }
-
-        protected void addLevel() throws HyracksDataException {
-            NodeFrontier frontier = new NodeFrontier(tupleWriter.createTupleReference());
-            frontier.pageId = freePageManager.getFreePage(metaFrame);
-            frontier.page = bufferCache.pin(BufferedFileHandle.getDiskPageId(fileId, frontier.pageId), true);
-            frontier.page.acquireWriteLatch();
-            frontier.lastTuple.setFieldCount(cmp.getKeyFieldCount());
-            interiorFrame.setPage(frontier.page);
-            interiorFrame.initBuffer((byte) nodeFrontiers.size());
-            nodeFrontiers.add(frontier);
-        }
-    }
-
-    public class TreeIndexInsertBulkLoader implements IIndexBulkLoader {
-        ITreeIndexAccessor accessor;
-
-        public TreeIndexInsertBulkLoader() throws HyracksDataException {
-            accessor = (ITreeIndexAccessor) createAccessor(NoOpOperationCallback.INSTANCE,
-                    NoOpOperationCallback.INSTANCE);
-        }
-
-        @Override
-        public void add(ITupleReference tuple) throws HyracksDataException {
-            try {
-                accessor.insert(tuple);
-            } catch (IndexException e) {
-                throw new HyracksDataException(e);
-            }
-        }
-
-        @Override
-        public void end() throws HyracksDataException {
-            // do nothing
-        }
-
-    }
-
-    @Override
-    public long getMemoryAllocationSize() {
-        return 0;
-    }
+
+package edu.uci.ics.hyracks.storage.am.common.impls;
+
+import java.util.ArrayList;
+
+import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
+import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+import edu.uci.ics.hyracks.api.io.FileReference;
+import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
+import edu.uci.ics.hyracks.storage.am.common.api.IFreePageManager;
+import edu.uci.ics.hyracks.storage.am.common.api.IIndexBulkLoader;
+import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
+import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexAccessor;
+import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexFrame;
+import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexFrameFactory;
+import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexMetaDataFrame;
+import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexTupleWriter;
+import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
+import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
+import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
+import edu.uci.ics.hyracks.storage.common.buffercache.IBufferCache;
+import edu.uci.ics.hyracks.storage.common.buffercache.ICachedPage;
+import edu.uci.ics.hyracks.storage.common.file.BufferedFileHandle;
+import edu.uci.ics.hyracks.storage.common.file.IFileMapProvider;
+
+public abstract class AbstractTreeIndex implements ITreeIndex {
+
+    protected final static int rootPage = 1;
+
+    protected final IBufferCache bufferCache;
+    protected final IFileMapProvider fileMapProvider;
+    protected final IFreePageManager freePageManager;
+
+    protected final ITreeIndexFrameFactory interiorFrameFactory;
+    protected final ITreeIndexFrameFactory leafFrameFactory;
+
+    protected final IBinaryComparatorFactory[] cmpFactories;
+    protected final int fieldCount;
+
+    protected FileReference file;
+    protected int fileId = -1;
+
+    private boolean isActivated = false;
+
+    public AbstractTreeIndex(IBufferCache bufferCache, IFileMapProvider fileMapProvider,
+            IFreePageManager freePageManager, ITreeIndexFrameFactory interiorFrameFactory,
+            ITreeIndexFrameFactory leafFrameFactory, IBinaryComparatorFactory[] cmpFactories, int fieldCount,
+            FileReference file) {
+        this.bufferCache = bufferCache;
+        this.fileMapProvider = fileMapProvider;
+        this.freePageManager = freePageManager;
+        this.interiorFrameFactory = interiorFrameFactory;
+        this.leafFrameFactory = leafFrameFactory;
+        this.cmpFactories = cmpFactories;
+        this.fieldCount = fieldCount;
+        this.file = file;
+    }
+
+    public synchronized void create() throws HyracksDataException {
+        if (isActivated) {
+            throw new HyracksDataException("Failed to create the index since it is activated.");
+        }
+
+        boolean fileIsMapped = false;
+        synchronized (fileMapProvider) {
+            fileIsMapped = fileMapProvider.isMapped(file);
+            if (!fileIsMapped) {
+                bufferCache.createFile(file);
+            }
+            fileId = fileMapProvider.lookupFileId(file);
+            try {
+                // Also creates the file if it doesn't exist yet.
+                bufferCache.openFile(fileId);
+            } catch (HyracksDataException e) {
+                // Revert state of buffer cache since file failed to open.
+                if (!fileIsMapped) {
+                    bufferCache.deleteFile(fileId, false);
+                }
+                throw e;
+            }
+        }
+
+        freePageManager.open(fileId);
+        initEmptyTree();
+        freePageManager.close();
+        bufferCache.closeFile(fileId);
+    }
+
+    private void initEmptyTree() throws HyracksDataException {
+        ITreeIndexFrame frame = leafFrameFactory.createFrame();
+        ITreeIndexMetaDataFrame metaFrame = freePageManager.getMetaDataFrameFactory().createFrame();
+        freePageManager.init(metaFrame, rootPage);
+
+        ICachedPage rootNode = bufferCache.pin(BufferedFileHandle.getDiskPageId(fileId, rootPage), true);
+        rootNode.acquireWriteLatch();
+        try {
+            frame.setPage(rootNode);
+            frame.initBuffer((byte) 0);
+        } finally {
+            rootNode.releaseWriteLatch();
+            bufferCache.unpin(rootNode);
+        }
+    }
+
+    public synchronized void activate() throws HyracksDataException {
+        if (isActivated) {
+            throw new HyracksDataException("Failed to activate the index since it is already activated.");
+        }
+
+        boolean fileIsMapped = false;
+        synchronized (fileMapProvider) {
+            fileIsMapped = fileMapProvider.isMapped(file);
+            if (!fileIsMapped) {
+                bufferCache.createFile(file);
+            }
+            fileId = fileMapProvider.lookupFileId(file);
+            try {
+                // Also creates the file if it doesn't exist yet.
+                bufferCache.openFile(fileId);
+            } catch (HyracksDataException e) {
+                // Revert state of buffer cache since file failed to open.
+                if (!fileIsMapped) {
+                    bufferCache.deleteFile(fileId, false);
+                }
+                throw e;
+            }
+        }
+        freePageManager.open(fileId);
+
+        // TODO: Should probably have some way to check that the tree is physically consistent
+        // or that the file we just opened actually is a tree
+
+        isActivated = true;
+    }
+
+    public synchronized void deactivate() throws HyracksDataException {
+        if (!isActivated) {
+            throw new HyracksDataException("Failed to deactivate the index since it is already deactivated.");
+        }
+
+        bufferCache.closeFile(fileId);
+        freePageManager.close();
+
+        isActivated = false;
+    }
+
+    public synchronized void destroy() throws HyracksDataException {
+        if (isActivated) {
+            throw new HyracksDataException("Failed to destroy the index since it is activated.");
+        }
+
+        file.delete();
+        if (fileId == -1) {
+            return;
+        }
+
+        bufferCache.deleteFile(fileId, false);
+        fileId = -1;
+    }
+
+    public synchronized void clear() throws HyracksDataException {
+        if (!isActivated) {
+            throw new HyracksDataException("Failed to clear the index since it is not activated.");
+        }
+        initEmptyTree();
+    }
+
+    public boolean isEmptyTree(ITreeIndexFrame frame) throws HyracksDataException {
+        ICachedPage rootNode = bufferCache.pin(BufferedFileHandle.getDiskPageId(fileId, rootPage), false);
+        rootNode.acquireReadLatch();
+        try {
+            frame.setPage(rootNode);
+            if (frame.getLevel() == 0 && frame.getTupleCount() == 0) {
+                return true;
+            } else {
+                return false;
+            }
+        } finally {
+            rootNode.releaseReadLatch();
+            bufferCache.unpin(rootNode);
+        }
+    }
+
+    public byte getTreeHeight(ITreeIndexFrame frame) throws HyracksDataException {
+        ICachedPage rootNode = bufferCache.pin(BufferedFileHandle.getDiskPageId(fileId, rootPage), false);
+        rootNode.acquireReadLatch();
+        try {
+            frame.setPage(rootNode);
+            return frame.getLevel();
+        } finally {
+            rootNode.releaseReadLatch();
+            bufferCache.unpin(rootNode);
+        }
+    }
+
+    public int getFileId() {
+        return fileId;
+    }
+
+    public FileReference getFileReference() {
+        return file;
+    }
+
+    public IBufferCache getBufferCache() {
+        return bufferCache;
+    }
+
+    public ITreeIndexFrameFactory getInteriorFrameFactory() {
+        return interiorFrameFactory;
+    }
+
+    public ITreeIndexFrameFactory getLeafFrameFactory() {
+        return leafFrameFactory;
+    }
+
+    public IBinaryComparatorFactory[] getComparatorFactories() {
+        return cmpFactories;
+    }
+
+    public IFreePageManager getFreePageManager() {
+        return freePageManager;
+    }
+
+    public int getRootPageId() {
+        return rootPage;
+    }
+
+    public int getFieldCount() {
+        return fieldCount;
+    }
+
+    public abstract class AbstractTreeIndexBulkLoader implements IIndexBulkLoader {
+        protected final MultiComparator cmp;
+        protected final int slotSize;
+        protected final int leafMaxBytes;
+        protected final int interiorMaxBytes;
+        protected final ArrayList<NodeFrontier> nodeFrontiers = new ArrayList<NodeFrontier>();
+        protected final ITreeIndexMetaDataFrame metaFrame;
+        protected final ITreeIndexTupleWriter tupleWriter;
+        protected ITreeIndexFrame leafFrame;
+        protected ITreeIndexFrame interiorFrame;
+        private boolean releasedLatches;
+
+        public AbstractTreeIndexBulkLoader(float fillFactor) throws TreeIndexException, HyracksDataException {
+            leafFrame = leafFrameFactory.createFrame();
+            interiorFrame = interiorFrameFactory.createFrame();
+            metaFrame = freePageManager.getMetaDataFrameFactory().createFrame();
+
+            if (!isEmptyTree(leafFrame)) {
+                throw new TreeIndexException("Cannot bulk-load a non-empty tree.");
+            }
+
+            this.cmp = MultiComparator.createIgnoreFieldLength(cmpFactories);
+
+            leafFrame.setMultiComparator(cmp);
+            interiorFrame.setMultiComparator(cmp);
+
+            tupleWriter = leafFrame.getTupleWriter();
+
+            NodeFrontier leafFrontier = new NodeFrontier(leafFrame.createTupleReference());
+            leafFrontier.pageId = freePageManager.getFreePage(metaFrame);
+            leafFrontier.page = bufferCache.pin(BufferedFileHandle.getDiskPageId(fileId, leafFrontier.pageId), true);
+            leafFrontier.page.acquireWriteLatch();
+
+            interiorFrame.setPage(leafFrontier.page);
+            interiorFrame.initBuffer((byte) 0);
+            interiorMaxBytes = (int) ((float) interiorFrame.getBuffer().capacity() * fillFactor);
+
+            leafFrame.setPage(leafFrontier.page);
+            leafFrame.initBuffer((byte) 0);
+            leafMaxBytes = (int) ((float) leafFrame.getBuffer().capacity() * fillFactor);
+            slotSize = leafFrame.getSlotSize();
+
+            nodeFrontiers.add(leafFrontier);
+        }
+
+        public abstract void add(ITupleReference tuple) throws IndexException, HyracksDataException;
+
+        protected void handleException() throws HyracksDataException {
+            // Unlatch and unpin pages.
+            for (NodeFrontier nodeFrontier : nodeFrontiers) {
+                nodeFrontier.page.releaseWriteLatch();
+                bufferCache.unpin(nodeFrontier.page);
+            }
+            releasedLatches = true;
+        }
+
+        @Override
+        public void end() throws HyracksDataException {
+            // copy the root generated from the bulk-load to *the* root page location
+            ICachedPage newRoot = bufferCache.pin(BufferedFileHandle.getDiskPageId(fileId, rootPage), true);
+            newRoot.acquireWriteLatch();
+            NodeFrontier lastNodeFrontier = nodeFrontiers.get(nodeFrontiers.size() - 1);
+            try {
+                System.arraycopy(lastNodeFrontier.page.getBuffer().array(), 0, newRoot.getBuffer().array(), 0,
+                        lastNodeFrontier.page.getBuffer().capacity());
+            } finally {
+                newRoot.releaseWriteLatch();
+                bufferCache.unpin(newRoot);
+
+                // register old root as a free page
+                freePageManager.addFreePage(metaFrame, lastNodeFrontier.pageId);
+
+                if (!releasedLatches) {
+                    for (int i = 0; i < nodeFrontiers.size(); i++) {
+                        nodeFrontiers.get(i).page.releaseWriteLatch();
+                        bufferCache.unpin(nodeFrontiers.get(i).page);
+                    }
+                }
+            }
+        }
+
+        protected void addLevel() throws HyracksDataException {
+            NodeFrontier frontier = new NodeFrontier(tupleWriter.createTupleReference());
+            frontier.pageId = freePageManager.getFreePage(metaFrame);
+            frontier.page = bufferCache.pin(BufferedFileHandle.getDiskPageId(fileId, frontier.pageId), true);
+            frontier.page.acquireWriteLatch();
+            frontier.lastTuple.setFieldCount(cmp.getKeyFieldCount());
+            interiorFrame.setPage(frontier.page);
+            interiorFrame.initBuffer((byte) nodeFrontiers.size());
+            nodeFrontiers.add(frontier);
+        }
+    }
+
+    public class TreeIndexInsertBulkLoader implements IIndexBulkLoader {
+        ITreeIndexAccessor accessor;
+
+        public TreeIndexInsertBulkLoader() throws HyracksDataException {
+            accessor = (ITreeIndexAccessor) createAccessor(NoOpOperationCallback.INSTANCE,
+                    NoOpOperationCallback.INSTANCE);
+        }
+
+        @Override
+        public void add(ITupleReference tuple) throws HyracksDataException {
+            try {
+                accessor.insert(tuple);
+            } catch (IndexException e) {
+                throw new HyracksDataException(e);
+            }
+        }
+
+        @Override
+        public void end() throws HyracksDataException {
+            // do nothing
+        }
+
+    }
+
+    @Override
+    public long getMemoryAllocationSize() {
+        return 0;
+    }
 }
diff --git a/hyracks/hyracks-storage-am-lsm-btree/pom.xml b/hyracks/hyracks-storage-am-lsm-btree/pom.xml
index be582e85..d18210e 100644
--- a/hyracks/hyracks-storage-am-lsm-btree/pom.xml
+++ b/hyracks/hyracks-storage-am-lsm-btree/pom.xml
@@ -19,7 +19,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -39,21 +39,21 @@
     <dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-btree</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency> 
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-bloomfilter</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency> 
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-lsm-common</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>  	
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 3557d73..59af99e 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
@@ -27,7 +27,6 @@
 import edu.uci.ics.hyracks.storage.am.bloomfilter.impls.BloomFilter;
 import edu.uci.ics.hyracks.storage.am.bloomfilter.impls.BloomFilterFactory;
 import edu.uci.ics.hyracks.storage.am.bloomfilter.impls.BloomFilterSpecification;
-import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeDuplicateKeyException;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTree;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTree.BTreeAccessor;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTree.BTreeBulkLoader;
@@ -46,6 +45,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexFrameFactory;
 import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
 import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
+import edu.uci.ics.hyracks.storage.am.common.exceptions.TreeIndexDuplicateKeyException;
 import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.IndexOperation;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
@@ -279,7 +279,7 @@
                 memCursor.next();
                 LSMBTreeTupleReference lsmbtreeTuple = (LSMBTreeTupleReference) memCursor.getTuple();
                 if (!lsmbtreeTuple.isAntimatter()) {
-                    throw new BTreeDuplicateKeyException("Failed to insert key since key already exists.");
+                    throw new TreeIndexDuplicateKeyException("Failed to insert key since key already exists.");
                 } else {
                     memCursor.close();
                     ctx.memBTreeAccessor.upsertIfConditionElseInsert(tuple, AntimatterAwareTupleAcceptor.INSTANCE);
@@ -299,7 +299,7 @@
         search(ctx, searchCursor, predicate);
         try {
             if (searchCursor.hasNext()) {
-                throw new BTreeDuplicateKeyException("Failed to insert key since key already exists.");
+                throw new TreeIndexDuplicateKeyException("Failed to insert key since key already exists.");
             }
         } finally {
             searchCursor.close();
diff --git a/hyracks/hyracks-storage-am-lsm-common/pom.xml b/hyracks/hyracks-storage-am-lsm-common/pom.xml
index 51ce0dd..4a6fe50 100644
--- a/hyracks/hyracks-storage-am-lsm-common/pom.xml
+++ b/hyracks/hyracks-storage-am-lsm-common/pom.xml
@@ -19,7 +19,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -39,21 +39,21 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-common</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-bloomfilter</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<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>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>  	
diff --git a/hyracks/hyracks-storage-am-lsm-invertedindex/pom.xml b/hyracks/hyracks-storage-am-lsm-invertedindex/pom.xml
index 6891047..9e5e91c 100644
--- a/hyracks/hyracks-storage-am-lsm-invertedindex/pom.xml
+++ b/hyracks/hyracks-storage-am-lsm-invertedindex/pom.xml
@@ -19,7 +19,7 @@
 	<parent>
 		<artifactId>hyracks</artifactId>
 		<groupId>edu.uci.ics.hyracks</groupId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 		<relativePath>..</relativePath>
 	</parent>
 
@@ -40,14 +40,14 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-storage-am-btree</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-storage-am-lsm-common</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 	    </dependency>
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 3eae5a7..244dfa0 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
@@ -27,7 +27,6 @@
 import edu.uci.ics.hyracks.storage.am.bloomfilter.impls.BloomCalculations;
 import edu.uci.ics.hyracks.storage.am.bloomfilter.impls.BloomFilterFactory;
 import edu.uci.ics.hyracks.storage.am.bloomfilter.impls.BloomFilterSpecification;
-import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeDuplicateKeyException;
 import edu.uci.ics.hyracks.storage.am.btree.frames.BTreeLeafFrameType;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTree;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTree.BTreeAccessor;
@@ -43,6 +42,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.ISearchPredicate;
 import edu.uci.ics.hyracks.storage.am.common.api.IVirtualFreePageManager;
 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.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.IndexOperation;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
@@ -305,7 +305,7 @@
                 ctx.keysOnlyTuple.reset(tuple);
                 try {
                     ctx.deletedKeysBTreeAccessor.insert(ctx.keysOnlyTuple);
-                } catch (BTreeDuplicateKeyException e) {
+                } catch (TreeIndexDuplicateKeyException e) {
                     // Key has already been deleted.
                 }
                 break;
diff --git a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/InMemoryInvertedIndex.java b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/InMemoryInvertedIndex.java
index 222f4de..c70c2d5 100644
--- a/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/InMemoryInvertedIndex.java
+++ b/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/InMemoryInvertedIndex.java
@@ -19,9 +19,7 @@
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.api.io.FileReference;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
-import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeDuplicateKeyException;
 import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeException;
-import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeNonExistentKeyException;
 import edu.uci.ics.hyracks.storage.am.btree.frames.BTreeLeafFrameType;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTree;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTree.BTreeAccessor;
@@ -33,6 +31,8 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IModificationOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.api.ISearchOperationCallback;
 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.exceptions.TreeIndexNonExistentKeyException;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.IndexOperation;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.IVirtualBufferCache;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedIndex;
@@ -117,7 +117,7 @@
             ITupleReference insertTuple = ctx.tupleIter.getTuple();
             try {
                 btreeAccessor.insert(insertTuple);
-            } catch (BTreeDuplicateKeyException e) {
+            } catch (TreeIndexDuplicateKeyException e) {
                 // This exception may be caused by duplicate tokens in the same insert "document".
                 // We ignore such duplicate tokens in all inverted-index implementations, hence
                 // we can safely ignore this exception.
@@ -134,7 +134,7 @@
             ITupleReference deleteTuple = ctx.tupleIter.getTuple();
             try {
                 btreeAccessor.delete(deleteTuple);
-            } catch (BTreeNonExistentKeyException e) {
+            } catch (TreeIndexNonExistentKeyException e) {
                 // Ignore this exception, since a document may have duplicate tokens.
             }
         }
diff --git a/hyracks/hyracks-storage-am-lsm-rtree/pom.xml b/hyracks/hyracks-storage-am-lsm-rtree/pom.xml
index 99c9b17..09a7fbf 100644
--- a/hyracks/hyracks-storage-am-lsm-rtree/pom.xml
+++ b/hyracks/hyracks-storage-am-lsm-rtree/pom.xml
@@ -19,7 +19,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -39,21 +39,21 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-lsm-common</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<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>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-rtree</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>  		
diff --git a/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/AbstractLSMRTree.java b/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/AbstractLSMRTree.java
index e3e690b..285010c 100644
--- a/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/AbstractLSMRTree.java
+++ b/hyracks/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/AbstractLSMRTree.java
@@ -23,8 +23,6 @@
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.api.io.FileReference;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
-import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeDuplicateKeyException;
-import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeNonExistentKeyException;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTree;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTree.BTreeAccessor;
 import edu.uci.ics.hyracks.storage.am.btree.impls.RangePredicate;
@@ -36,6 +34,8 @@
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexFrameFactory;
 import edu.uci.ics.hyracks.storage.am.common.api.IVirtualFreePageManager;
 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.exceptions.TreeIndexNonExistentKeyException;
 import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.IndexOperation;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMComponent;
@@ -306,7 +306,7 @@
             if (foundTupleInMemoryBTree) {
                 try {
                     ctx.memBTreeAccessor.delete(tuple);
-                } catch (BTreeNonExistentKeyException e) {
+                } catch (TreeIndexNonExistentKeyException e) {
                     // Tuple has been deleted in the meantime. Do nothing.
                     // This normally shouldn't happen if we are dealing with
                     // good citizens since LSMRTree is used as a secondary
@@ -320,7 +320,7 @@
         } else {
             try {
                 ctx.memBTreeAccessor.insert(tuple);
-            } catch (BTreeDuplicateKeyException e) {
+            } catch (TreeIndexDuplicateKeyException e) {
                 // Do nothing, because one delete tuple is enough to indicate
                 // that all the corresponding insert tuples are deleted
             }
diff --git a/hyracks/hyracks-storage-am-rtree/pom.xml b/hyracks/hyracks-storage-am-rtree/pom.xml
index fdc3d3c..410ed6f 100644
--- a/hyracks/hyracks-storage-am-rtree/pom.xml
+++ b/hyracks/hyracks-storage-am-rtree/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -41,21 +41,21 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-common</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-dataflow-common</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-dataflow-std</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
diff --git a/hyracks/hyracks-storage-common/pom.xml b/hyracks/hyracks-storage-common/pom.xml
index ed8e88c..349c223 100644
--- a/hyracks/hyracks-storage-common/pom.xml
+++ b/hyracks/hyracks-storage-common/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -41,7 +41,7 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-api</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
diff --git a/hyracks/hyracks-test-support/pom.xml b/hyracks/hyracks-test-support/pom.xml
index 641611c..d2e1697 100644
--- a/hyracks/hyracks-test-support/pom.xml
+++ b/hyracks/hyracks-test-support/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -41,33 +41,33 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-control-nc</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-common</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-btree</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-rtree</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-lsm-invertedindex</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
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 eafeff2..0a70185 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
@@ -46,6 +46,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexCursor;
 import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
 import edu.uci.ics.hyracks.storage.am.common.api.UnsortedInputException;
+import edu.uci.ics.hyracks.storage.am.common.exceptions.TreeIndexDuplicateKeyException;
 import edu.uci.ics.hyracks.storage.am.common.impls.TreeIndexDiskOrderScanCursor;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
 
@@ -140,9 +141,9 @@
 
     /**
      * This test the btree page split. Originally this test didn't pass since
-     * the btree was spliting by cardinality and not size. Thus, we might end
-     * up with a situation where there is not enough space to insert the new
-     * tuple after the split which will throw an error and the split won't be
+     * the btree was spliting by cardinality and not size. Thus, we might end up
+     * with a situation where there is not enough space to insert the new tuple
+     * after the split which will throw an error and the split won't be
      * propagated to upper level; thus, the tree is corrupted. Now, it split
      * page by size. The correct behavior on abnormally large keys/values.
      */
@@ -716,6 +717,12 @@
                     }
                     // Success.
                     break;
+                } catch (TreeIndexDuplicateKeyException e2) {
+                    if (j != i) {
+                        fail("Unexpected exception: " + e2.getMessage());
+                    }
+                    // Success.
+                    break;
                 }
             }
 
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 5b7b050..9de217b 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
@@ -35,7 +35,6 @@
 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.dataflow.common.util.TupleUtils;
-import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeDuplicateKeyException;
 import edu.uci.ics.hyracks.storage.am.btree.impls.RangePredicate;
 import edu.uci.ics.hyracks.storage.am.btree.util.BTreeUtils;
 import edu.uci.ics.hyracks.storage.am.common.CheckTuple;
@@ -44,6 +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.exceptions.TreeIndexDuplicateKeyException;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
 
 @SuppressWarnings("rawtypes")
@@ -205,7 +205,7 @@
                 // Set expected values. Do this only after insertion succeeds
                 // because we ignore duplicate keys.
                 ctx.insertCheckTuple(createStringCheckTuple(fieldValues, ctx.getKeyFieldCount()), ctx.getCheckTuples());
-            } catch (BTreeDuplicateKeyException e) {
+            } catch (TreeIndexDuplicateKeyException e) {
                 // Ignore duplicate key insertions.
             }
         }
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-bloomfilter-test/pom.xml b/hyracks/hyracks-tests/hyracks-storage-am-bloomfilter-test/pom.xml
index 213e667..cacd829 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-bloomfilter-test/pom.xml
+++ b/hyracks/hyracks-tests/hyracks-storage-am-bloomfilter-test/pom.xml
@@ -19,7 +19,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-tests</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -46,14 +46,14 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-bloomfilter</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-test-support</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>test</scope>
   	</dependency>
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-btree-test/pom.xml b/hyracks/hyracks-tests/hyracks-storage-am-btree-test/pom.xml
index 9d421a3..6fa8414 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-btree-test/pom.xml
+++ b/hyracks/hyracks-tests/hyracks-storage-am-btree-test/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-tests</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -48,14 +48,14 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-btree</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-test-support</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>test</scope>
   	</dependency>
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 262e21c..22d3e6a 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
@@ -19,8 +19,6 @@
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleReference;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
-import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeDuplicateKeyException;
-import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeNonExistentKeyException;
 import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeNotUpdateableException;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTree;
 import edu.uci.ics.hyracks.storage.am.btree.impls.RangePredicate;
@@ -31,6 +29,8 @@
 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.datagen.DataGenThread;
+import edu.uci.ics.hyracks.storage.am.common.exceptions.TreeIndexDuplicateKeyException;
+import edu.uci.ics.hyracks.storage.am.common.exceptions.TreeIndexNonExistentKeyException;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
 
 public class BTreeTestWorker extends AbstractIndexTestWorker {
@@ -60,7 +60,7 @@
             case INSERT:
                 try {
                     accessor.insert(tuple);
-                } catch (BTreeDuplicateKeyException e) {
+                } catch (TreeIndexDuplicateKeyException e) {
                     // Ignore duplicate keys, since we get random tuples.
                 }
                 break;
@@ -74,7 +74,7 @@
                 deleteTuple.reset(deleteTb.getFieldEndOffsets(), deleteTb.getByteArray());
                 try {
                     accessor.delete(deleteTuple);
-                } catch (BTreeNonExistentKeyException e) {
+                } catch (TreeIndexNonExistentKeyException e) {
                     // Ignore non-existant keys, since we get random tuples.
                 }
                 break;
@@ -82,7 +82,7 @@
             case UPDATE:
                 try {
                     accessor.update(tuple);
-                } catch (BTreeNonExistentKeyException e) {
+                } catch (TreeIndexNonExistentKeyException e) {
                     // Ignore non-existant keys, since we get random tuples.
                 } catch (BTreeNotUpdateableException e) {
                     // Ignore not updateable exception due to numKeys == numFields.
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/pom.xml b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/pom.xml
index bfaebd8..83d382c 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/pom.xml
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/pom.xml
@@ -19,7 +19,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-tests</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -39,20 +39,20 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-lsm-btree</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<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>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-test-support</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   </dependencies>
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 8a37b4e..4a96131 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
@@ -19,8 +19,6 @@
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleReference;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
-import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeDuplicateKeyException;
-import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeNonExistentKeyException;
 import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeNotUpdateableException;
 import edu.uci.ics.hyracks.storage.am.btree.impls.RangePredicate;
 import edu.uci.ics.hyracks.storage.am.common.AbstractIndexTestWorker;
@@ -30,6 +28,8 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexCursor;
 import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
 import edu.uci.ics.hyracks.storage.am.common.datagen.DataGenThread;
+import edu.uci.ics.hyracks.storage.am.common.exceptions.TreeIndexDuplicateKeyException;
+import edu.uci.ics.hyracks.storage.am.common.exceptions.TreeIndexNonExistentKeyException;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
 import edu.uci.ics.hyracks.storage.am.lsm.btree.impls.LSMBTree;
 import edu.uci.ics.hyracks.storage.am.lsm.btree.impls.LSMBTree.LSMBTreeAccessor;
@@ -60,7 +60,7 @@
             case INSERT:
                 try {
                     accessor.insert(tuple);
-                } catch (BTreeDuplicateKeyException e) {
+                } catch (TreeIndexDuplicateKeyException e) {
                     // Ignore duplicate keys, since we get random tuples.
                 }
                 break;
@@ -74,7 +74,7 @@
                 deleteTuple.reset(deleteTb.getFieldEndOffsets(), deleteTb.getByteArray());
                 try {
                     accessor.delete(deleteTuple);
-                } catch (BTreeNonExistentKeyException e) {
+                } catch (TreeIndexNonExistentKeyException e) {
                     // Ignore non-existant keys, since we get random tuples.
                 }
                 break;
@@ -82,7 +82,7 @@
             case UPDATE:
                 try {
                     accessor.update(tuple);
-                } catch (BTreeNonExistentKeyException e) {
+                } catch (TreeIndexNonExistentKeyException e) {
                     // Ignore non-existant keys, since we get random tuples.
                 } catch (BTreeNotUpdateableException e) {
                     // Ignore not updateable exception due to numKeys == numFields.
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-common-test/pom.xml b/hyracks/hyracks-tests/hyracks-storage-am-lsm-common-test/pom.xml
index be98009..7a4dc6f 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-common-test/pom.xml
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-common-test/pom.xml
@@ -19,7 +19,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-tests</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -39,14 +39,14 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-lsm-common</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-test-support</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/pom.xml b/hyracks/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/pom.xml
index 6b08d45..ba3e606 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/pom.xml
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/pom.xml
@@ -19,7 +19,7 @@
 	<parent>
 		<artifactId>hyracks-tests</artifactId>
 		<groupId>edu.uci.ics.hyracks</groupId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 		<relativePath>..</relativePath>
 	</parent>
 
@@ -40,21 +40,21 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-storage-am-lsm-invertedindex</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-test-support</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>test</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-data-std</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>test</scope>
 		</dependency>
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-rtree-test/pom.xml b/hyracks/hyracks-tests/hyracks-storage-am-lsm-rtree-test/pom.xml
index 6b7a973..3d4fece 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-rtree-test/pom.xml
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-rtree-test/pom.xml
@@ -19,7 +19,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-tests</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -39,14 +39,14 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-lsm-rtree</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-test-support</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-rtree-test/pom.xml b/hyracks/hyracks-tests/hyracks-storage-am-rtree-test/pom.xml
index 8c4bf9c..547a3a4 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-rtree-test/pom.xml
+++ b/hyracks/hyracks-tests/hyracks-storage-am-rtree-test/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-tests</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -48,14 +48,14 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-am-rtree</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-test-support</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>test</scope>
   	</dependency>
diff --git a/hyracks/hyracks-tests/hyracks-storage-common-test/pom.xml b/hyracks/hyracks-tests/hyracks-storage-common-test/pom.xml
index 5345396..d9fdc26 100644
--- a/hyracks/hyracks-tests/hyracks-storage-common-test/pom.xml
+++ b/hyracks/hyracks-tests/hyracks-storage-common-test/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks-tests</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <build>
@@ -48,13 +48,13 @@
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-storage-common</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<scope>compile</scope>
   	</dependency>
   	<dependency>
   		<groupId>edu.uci.ics.hyracks</groupId>
   		<artifactId>hyracks-test-support</artifactId>
-  		<version>0.2.9-SNAPSHOT</version>
+  		<version>0.2.10-SNAPSHOT</version>
   		<type>jar</type>
   		<scope>compile</scope>
   	</dependency>
diff --git a/hyracks/hyracks-tests/pom.xml b/hyracks/hyracks-tests/pom.xml
index 9f2e0e1..441b76c 100644
--- a/hyracks/hyracks-tests/pom.xml
+++ b/hyracks/hyracks-tests/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>edu.uci.ics.hyracks</groupId>
     <artifactId>hyracks</artifactId>
-    <version>0.2.9-SNAPSHOT</version>
+    <version>0.2.10-SNAPSHOT</version>
   </parent>
 
   <modules>
diff --git a/hyracks/pom.xml b/hyracks/pom.xml
index 4e8d3e3..a4a54f2 100644
--- a/hyracks/pom.xml
+++ b/hyracks/pom.xml
@@ -17,7 +17,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>edu.uci.ics.hyracks</groupId>
   <artifactId>hyracks</artifactId>
-  <version>0.2.9-SNAPSHOT</version>
+  <version>0.2.10-SNAPSHOT</version>
   <packaging>pom</packaging>
   <name>hyracks</name>
 
diff --git a/pom.xml b/pom.xml
index 45bf31f..a851758 100644
--- a/pom.xml
+++ b/pom.xml
@@ -17,7 +17,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>edu.uci.ics.hyracks</groupId>
   <artifactId>fullstack</artifactId>
-  <version>0.2.9-SNAPSHOT</version>
+  <version>0.2.10-SNAPSHOT</version>
   <packaging>pom</packaging>
   <name>hyracks-ecosystem-full-stack</name>
 
diff --git a/pregelix/pom.xml b/pregelix/pom.xml
index b8be121..de5ef3b 100644
--- a/pregelix/pom.xml
+++ b/pregelix/pom.xml
@@ -17,7 +17,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>edu.uci.ics.hyracks</groupId>
   <artifactId>pregelix</artifactId>
-  <version>0.2.9-SNAPSHOT</version>
+  <version>0.2.10-SNAPSHOT</version>
   <packaging>pom</packaging>
   <name>pregelix</name>
 
diff --git a/pregelix/pregelix-api/pom.xml b/pregelix/pregelix-api/pom.xml
index a92348a..0152a15 100644
--- a/pregelix/pregelix-api/pom.xml
+++ b/pregelix/pregelix-api/pom.xml
@@ -21,7 +21,7 @@
 	<parent>
 		<groupId>edu.uci.ics.hyracks</groupId>
 		<artifactId>pregelix</artifactId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 	</parent>
 
 	<properties>
@@ -82,7 +82,7 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-dataflow-common</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
@@ -95,7 +95,7 @@
 		<dependency>
                         <groupId>edu.uci.ics.hyracks</groupId>
                         <artifactId>hyracks-hdfs-core</artifactId>
-                        <version>0.2.9-SNAPSHOT</version>
+                        <version>0.2.10-SNAPSHOT</version>
                         <type>jar</type>
                         <scope>compile</scope>
                 </dependency>
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/graph/GlobalAggregator.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/graph/GlobalAggregator.java
index 08c7151..5ea6413 100644
--- a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/graph/GlobalAggregator.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/graph/GlobalAggregator.java
@@ -20,6 +20,7 @@
 import org.apache.hadoop.io.WritableComparable;
 
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 
 /**
  * This is the abstract class to implement for aggregating the state of all the vertices globally in the graph.
@@ -39,7 +40,7 @@
  */
 
 @SuppressWarnings("rawtypes")
-public abstract class GlobalAggregator<I extends WritableComparable, V extends Writable, E extends Writable, M extends Writable, P extends Writable, F extends Writable> {
+public abstract class GlobalAggregator<I extends WritableComparable, V extends Writable, E extends Writable, M extends WritableSizable, P extends Writable, F extends Writable> {
     /**
      * initialize aggregator
      */
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/graph/MessageCombiner.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/graph/MessageCombiner.java
index f5daf99..fa03c0c 100644
--- a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/graph/MessageCombiner.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/graph/MessageCombiner.java
@@ -19,6 +19,7 @@
 import org.apache.hadoop.io.WritableComparable;
 
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 
 /**
  * This is the abstract class to implement for combining of messages that are sent to the same vertex.
@@ -36,7 +37,7 @@
  *        the type of the partially combined messages
  */
 @SuppressWarnings("rawtypes")
-public abstract class MessageCombiner<I extends WritableComparable, M extends Writable, P extends Writable> {
+public abstract class MessageCombiner<I extends WritableComparable, M extends WritableSizable, P extends Writable> {
 
     /**
      * initialize combiner
@@ -82,4 +83,36 @@
      * @return the final message List
      */
     public abstract MsgList<M> finishFinal();
+
+    /**
+     * init the combiner for all segmented bags for one key
+     * 
+     * @return the final message List
+     */
+    public void initAll(MsgList providedMsgList) {
+        init(providedMsgList);
+    }
+
+    /**
+     * finish final combiner for all segmented bags for one key
+     * 
+     * @return the final message List
+     */
+    public MsgList<M> finishFinalAll() {
+        return finishFinal();
+    }
+
+    /**
+     * @return the accumulated byte size
+     */
+    public int estimateAccumulatedStateByteSizePartial(I vertexIndex, M msg) throws HyracksDataException {
+        return 0;
+    }
+
+    /**
+     * @return the accumulated byte size
+     */
+    public int estimateAccumulatedStateByteSizeFinal(I vertexIndex, P partialAggregate) throws HyracksDataException {
+        return 0;
+    }
 }
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/graph/MsgList.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/graph/MsgList.java
index 104f396..51b62e4 100644
--- a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/graph/MsgList.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/graph/MsgList.java
@@ -15,8 +15,11 @@
 
 package edu.uci.ics.pregelix.api.graph;
 
-import org.apache.hadoop.io.Writable;
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
 
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 import edu.uci.ics.pregelix.api.util.ArrayListWritable;
 import edu.uci.ics.pregelix.api.util.BspUtils;
 
@@ -27,9 +30,11 @@
  * @param <M>
  *            message type
  */
-public class MsgList<M extends Writable> extends ArrayListWritable<M> {
+public class MsgList<M extends WritableSizable> extends ArrayListWritable<M> {
     /** Defining a layout version for a serializable class. */
     private static final long serialVersionUID = 1L;
+    private byte start = 1;
+    private byte end = 2;
 
     /**
      * Default constructor.s
@@ -43,4 +48,34 @@
     public void setClass() {
         setClass((Class<M>) BspUtils.getMessageValueClass(getConf()));
     }
+
+    @Override
+    public void write(DataOutput output) throws IOException {
+        output.writeByte(start | end);
+        super.write(output);
+    }
+
+    @Override
+    public void readFields(DataInput input) throws IOException {
+        byte startEnd = input.readByte();
+        this.start = (byte) (startEnd & 1);
+        this.end = (byte) (startEnd & 2);
+        super.readFields(input);
+    }
+
+    public final void setSegmentStart(boolean segStart) {
+        this.start = (byte) (segStart ? 1 : 0);
+    }
+
+    public final void setSegmentEnd(boolean segEnd) {
+        this.end = (byte) (segEnd ? 2 : 0);
+    }
+
+    public boolean segmentStart() {
+        return start == 1 ? true : false;
+    }
+
+    public boolean segmentEnd() {
+        return end == 2 ? true : false;
+    }
 }
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 4175078..26cb8d0 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
@@ -24,15 +24,18 @@
 import java.util.List;
 import java.util.Map;
 
+import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.io.Writable;
 import org.apache.hadoop.io.WritableComparable;
+import org.apache.hadoop.io.WritableUtils;
 import org.apache.hadoop.mapreduce.TaskAttemptContext;
 
 import edu.uci.ics.hyracks.api.comm.IFrameWriter;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
 import edu.uci.ics.hyracks.dataflow.common.comm.io.FrameTupleAppender;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 import edu.uci.ics.pregelix.api.util.BspUtils;
-import edu.uci.ics.pregelix.api.util.SerDeUtils;
+import edu.uci.ics.pregelix.api.util.JobStateUtils;
 
 /**
  * User applications should all inherit {@link Vertex}, and implement their own
@@ -48,7 +51,7 @@
  *            Message value type
  */
 @SuppressWarnings("rawtypes")
-public abstract class Vertex<I extends WritableComparable, V extends Writable, E extends Writable, M extends Writable>
+public abstract class Vertex<I extends WritableComparable, V extends Writable, E extends Writable, M extends WritableSizable>
         implements Writable {
     private static long superstep = 0;
     /** Class-wide number of vertices */
@@ -75,6 +78,8 @@
     private boolean hasMessage = false;
     /** created new vertex */
     private boolean createdNewLiveVertex = false;
+    /** terminate the partition */
+    private boolean terminatePartition = false;
 
     /**
      * use object pool for re-using objects
@@ -87,12 +92,23 @@
     private int usedValue = 0;
 
     /**
-     * The key method that users need to implement
+     * The key method that users need to implement to process
+     * incoming messages in each superstep.
+     * 1. In a superstep, this method can be called multiple times in a continuous manner for a single
+     * vertex, each of which is to process a batch of messages. (Note that
+     * this only happens for the case when the mssages for a single vertex
+     * exceed one frame.)
+     * 2. In each superstep, before any invocation of this method for a vertex,
+     * open() is called; after all the invocations of this method for the vertex,
+     * close is called.
+     * 3. In each partition, the vertex Java object is reused
+     * for all the vertice to be processed in the same partition. (The model
+     * is the same as the key-value objects in hadoop map tasks.)
      * 
      * @param msgIterator
      *            an iterator of incoming messages
      */
-    public abstract void compute(Iterator<M> msgIterator);
+    public abstract void compute(Iterator<M> msgIterator) throws Exception;
 
     /**
      * Add an edge for the vertex.
@@ -254,7 +270,7 @@
             delegate.setVertex(this);
         }
         destEdgeList.clear();
-        long edgeMapSize = SerDeUtils.readVLong(in);
+        long edgeMapSize = WritableUtils.readVLong(in);
         for (long i = 0; i < edgeMapSize; ++i) {
             Edge<I, E> edge = allocateEdge();
             edge.setConf(getContext().getConfiguration());
@@ -262,7 +278,7 @@
             addEdge(edge);
         }
         msgList.clear();
-        long msgListSize = SerDeUtils.readVLong(in);
+        long msgListSize = WritableUtils.readVLong(in);
         for (long i = 0; i < msgListSize; ++i) {
             M msg = allocateMessage();
             msg.readFields(in);
@@ -281,11 +297,11 @@
         if (vertexValue != null) {
             vertexValue.write(out);
         }
-        SerDeUtils.writeVLong(out, destEdgeList.size());
+        WritableUtils.writeVLong(out, destEdgeList.size());
         for (Edge<I, E> edge : destEdgeList) {
             edge.write(out);
         }
-        SerDeUtils.writeVLong(out, msgList.size());
+        WritableUtils.writeVLong(out, msgList.size());
         for (M msg : msgList) {
             msg.write(out);
         }
@@ -569,4 +585,61 @@
         Vertex.context = context;
     }
 
+    @Override
+    public int hashCode() {
+        return vertexId.hashCode();
+    }
+
+    @Override
+    public boolean equals(Object object) {
+        Vertex vertex = (Vertex) object;
+        return vertexId.equals(vertex.getVertexId());
+    }
+
+    /**
+     * called immediately before invocations of compute() on a vertex
+     * Users can override this method to initiate the state for a vertex
+     * before the compute() invocations
+     */
+    public void open() {
+
+    }
+
+    /**
+     * called immediately after all the invocations of compute() on a vertex
+     * Users can override this method to initiate the state for a vertex
+     * before the compute() invocations
+     */
+    public void close() {
+
+    }
+
+    /**
+     * Terminate the current partition where the current vertex stays in.
+     * This will immediately take effect and the upcoming vertice in the
+     * same partition cannot be processed.
+     */
+    protected final void terminatePartition() {
+        voteToHalt();
+        terminatePartition = true;
+    }
+
+    /**
+     * Terminate the Pregelix job.
+     * This will take effect only when the current iteration completed.
+     * 
+     * @throws Exception
+     */
+    protected void terminateJob() throws Exception {
+        Configuration conf = getContext().getConfiguration();
+        JobStateUtils.writeForceTerminationState(conf, BspUtils.getJobId(conf));
+    }
+
+    /***
+     * @return true if the partition is terminated; false otherwise
+     */
+    public boolean isPartitionTerminated() {
+        return terminatePartition;
+    }
+
 }
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/Sizable.java
similarity index 64%
copy from hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
copy to pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/Sizable.java
index cde5022..568500b 100644
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/Sizable.java
@@ -12,17 +12,12 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+package edu.uci.ics.pregelix.api.io;
 
-package edu.uci.ics.hyracks.storage.am.btree.exceptions;
+/**
+ * @author yingyib
+ */
+public interface Sizable {
 
-public class BTreeDuplicateKeyException extends BTreeException {
-    private static final long serialVersionUID = 1L;
-
-    public BTreeDuplicateKeyException(Exception e) {
-        super(e);
-    }
-
-    public BTreeDuplicateKeyException(String message) {
-        super(message);
-    }
+    public int sizeInBytes();
 }
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/VertexInputFormat.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/VertexInputFormat.java
index c841b1a..73af190 100644
--- a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/VertexInputFormat.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/VertexInputFormat.java
@@ -40,7 +40,7 @@
  *            Message data
  */
 @SuppressWarnings("rawtypes")
-public abstract class VertexInputFormat<I extends WritableComparable, V extends Writable, E extends Writable, M extends Writable> {
+public abstract class VertexInputFormat<I extends WritableComparable, V extends Writable, E extends Writable, M extends WritableSizable> {
     /**
      * Logically split the vertices for a graph processing application.
      * Each {@link InputSplit} is then assigned to a worker for processing.
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/VertexReader.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/VertexReader.java
index e6c62ba..ba8b561 100644
--- a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/VertexReader.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/VertexReader.java
@@ -39,7 +39,7 @@
  *            Message data
  */
 @SuppressWarnings("rawtypes")
-public interface VertexReader<I extends WritableComparable, V extends Writable, E extends Writable, M extends Writable> {
+public interface VertexReader<I extends WritableComparable, V extends Writable, E extends Writable, M extends WritableSizable> {
     /**
      * Use the input split and context t o setup reading the vertices.
      * Guaranteed to be called prior to any other function.
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/WritableSizable.java
similarity index 64%
copy from hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
copy to pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/WritableSizable.java
index cde5022..ee13f76 100644
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/WritableSizable.java
@@ -12,17 +12,13 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+package edu.uci.ics.pregelix.api.io;
 
-package edu.uci.ics.hyracks.storage.am.btree.exceptions;
+import org.apache.hadoop.io.Writable;
 
-public class BTreeDuplicateKeyException extends BTreeException {
-    private static final long serialVersionUID = 1L;
+/**
+ * @author yingyib
+ */
+public interface WritableSizable extends Writable, Sizable {
 
-    public BTreeDuplicateKeyException(Exception e) {
-        super(e);
-    }
-
-    public BTreeDuplicateKeyException(String message) {
-        super(message);
-    }
 }
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/generated/GeneratedVertexInputFormat.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/generated/GeneratedVertexInputFormat.java
index 985bcff..1d3c427 100644
--- a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/generated/GeneratedVertexInputFormat.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/generated/GeneratedVertexInputFormat.java
@@ -26,13 +26,14 @@
 
 import edu.uci.ics.pregelix.api.io.BasicGenInputSplit;
 import edu.uci.ics.pregelix.api.io.VertexInputFormat;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 
 /**
  * This VertexInputFormat is meant for testing/debugging. It simply generates
  * some vertex data that can be consumed by test applications.
  */
 @SuppressWarnings("rawtypes")
-public abstract class GeneratedVertexInputFormat<I extends WritableComparable, V extends Writable, E extends Writable, M extends Writable>
+public abstract class GeneratedVertexInputFormat<I extends WritableComparable, V extends Writable, E extends Writable, M extends WritableSizable>
         extends VertexInputFormat<I, V, E, M> {
 
     @Override
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/generated/GeneratedVertexReader.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/generated/GeneratedVertexReader.java
index 92c8728..376d45d 100644
--- a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/generated/GeneratedVertexReader.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/generated/GeneratedVertexReader.java
@@ -25,6 +25,7 @@
 
 import edu.uci.ics.pregelix.api.io.BasicGenInputSplit;
 import edu.uci.ics.pregelix.api.io.VertexReader;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 
 /**
  * Used by GeneratedVertexInputFormat to read some generated data
@@ -37,7 +38,7 @@
  *            Edge value
  */
 @SuppressWarnings("rawtypes")
-public abstract class GeneratedVertexReader<I extends WritableComparable, V extends Writable, E extends Writable, M extends Writable>
+public abstract class GeneratedVertexReader<I extends WritableComparable, V extends Writable, E extends Writable, M extends WritableSizable>
         implements VertexReader<I, V, E, M> {
     /** Records read so far */
     protected long recordsRead = 0;
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/internal/InternalVertexInputFormat.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/internal/InternalVertexInputFormat.java
new file mode 100644
index 0000000..503b521
--- /dev/null
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/internal/InternalVertexInputFormat.java
@@ -0,0 +1,80 @@
+/*
+ * 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.api.io.internal;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.apache.hadoop.io.Writable;
+import org.apache.hadoop.io.WritableComparable;
+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.SequenceFileInputFormat;
+
+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.io.WritableSizable;
+
+/**
+ * @author yingyib
+ */
+@SuppressWarnings("rawtypes")
+public class InternalVertexInputFormat<I extends WritableComparable, V extends Writable, E extends Writable, M extends WritableSizable>
+        extends VertexInputFormat<I, V, E, M> {
+    /** Uses the SequenceFileInputFormat to do everything */
+    protected SequenceFileInputFormat sequenceInputFormat = new SequenceFileInputFormat();
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public List<InputSplit> getSplits(JobContext context, int numWorkers) throws IOException, InterruptedException {
+        return sequenceInputFormat.getSplits(context);
+    }
+
+    @Override
+    public VertexReader<I, V, E, M> createVertexReader(InputSplit split, TaskAttemptContext context) throws IOException {
+        return new VertexReader<I, V, E, M>() {
+
+            @Override
+            public void initialize(InputSplit inputSplit, TaskAttemptContext context) throws IOException,
+                    InterruptedException {
+
+            }
+
+            @Override
+            public boolean nextVertex() throws IOException, InterruptedException {
+                return false;
+            }
+
+            @Override
+            public Vertex<I, V, E, M> getCurrentVertex() throws IOException, InterruptedException {
+                return null;
+            }
+
+            @Override
+            public void close() throws IOException {
+
+            }
+
+            @Override
+            public float getProgress() throws IOException, InterruptedException {
+                return 0;
+            }
+
+        };
+    }
+
+}
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/internal/InternalVertexOutputFormat.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/internal/InternalVertexOutputFormat.java
new file mode 100644
index 0000000..0581658
--- /dev/null
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/internal/InternalVertexOutputFormat.java
@@ -0,0 +1,104 @@
+/*
+ * 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.api.io.internal;
+
+import java.io.IOException;
+
+import org.apache.hadoop.io.Writable;
+import org.apache.hadoop.io.WritableComparable;
+import org.apache.hadoop.mapreduce.JobContext;
+import org.apache.hadoop.mapreduce.OutputCommitter;
+import org.apache.hadoop.mapreduce.TaskAttemptContext;
+
+import edu.uci.ics.pregelix.api.graph.Vertex;
+import edu.uci.ics.pregelix.api.io.VertexOutputFormat;
+import edu.uci.ics.pregelix.api.io.VertexWriter;
+
+/**
+ * @author yingyib
+ */
+@SuppressWarnings("rawtypes")
+public class InternalVertexOutputFormat<I extends WritableComparable, V extends Writable, E extends Writable> extends
+        VertexOutputFormat<I, V, E> {
+
+    @Override
+    public VertexWriter<I, V, E> createVertexWriter(TaskAttemptContext context) throws IOException,
+            InterruptedException {
+        return new VertexWriter<I, V, E>() {
+
+            @Override
+            public void initialize(TaskAttemptContext context) throws IOException, InterruptedException {
+
+            }
+
+            @Override
+            public void writeVertex(Vertex<I, V, E, ?> vertex) throws IOException, InterruptedException {
+
+            }
+
+            @Override
+            public void close(TaskAttemptContext context) throws IOException, InterruptedException {
+
+            }
+
+        };
+    }
+
+    @Override
+    public void checkOutputSpecs(JobContext context) throws IOException, InterruptedException {
+
+    }
+
+    @Override
+    public OutputCommitter getOutputCommitter(TaskAttemptContext context) throws IOException, InterruptedException {
+        return new OutputCommitter() {
+
+            @Override
+            public void abortTask(TaskAttemptContext arg0) throws IOException {
+                // TODO Auto-generated method stub
+                
+            }
+
+            @Override
+            public void cleanupJob(JobContext arg0) throws IOException {
+                // TODO Auto-generated method stub
+                
+            }
+
+            @Override
+            public void commitTask(TaskAttemptContext arg0) throws IOException {
+                // TODO Auto-generated method stub
+                
+            }
+
+            @Override
+            public boolean needsTaskCommit(TaskAttemptContext arg0) throws IOException {
+                return false;
+            }
+
+            @Override
+            public void setupJob(JobContext arg0) throws IOException {
+                
+            }
+
+            @Override
+            public void setupTask(TaskAttemptContext arg0) throws IOException {
+                
+            }
+
+        };
+    }
+
+}
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/text/TextVertexInputFormat.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/text/TextVertexInputFormat.java
index 2254ae4..0faf516 100644
--- a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/text/TextVertexInputFormat.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/text/TextVertexInputFormat.java
@@ -30,6 +30,7 @@
 
 import edu.uci.ics.pregelix.api.io.VertexInputFormat;
 import edu.uci.ics.pregelix.api.io.VertexReader;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 
 /**
  * Abstract class that users should subclass to use their own text based vertex
@@ -45,7 +46,7 @@
  *            Message value
  */
 @SuppressWarnings("rawtypes")
-public abstract class TextVertexInputFormat<I extends WritableComparable, V extends Writable, E extends Writable, M extends Writable>
+public abstract class TextVertexInputFormat<I extends WritableComparable, V extends Writable, E extends Writable, M extends WritableSizable>
         extends VertexInputFormat<I, V, E, M> {
     /** Uses the TextInputFormat to do everything */
     protected TextInputFormat textInputFormat = new TextInputFormat();
@@ -62,7 +63,7 @@
      * @param <E>
      *            Edge value
      */
-    public static abstract class TextVertexReader<I extends WritableComparable, V extends Writable, E extends Writable, M extends Writable>
+    public static abstract class TextVertexReader<I extends WritableComparable, V extends Writable, E extends Writable, M extends WritableSizable>
             implements VertexReader<I, V, E, M> {
         /** Internal line record reader */
         private final RecordReader<LongWritable, Text> lineRecordReader;
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 dae7818..d2d5cf0 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
@@ -201,4 +201,9 @@
     final public void setLSMStorage(boolean variableSizedUpdateHeavyFlag) {
         getConfiguration().setBoolean(UPDATE_INTENSIVE, variableSizedUpdateHeavyFlag);
     }
+
+    @Override
+    public String toString() {
+        return getJobName();
+    }
 }
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/ArrayListWritable.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/ArrayListWritable.java
index 7a9e5d5..1683541 100644
--- a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/ArrayListWritable.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/ArrayListWritable.java
@@ -141,9 +141,6 @@
         used = 0;
         this.clear();
         int numValues = in.readInt(); // read number of values
-        if (numValues > 100) {
-            System.out.println("num values: " + numValues);
-        }
         for (int i = 0; i < numValues; i++) {
             M value = allocateValue();
             value.readFields(in); // read a value
@@ -153,9 +150,6 @@
 
     public void write(DataOutput out) throws IOException {
         int numValues = size();
-        if (numValues > 100) {
-            System.out.println("write num values: " + numValues);
-        }
         out.writeInt(numValues); // write number of values
         for (int i = 0; i < numValues; i++) {
             get(i).write(out);
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 03c37dc..ff4ee91 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
@@ -28,6 +28,7 @@
 import edu.uci.ics.pregelix.api.graph.VertexPartitioner;
 import edu.uci.ics.pregelix.api.io.VertexInputFormat;
 import edu.uci.ics.pregelix.api.io.VertexOutputFormat;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 import edu.uci.ics.pregelix.api.job.PregelixJob;
 
 /**
@@ -49,7 +50,7 @@
      * @return User's vertex input format class
      */
     @SuppressWarnings({ "rawtypes", "unchecked" })
-    public static <I extends WritableComparable, V extends Writable, E extends Writable, M extends Writable> Class<? extends VertexInputFormat<I, V, E, M>> getVertexInputFormatClass(
+    public static <I extends WritableComparable, V extends Writable, E extends Writable, M extends WritableSizable> Class<? extends VertexInputFormat<I, V, E, M>> getVertexInputFormatClass(
             Configuration conf) {
         return (Class<? extends VertexInputFormat<I, V, E, M>>) conf.getClass(PregelixJob.VERTEX_INPUT_FORMAT_CLASS,
                 null, VertexInputFormat.class);
@@ -63,7 +64,7 @@
      * @return Instantiated user vertex input format class
      */
     @SuppressWarnings("rawtypes")
-    public static <I extends WritableComparable, V extends Writable, E extends Writable, M extends Writable> VertexInputFormat<I, V, E, M> createVertexInputFormat(
+    public static <I extends WritableComparable, V extends Writable, E extends Writable, M extends WritableSizable> VertexInputFormat<I, V, E, M> createVertexInputFormat(
             Configuration conf) {
         Class<? extends VertexInputFormat<I, V, E, M>> vertexInputFormatClass = getVertexInputFormatClass(conf);
         VertexInputFormat<I, V, E, M> inputFormat = ReflectionUtils.newInstance(vertexInputFormatClass, conf);
@@ -106,7 +107,7 @@
      * @return User's vertex combiner class
      */
     @SuppressWarnings({ "rawtypes", "unchecked" })
-    public static <I extends WritableComparable, M extends Writable, P extends Writable> Class<? extends MessageCombiner<I, M, P>> getMessageCombinerClass(
+    public static <I extends WritableComparable, M extends WritableSizable, P extends Writable> Class<? extends MessageCombiner<I, M, P>> getMessageCombinerClass(
             Configuration conf) {
         return (Class<? extends MessageCombiner<I, M, P>>) conf.getClass(PregelixJob.Message_COMBINER_CLASS,
                 DefaultMessageCombiner.class, MessageCombiner.class);
@@ -120,7 +121,7 @@
      * @return User's vertex combiner class
      */
     @SuppressWarnings({ "rawtypes", "unchecked" })
-    public static <I extends WritableComparable, V extends Writable, E extends Writable, M extends Writable, P extends Writable, F extends Writable> Class<? extends GlobalAggregator<I, V, E, M, P, F>> getGlobalAggregatorClass(
+    public static <I extends WritableComparable, V extends Writable, E extends Writable, M extends WritableSizable, P extends Writable, F extends Writable> Class<? extends GlobalAggregator<I, V, E, M, P, F>> getGlobalAggregatorClass(
             Configuration conf) {
         return (Class<? extends GlobalAggregator<I, V, E, M, P, F>>) conf.getClass(PregelixJob.GLOBAL_AGGREGATOR_CLASS,
                 GlobalCountAggregator.class, GlobalAggregator.class);
@@ -138,7 +139,7 @@
      * @return Instantiated user vertex combiner class
      */
     @SuppressWarnings("rawtypes")
-    public static <I extends WritableComparable, M extends Writable, P extends Writable> MessageCombiner<I, M, P> createMessageCombiner(
+    public static <I extends WritableComparable, M extends WritableSizable, P extends Writable> MessageCombiner<I, M, P> createMessageCombiner(
             Configuration conf) {
         Class<? extends MessageCombiner<I, M, P>> vertexCombinerClass = getMessageCombinerClass(conf);
         return ReflectionUtils.newInstance(vertexCombinerClass, conf);
@@ -164,7 +165,7 @@
      * @return Instantiated user vertex combiner class
      */
     @SuppressWarnings("rawtypes")
-    public static <I extends WritableComparable, V extends Writable, E extends Writable, M extends Writable, P extends Writable, F extends Writable> GlobalAggregator<I, V, E, M, P, F> createGlobalAggregator(
+    public static <I extends WritableComparable, V extends Writable, E extends Writable, M extends WritableSizable, P extends Writable, F extends Writable> GlobalAggregator<I, V, E, M, P, F> createGlobalAggregator(
             Configuration conf) {
         Class<? extends GlobalAggregator<I, V, E, M, P, F>> globalAggregatorClass = getGlobalAggregatorClass(conf);
         return ReflectionUtils.newInstance(globalAggregatorClass, conf);
@@ -178,7 +179,7 @@
      * @return User's vertex class
      */
     @SuppressWarnings({ "rawtypes", "unchecked" })
-    public static <I extends WritableComparable, V extends Writable, E extends Writable, M extends Writable> Class<? extends Vertex<I, V, E, M>> getVertexClass(
+    public static <I extends WritableComparable, V extends Writable, E extends Writable, M extends WritableSizable> Class<? extends Vertex<I, V, E, M>> getVertexClass(
             Configuration conf) {
         return (Class<? extends Vertex<I, V, E, M>>) conf.getClass(PregelixJob.VERTEX_CLASS, null, Vertex.class);
     }
@@ -191,7 +192,7 @@
      * @return Instantiated user vertex
      */
     @SuppressWarnings("rawtypes")
-    public static <I extends WritableComparable, V extends Writable, E extends Writable, M extends Writable> Vertex<I, V, E, M> createVertex(
+    public static <I extends WritableComparable, V extends Writable, E extends Writable, M extends WritableSizable> Vertex<I, V, E, M> createVertex(
             Configuration conf) {
         Class<? extends Vertex<I, V, E, M>> vertexClass = getVertexClass(conf);
         Vertex<I, V, E, M> vertex = ReflectionUtils.newInstance(vertexClass, conf);
@@ -299,7 +300,7 @@
      * @return User's vertex message value class
      */
     @SuppressWarnings("unchecked")
-    public static <M extends Writable> Class<M> getMessageValueClass(Configuration conf) {
+    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);
@@ -369,7 +370,7 @@
      *            Configuration to check
      * @return Instantiated user vertex message value
      */
-    public static <M extends Writable> M createMessageValue(Configuration conf) {
+    public static <M extends WritableSizable> M createMessageValue(Configuration conf) {
         Class<M> messageValueClass = getMessageValueClass(conf);
         try {
             return messageValueClass.newInstance();
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/DefaultMessageCombiner.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/DefaultMessageCombiner.java
index d2d90a2..feb9e2f 100644
--- a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/DefaultMessageCombiner.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/DefaultMessageCombiner.java
@@ -14,42 +14,82 @@
  */
 package edu.uci.ics.pregelix.api.util;
 
-import org.apache.hadoop.io.Writable;
 import org.apache.hadoop.io.WritableComparable;
 
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.pregelix.api.graph.MessageCombiner;
 import edu.uci.ics.pregelix.api.graph.MsgList;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 
 @SuppressWarnings({ "rawtypes", "unchecked" })
-public class DefaultMessageCombiner<I extends WritableComparable, M extends Writable> extends
+public class DefaultMessageCombiner<I extends WritableComparable, M extends WritableSizable> extends
         MessageCombiner<I, M, MsgList> {
     private MsgList<M> msgList;
+    private int metaSlot = 8;
+    private int accumulatedSize = metaSlot;
 
     @Override
     public void init(MsgList providedMsgList) {
+        realInit(providedMsgList);
+        this.msgList.setSegmentStart(false);
+    }
+
+    private void realInit(MsgList providedMsgList) {
         this.msgList = providedMsgList;
         this.msgList.clearElements();
+        this.accumulatedSize = metaSlot;
     }
 
     @Override
     public void stepPartial(I vertexIndex, M msg) throws HyracksDataException {
         msgList.addElement(msg);
+        accumulatedSize += msg.sizeInBytes();
     }
 
     @Override
     public void stepFinal(I vertexIndex, MsgList partialAggregate) throws HyracksDataException {
         msgList.addAllElements(partialAggregate);
+        for (int i = 0; i < partialAggregate.size(); i++) {
+            accumulatedSize += ((M) partialAggregate.get(i)).sizeInBytes();
+        }
     }
 
     @Override
     public MsgList finishPartial() {
+        msgList.setSegmentEnd(false);
         return msgList;
     }
 
     @Override
     public MsgList<M> finishFinal() {
+        msgList.setSegmentEnd(false);
         return msgList;
     }
 
+    @Override
+    public void initAll(MsgList providedMsgList) {
+        realInit(providedMsgList);
+        msgList.setSegmentStart(true);
+    }
+
+    @Override
+    public MsgList<M> finishFinalAll() {
+        msgList.setSegmentEnd(true);
+        return msgList;
+    }
+
+    @Override
+    public int estimateAccumulatedStateByteSizePartial(I vertexIndex, M msg) throws HyracksDataException {
+        return accumulatedSize + msg.sizeInBytes();
+    }
+
+    @Override
+    public int estimateAccumulatedStateByteSizeFinal(I vertexIndex, MsgList partialAggregate)
+            throws HyracksDataException {
+        int size = accumulatedSize;
+        for (int i = 0; i < partialAggregate.size(); i++) {
+            size += ((M) partialAggregate.get(i)).sizeInBytes();
+        }
+        return size;
+    }
 }
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/GlobalCountAggregator.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/GlobalCountAggregator.java
index ffc6526..9a95f09 100644
--- a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/GlobalCountAggregator.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/GlobalCountAggregator.java
@@ -21,9 +21,10 @@
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.pregelix.api.graph.GlobalAggregator;
 import edu.uci.ics.pregelix.api.graph.Vertex;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 
 @SuppressWarnings("rawtypes")
-public class GlobalCountAggregator<I extends WritableComparable, V extends Writable, E extends Writable, M extends Writable>
+public class GlobalCountAggregator<I extends WritableComparable, V extends Writable, E extends Writable, M extends WritableSizable>
         extends GlobalAggregator<I, V, E, M, LongWritable, LongWritable> {
 
     private LongWritable state = new LongWritable(0);
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/JobStateUtils.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/JobStateUtils.java
new file mode 100644
index 0000000..4a98167
--- /dev/null
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/JobStateUtils.java
@@ -0,0 +1,64 @@
+/*
+ * 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.api.util;
+
+import java.io.IOException;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FSDataOutputStream;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+
+import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+
+/**
+ * @author yingyib
+ */
+public class JobStateUtils {
+
+    public static final String TMP_DIR = "/tmp/";
+
+    public static void writeForceTerminationState(Configuration conf, String jobId) throws HyracksDataException {
+        try {
+            FileSystem dfs = FileSystem.get(conf);
+            String pathStr = TMP_DIR + jobId + "fterm";
+            Path path = new Path(pathStr);
+            if (!dfs.exists(path)) {
+                FSDataOutputStream output = dfs.create(path, true);
+                output.writeBoolean(true);
+                output.flush();
+                output.close();
+            }
+        } catch (IOException e) {
+            throw new HyracksDataException(e);
+        }
+    }
+
+    public static boolean readForceTerminationState(Configuration conf, String jobId) throws HyracksDataException {
+        try {
+            FileSystem dfs = FileSystem.get(conf);
+            String pathStr = TMP_DIR + jobId + "fterm";
+            Path path = new Path(pathStr);
+            if (dfs.exists(path)) {
+                return true;
+            } else {
+                return false;
+            }
+        } catch (IOException e) {
+            throw new HyracksDataException(e);
+        }
+    }
+
+}
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/ResetableByteArrayInputStream.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/ResetableByteArrayInputStream.java
index 7d5f627..f9cad9f 100755
--- a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/ResetableByteArrayInputStream.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/ResetableByteArrayInputStream.java
@@ -36,19 +36,12 @@
     public int read() {
         int remaining = data.length - position;
         int value = remaining > 0 ? (data[position++] & 0xff) : -1;
-        if (LOGGER.isLoggable(Level.FINEST)) {
-            LOGGER.finest("read(): value: " + value + " remaining: " + remaining + " position: " + position);
-        }
         return value;
     }
 
     @Override
     public int read(byte[] bytes, int offset, int length) {
         int remaining = data.length - position;
-        if (LOGGER.isLoggable(Level.FINEST)) {
-            LOGGER.finest("read(bytes[], int, int): remaining: " + remaining + " offset: " + offset + " length: "
-                    + length + " position: " + position);
-        }
         if (remaining == 0) {
             return -1;
         }
@@ -57,4 +50,9 @@
         position += l;
         return l;
     }
-}
\ No newline at end of file
+
+    @Override
+    public int available() {
+        return data.length - position;
+    }
+}
diff --git a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/SerDeUtils.java b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/SerDeUtils.java
index 25b07ff..a4336a3 100644
--- a/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/SerDeUtils.java
+++ b/pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/util/SerDeUtils.java
@@ -40,47 +40,4 @@
         object.readFields(input);
     }
 
-    public static long readVLong(DataInput in) throws IOException {
-        int vLen = 0;
-        long value = 0L;
-        while (true) {
-            byte b = (byte) in.readByte();
-            ++vLen;
-            value += (((long) (b & 0x7f)) << ((vLen - 1) * 7));
-            if ((b & 0x80) == 0) {
-                break;
-            }
-        }
-        return value;
-    }
-
-    public static void writeVLong(DataOutput out, long value) throws IOException {
-        long data = value;
-        do {
-            byte b = (byte) (data & 0x7f);
-            data >>= 7;
-            if (data != 0) {
-                b |= 0x80;
-            }
-            out.write(b);
-        } while (data != 0);
-    }
-
-    public static long readVLong(byte[] data, int start, int length) {
-        int vLen = 0;
-        long value = 0L;
-        while (true) {
-            byte b = (byte) data[start];
-            ++vLen;
-            value += (((long) (b & 0x7f)) << ((vLen - 1) * 7));
-            if ((b & 0x80) == 0) {
-                break;
-            }
-            ++start;
-        }
-        if (vLen != length)
-            throw new IllegalStateException("length mismatch -- vLen:" + vLen + " length:" + length);
-        return value;
-    }
-
 }
diff --git a/pregelix/pregelix-core/pom.xml b/pregelix/pregelix-core/pom.xml
index c984ab8..a3f24f4 100644
--- a/pregelix/pregelix-core/pom.xml
+++ b/pregelix/pregelix-core/pom.xml
@@ -21,7 +21,7 @@
 	<parent>
 		<groupId>edu.uci.ics.hyracks</groupId>
 		<artifactId>pregelix</artifactId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 	</parent>
 
 
@@ -209,84 +209,84 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>pregelix-api</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>pregelix-dataflow-std</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>pregelix-dataflow</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-dataflow-std</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>pregelix-runtime</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<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>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-dataflow-common</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-data-std</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<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>0.2.9-SNAPSHOT</version>
+			<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>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-control-cc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-control-nc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
@@ -300,7 +300,7 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks.examples</groupId>
 			<artifactId>hyracks-integration-tests</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<scope>test</scope>
 		</dependency>
 		<dependency>
@@ -320,7 +320,7 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-ipc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
diff --git a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/base/IDriver.java b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/base/IDriver.java
index bc6c0cf..c72f392 100644
--- a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/base/IDriver.java
+++ b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/base/IDriver.java
@@ -15,6 +15,8 @@
 
 package edu.uci.ics.pregelix.core.base;
 
+import java.util.List;
+
 import edu.uci.ics.hyracks.api.exceptions.HyracksException;
 import edu.uci.ics.pregelix.api.job.PregelixJob;
 
@@ -29,6 +31,11 @@
 
     public void runJob(PregelixJob job, String ipAddress, int port) throws HyracksException;
 
+    public void runJobs(List<PregelixJob> jobs, String ipAddress, int port) throws HyracksException;
+
     public void runJob(PregelixJob job, Plan planChoice, String ipAddress, int port, boolean profiling)
             throws HyracksException;
+
+    public void runJobs(List<PregelixJob> jobs, Plan planChoice, String ipAddress, int port, boolean profiling)
+            throws HyracksException;
 }
diff --git a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/driver/Driver.java b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/driver/Driver.java
index 2d4064b..1b4f226 100644
--- a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/driver/Driver.java
+++ b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/driver/Driver.java
@@ -17,15 +17,19 @@
 
 import java.io.File;
 import java.io.FilenameFilter;
+import java.io.IOException;
 import java.net.URL;
 import java.net.URLClassLoader;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.EnumSet;
 import java.util.List;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
 import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
 
 import edu.uci.ics.hyracks.api.client.HyracksConnection;
@@ -36,6 +40,7 @@
 import edu.uci.ics.hyracks.api.job.JobId;
 import edu.uci.ics.hyracks.api.job.JobSpecification;
 import edu.uci.ics.pregelix.api.job.PregelixJob;
+import edu.uci.ics.pregelix.api.util.BspUtils;
 import edu.uci.ics.pregelix.core.base.IDriver;
 import edu.uci.ics.pregelix.core.jobgen.JobGen;
 import edu.uci.ics.pregelix.core.jobgen.JobGenInnerJoin;
@@ -48,11 +53,9 @@
 @SuppressWarnings("rawtypes")
 public class Driver implements IDriver {
     private static final Log LOG = LogFactory.getLog(Driver.class);
-    private JobGen jobGen;
-    private boolean profiling;
-
     private IHyracksClientConnection hcc;
     private Class exampleClass;
+    private boolean profiling = false;
 
     public Driver(Class exampleClass) {
         this.exampleClass = exampleClass;
@@ -64,93 +67,200 @@
     }
 
     @Override
+    public void runJobs(List<PregelixJob> jobs, String ipAddress, int port) throws HyracksException {
+        runJobs(jobs, Plan.OUTER_JOIN, ipAddress, port, false);
+    }
+
+    @Override
     public void runJob(PregelixJob job, Plan planChoice, String ipAddress, int port, boolean profiling)
             throws HyracksException {
+        runJobs(Collections.singletonList(job), planChoice, ipAddress, port, profiling);
+    }
+
+    @Override
+    public void runJobs(List<PregelixJob> jobs, Plan planChoice, String ipAddress, int port, boolean profiling)
+            throws HyracksException {
         try {
-            /** add hadoop configurations */
-            URL hadoopCore = job.getClass().getClassLoader().getResource("core-site.xml");
-            if (hadoopCore != null) {
-                job.getConfiguration().addResource(hadoopCore);
+            if (jobs.size() <= 0) {
+                throw new HyracksException("Please submit at least one job for execution!");
             }
-            URL hadoopMapRed = job.getClass().getClassLoader().getResource("mapred-site.xml");
-            if (hadoopMapRed != null) {
-                job.getConfiguration().addResource(hadoopMapRed);
-            }
-            URL hadoopHdfs = job.getClass().getClassLoader().getResource("hdfs-site.xml");
-            if (hadoopHdfs != null) {
-                job.getConfiguration().addResource(hadoopHdfs);
-            }
-            ClusterConfig.loadClusterConfig(ipAddress, port);
-
-            LOG.info("job started");
-            long start = System.currentTimeMillis();
-            long end = start;
-            long time = 0;
-
             this.profiling = profiling;
+            PregelixJob currentJob = jobs.get(0);
+            PregelixJob lastJob = currentJob;
+            JobGen jobGen = null;
 
-            switch (planChoice) {
-                case INNER_JOIN:
-                    jobGen = new JobGenInnerJoin(job);
-                    break;
-                case OUTER_JOIN:
-                    jobGen = new JobGenOuterJoin(job);
-                    break;
-                case OUTER_JOIN_SORT:
-                    jobGen = new JobGenOuterJoinSort(job);
-                    break;
-                case OUTER_JOIN_SINGLE_SORT:
-                    jobGen = new JobGenOuterJoinSingleSort(job);
-                    break;
-                default:
-                    jobGen = new JobGenInnerJoin(job);
-            }
+            /** prepare job -- deploy jars */
+            DeploymentId deploymentId = prepareJobs(ipAddress, port);
+            LOG.info("job started");
 
-            if (hcc == null)
-                hcc = new HyracksConnection(ipAddress, port);
+            int lastSnapshotJobIndex = 0;
+            int lastSnapshotSuperstep = 0;
+            boolean failed = false;
+            int retryCount = 0;
+            int maxRetryCount = 3;
 
-            URLClassLoader classLoader = (URLClassLoader) exampleClass.getClassLoader();
-            List<File> jars = new ArrayList<File>();
-            URL[] urls = classLoader.getURLs();
-            for (URL url : urls)
-                if (url.toString().endsWith(".jar"))
-                    jars.add(new File(url.getPath()));
-            DeploymentId deploymentId = installApplication(jars);
-
-            start = System.currentTimeMillis();
-            FileSystem dfs = FileSystem.get(job.getConfiguration());
-            dfs.delete(FileOutputFormat.getOutputPath(job), true);
-            runCreate(deploymentId, jobGen);
-            runDataLoad(deploymentId, jobGen);
-            end = System.currentTimeMillis();
-            time = end - start;
-            LOG.info("data loading finished " + time + "ms");
-            int i = 1;
-            boolean terminate = false;
             do {
-                start = System.currentTimeMillis();
-                runLoopBodyIteration(deploymentId, jobGen, i);
-                end = System.currentTimeMillis();
-                time = end - start;
-                LOG.info("iteration " + i + " finished " + time + "ms");
-                terminate = IterationUtils.readTerminationState(job.getConfiguration(), jobGen.getJobId())
-                        || IterationUtils.readForceTerminationState(job.getConfiguration(), jobGen.getJobId());
-                i++;
-            } while (!terminate);
+                try {
+                    for (int i = lastSnapshotJobIndex; i < jobs.size(); i++) {
+                        lastJob = currentJob;
+                        currentJob = jobs.get(i);
 
-            start = System.currentTimeMillis();
-            runHDFSWRite(deploymentId, jobGen);
-            runCleanup(deploymentId, jobGen);
-            end = System.currentTimeMillis();
-            time = end - start;
-            LOG.info("result writing finished " + time + "ms");
-            hcc.unDeployBinary(deploymentId);
+                        /** add hadoop configurations */
+                        addHadoopConfiguration(currentJob, ipAddress, port);
+
+                        /** load the data */
+                        if (i == 0 || compatible(lastJob, currentJob)) {
+                            if (i != 0) {
+                                finishJobs(jobGen, deploymentId);
+                            }
+                            jobGen = selectJobGen(planChoice, currentJob);
+                            loadData(currentJob, jobGen, deploymentId);
+                        } else {
+                            jobGen.reset(currentJob);
+                        }
+
+                        /** run loop-body jobs */
+                        runLoopBody(deploymentId, currentJob, jobGen, lastSnapshotSuperstep);
+                        runClearState(deploymentId, jobGen);
+                    }
+
+                    /** finish the jobs */
+                    finishJobs(jobGen, deploymentId);
+                    hcc.unDeployBinary(deploymentId);
+                } catch (IOException ioe) {
+                    /** disk failures */
+                    //restart from snapshot
+                    failed = true;
+                    retryCount++;
+                    ioe.printStackTrace();
+                }
+            } while (failed && retryCount < maxRetryCount);
             LOG.info("job finished");
         } catch (Exception e) {
             throw new HyracksException(e);
         }
     }
 
+    private boolean compatible(PregelixJob lastJob, PregelixJob currentJob) {
+        Class lastVertexIdClass = BspUtils.getVertexIndexClass(lastJob.getConfiguration());
+        Class lastVertexValueClass = BspUtils.getVertexValueClass(lastJob.getConfiguration());
+        Class lastEdgeValueClass = BspUtils.getEdgeValueClass(lastJob.getConfiguration());
+        Path lastOutputPath = FileOutputFormat.getOutputPath(lastJob);
+
+        Class currentVertexIdClass = BspUtils.getVertexIndexClass(currentJob.getConfiguration());
+        Class currentVertexValueClass = BspUtils.getVertexValueClass(currentJob.getConfiguration());
+        Class currentEdegeValueClass = BspUtils.getEdgeValueClass(currentJob.getConfiguration());
+        Path[] currentInputPaths = FileInputFormat.getInputPaths(currentJob);
+
+        return lastVertexIdClass.equals(currentVertexIdClass)
+                && lastVertexValueClass.equals(currentVertexValueClass)
+                && lastEdgeValueClass.equals(currentEdegeValueClass)
+                && (currentInputPaths.length == 0 || (currentInputPaths.length == 1 && lastOutputPath
+                        .equals(currentInputPaths[0])));
+    }
+
+    private JobGen selectJobGen(Plan planChoice, PregelixJob currentJob) {
+        JobGen jobGen;
+        switch (planChoice) {
+            case INNER_JOIN:
+                jobGen = new JobGenInnerJoin(currentJob);
+                break;
+            case OUTER_JOIN:
+                jobGen = new JobGenOuterJoin(currentJob);
+                break;
+            case OUTER_JOIN_SORT:
+                jobGen = new JobGenOuterJoinSort(currentJob);
+                break;
+            case OUTER_JOIN_SINGLE_SORT:
+                jobGen = new JobGenOuterJoinSingleSort(currentJob);
+                break;
+            default:
+                jobGen = new JobGenInnerJoin(currentJob);
+        }
+        return jobGen;
+    }
+
+    private long loadData(PregelixJob currentJob, JobGen jobGen, DeploymentId deploymentId) throws IOException,
+            Exception {
+        long start;
+        long end;
+        long time;
+        start = System.currentTimeMillis();
+        FileSystem dfs = FileSystem.get(currentJob.getConfiguration());
+        Path outputPath = FileOutputFormat.getOutputPath(currentJob);
+        if (outputPath != null) {
+            dfs.delete(outputPath, true);
+        }
+        runCreate(deploymentId, jobGen);
+        runDataLoad(deploymentId, jobGen);
+        end = System.currentTimeMillis();
+        time = end - start;
+        LOG.info("data loading finished " + time + "ms");
+        return time;
+    }
+
+    private void finishJobs(JobGen jobGen, DeploymentId deploymentId) throws Exception {
+        long start;
+        long end;
+        long time;
+        start = System.currentTimeMillis();
+        runHDFSWRite(deploymentId, jobGen);
+        runCleanup(deploymentId, jobGen);
+        end = System.currentTimeMillis();
+        time = end - start;
+        LOG.info("result writing finished " + time + "ms");
+    }
+
+    private DeploymentId prepareJobs(String ipAddress, int port) throws Exception {
+        if (hcc == null)
+            hcc = new HyracksConnection(ipAddress, port);
+
+        URLClassLoader classLoader = (URLClassLoader) exampleClass.getClassLoader();
+        List<File> jars = new ArrayList<File>();
+        URL[] urls = classLoader.getURLs();
+        for (URL url : urls)
+            if (url.toString().endsWith(".jar"))
+                jars.add(new File(url.getPath()));
+        DeploymentId deploymentId = installApplication(jars);
+        return deploymentId;
+    }
+
+    private void addHadoopConfiguration(PregelixJob job, String ipAddress, int port) throws HyracksException {
+        URL hadoopCore = job.getClass().getClassLoader().getResource("core-site.xml");
+        if (hadoopCore != null) {
+            job.getConfiguration().addResource(hadoopCore);
+        }
+        URL hadoopMapRed = job.getClass().getClassLoader().getResource("mapred-site.xml");
+        if (hadoopMapRed != null) {
+            job.getConfiguration().addResource(hadoopMapRed);
+        }
+        URL hadoopHdfs = job.getClass().getClassLoader().getResource("hdfs-site.xml");
+        if (hadoopHdfs != null) {
+            job.getConfiguration().addResource(hadoopHdfs);
+        }
+        ClusterConfig.loadClusterConfig(ipAddress, port);
+    }
+
+    private void runLoopBody(DeploymentId deploymentId, PregelixJob job, JobGen jobGen, int snapshotSuperstep)
+            throws Exception {
+        if (snapshotSuperstep > 0) {
+            /** reload the snapshot */
+        }
+        int i = snapshotSuperstep + 1;
+        boolean terminate = false;
+        long start, end, time;
+        do {
+            start = System.currentTimeMillis();
+            runLoopBodyIteration(deploymentId, jobGen, i);
+            end = System.currentTimeMillis();
+            time = end - start;
+            LOG.info(job + ": iteration " + i + " finished " + time + "ms");
+            terminate = IterationUtils.readTerminationState(job.getConfiguration(), jobGen.getJobId())
+                    || IterationUtils.readForceTerminationState(job.getConfiguration(), jobGen.getJobId());
+            i++;
+        } while (!terminate);
+    }
+
     private void runCreate(DeploymentId deploymentId, JobGen jobGen) throws Exception {
         try {
             JobSpecification treeCreateSpec = jobGen.generateCreatingJob();
@@ -196,6 +306,15 @@
         }
     }
 
+    private void runClearState(DeploymentId deploymentId, JobGen jobGen) throws Exception {
+        try {
+            JobSpecification clear = jobGen.generateClearState();
+            execute(deploymentId, clear);
+        } catch (Exception e) {
+            throw e;
+        }
+    }
+
     private void runJobArray(DeploymentId deploymentId, JobSpecification[] jobs) throws Exception {
         for (JobSpecification job : jobs) {
             execute(deploymentId, job);
@@ -204,6 +323,7 @@
 
     private void execute(DeploymentId deploymentId, JobSpecification job) throws Exception {
         job.setUseConnectorPolicyForScheduling(false);
+        job.setMaxReattempts(0);
         JobId jobId = hcc.startJob(deploymentId, job,
                 profiling ? EnumSet.of(JobFlag.PROFILE_RUNTIME) : EnumSet.noneOf(JobFlag.class));
         hcc.waitForCompletion(jobId);
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 478ac07..931ecc3 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
@@ -79,6 +79,7 @@
 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.HDFSFileWriteOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.VertexFileScanOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.VertexWriteOperatorDescriptor;
@@ -99,8 +100,8 @@
     protected static final float DEFAULT_BTREE_FILL_FACTOR = 1.00f;
     protected static final int tableSize = 10485767;
     protected static final String PRIMARY_INDEX = "primary";
-    protected final Configuration conf;
-    protected final PregelixJob giraphJob;
+    protected Configuration conf;
+    protected PregelixJob pregelixJob;
     protected IIndexLifecycleManagerProvider lcManagerProvider = IndexLifeCycleManagerProvider.INSTANCE;
     protected IStorageManagerInterface storageManagerInterface = StorageManagerInterface.INSTANCE;
     protected String jobId = new UUID(System.currentTimeMillis(), System.nanoTime()).toString();
@@ -111,9 +112,9 @@
     protected static final String SECONDARY_INDEX_EVEN = "secondary2";
 
     public JobGen(PregelixJob job) {
-        this.conf = job.getConfiguration();
-        this.giraphJob = job;
-        this.initJobConfiguration();
+        conf = job.getConfiguration();
+        pregelixJob = job;
+        initJobConfiguration();
         job.setJobId(jobId);
 
         // set the frame size to be the one user specified if the user did
@@ -128,6 +129,13 @@
         }
     }
 
+    public void reset(PregelixJob job) {
+        conf = job.getConfiguration();
+        pregelixJob = job;
+        initJobConfiguration();
+        job.setJobId(jobId);
+    }
+
     @SuppressWarnings({ "rawtypes", "unchecked" })
     private void initJobConfiguration() {
         Class vertexClass = conf.getClass(PregelixJob.VERTEX_CLASS, Vertex.class);
@@ -202,7 +210,7 @@
         VertexInputFormat inputFormat = BspUtils.createVertexInputFormat(conf);
         List<InputSplit> splits = new ArrayList<InputSplit>();
         try {
-            splits = inputFormat.getSplits(giraphJob, fileSplitProvider.getFileSplits().length);
+            splits = inputFormat.getSplits(pregelixJob, fileSplitProvider.getFileSplits().length);
             LOGGER.info("number of splits: " + splits.size());
             for (InputSplit split : splits)
                 LOGGER.info(split.toString());
@@ -241,7 +249,7 @@
         typeTraits[1] = new TypeTraits(false);
         TreeIndexBulkLoadOperatorDescriptor btreeBulkLoad = new TreeIndexBulkLoadOperatorDescriptor(spec,
                 storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits, comparatorFactories,
-                sortFields, fieldPermutation, DEFAULT_BTREE_FILL_FACTOR, false, 0, false,
+                sortFields, fieldPermutation, DEFAULT_BTREE_FILL_FACTOR, true, 0, false,
                 getIndexDataflowHelperFactory(), NoOpOperationCallbackFactory.INSTANCE);
         ClusterConfig.setLocationConstraint(spec, btreeBulkLoad);
 
@@ -280,7 +288,7 @@
         VertexInputFormat inputFormat = BspUtils.createVertexInputFormat(conf);
         List<InputSplit> splits = new ArrayList<InputSplit>();
         try {
-            splits = inputFormat.getSplits(giraphJob, fileSplitProvider.getFileSplits().length);
+            splits = inputFormat.getSplits(pregelixJob, fileSplitProvider.getFileSplits().length);
         } catch (Exception e) {
             throw new HyracksDataException(e);
         }
@@ -457,6 +465,17 @@
     }
 
     /***
+     * generate a "clear state" job
+     */
+    public JobSpecification generateClearState() throws HyracksException {
+        JobSpecification spec = new JobSpecification();
+        ClearStateOperatorDescriptor clearState = new ClearStateOperatorDescriptor(spec, jobId);
+        ClusterConfig.setLocationConstraint(spec, clearState);
+        spec.addRoot(clearState);
+        return spec;
+    }
+
+    /***
      * drop the sindex
      * 
      * @return JobSpecification
@@ -494,7 +513,7 @@
                     NoOpIOOperationCallback.INSTANCE, 0.01);
         } else {
             return new BTreeDataflowHelperFactory();
-       }
+        }
     }
 
     /** generate non-first iteration job */
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 db6c2c8..c144ddd 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
@@ -32,8 +32,6 @@
 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.group.IAggregatorDescriptorFactory;
-import edu.uci.ics.hyracks.dataflow.std.group.preclustered.PreclusteredGroupOperatorDescriptor;
 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;
@@ -54,6 +52,8 @@
 import edu.uci.ics.pregelix.dataflow.MaterializingWriteOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.TerminationStateWriterOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.base.IConfigurationFactory;
+import edu.uci.ics.pregelix.dataflow.group.ClusteredGroupOperatorDescriptor;
+import edu.uci.ics.pregelix.dataflow.group.IClusteredAggregatorDescriptorFactory;
 import edu.uci.ics.pregelix.dataflow.std.IndexNestedLoopJoinFunctionUpdateOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.std.IndexNestedLoopJoinOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.std.RuntimeHookOperatorDescriptor;
@@ -178,18 +178,18 @@
         /**
          * construct local pre-clustered group-by operator
          */
-        IAggregatorDescriptorFactory aggregatorFactory = DataflowUtils.getAccumulatingAggregatorFactory(conf, false,
-                false);
-        PreclusteredGroupOperatorDescriptor localGby = new PreclusteredGroupOperatorDescriptor(spec, keyFields,
+        IClusteredAggregatorDescriptorFactory aggregatorFactory = DataflowUtils.getAccumulatingAggregatorFactory(conf,
+                false, false);
+        ClusteredGroupOperatorDescriptor localGby = new ClusteredGroupOperatorDescriptor(spec, keyFields,
                 sortCmpFactories, aggregatorFactory, rdUnnestedMessage);
         ClusterConfig.setLocationConstraint(spec, localGby);
 
         /**
          * construct global group-by operator
          */
-        IAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(conf,
-                true, true);
-        PreclusteredGroupOperatorDescriptor globalGby = new PreclusteredGroupOperatorDescriptor(spec, keyFields,
+        IClusteredAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(
+                conf, true, true);
+        ClusteredGroupOperatorDescriptor globalGby = new ClusteredGroupOperatorDescriptor(spec, keyFields,
                 sortCmpFactories, aggregatorFactoryFinal, rdFinal);
         ClusterConfig.setLocationConstraint(spec, globalGby);
 
@@ -383,18 +383,18 @@
         /**
          * construct local pre-clustered group-by operator
          */
-        IAggregatorDescriptorFactory aggregatorFactory = DataflowUtils.getAccumulatingAggregatorFactory(conf, false,
-                false);
-        PreclusteredGroupOperatorDescriptor localGby = new PreclusteredGroupOperatorDescriptor(spec, keyFields,
+        IClusteredAggregatorDescriptorFactory aggregatorFactory = DataflowUtils.getAccumulatingAggregatorFactory(conf,
+                false, false);
+        ClusteredGroupOperatorDescriptor localGby = new ClusteredGroupOperatorDescriptor(spec, keyFields,
                 sortCmpFactories, aggregatorFactory, rdUnnestedMessage);
         ClusterConfig.setLocationConstraint(spec, localGby);
 
         /**
          * construct global group-by operator
          */
-        IAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(conf,
-                true, true);
-        PreclusteredGroupOperatorDescriptor globalGby = new PreclusteredGroupOperatorDescriptor(spec, keyFields,
+        IClusteredAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(
+                conf, true, true);
+        ClusteredGroupOperatorDescriptor globalGby = new ClusteredGroupOperatorDescriptor(spec, keyFields,
                 sortCmpFactories, aggregatorFactoryFinal, rdFinal);
         ClusterConfig.setLocationConstraint(spec, globalGby);
 
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 3af8921..c29ea18 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
@@ -32,8 +32,6 @@
 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.group.IAggregatorDescriptorFactory;
-import edu.uci.ics.hyracks.dataflow.std.group.preclustered.PreclusteredGroupOperatorDescriptor;
 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;
@@ -54,6 +52,8 @@
 import edu.uci.ics.pregelix.dataflow.MaterializingWriteOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.TerminationStateWriterOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.base.IConfigurationFactory;
+import edu.uci.ics.pregelix.dataflow.group.ClusteredGroupOperatorDescriptor;
+import edu.uci.ics.pregelix.dataflow.group.IClusteredAggregatorDescriptorFactory;
 import edu.uci.ics.pregelix.dataflow.std.IndexNestedLoopJoinFunctionUpdateOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.std.RuntimeHookOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.std.TreeSearchFunctionUpdateOperatorDescriptor;
@@ -144,9 +144,9 @@
         /**
          * construct local pre-clustered group-by operator
          */
-        IAggregatorDescriptorFactory aggregatorFactory = DataflowUtils.getAccumulatingAggregatorFactory(conf, false,
-                false);
-        PreclusteredGroupOperatorDescriptor localGby = new PreclusteredGroupOperatorDescriptor(spec, keyFields,
+        IClusteredAggregatorDescriptorFactory aggregatorFactory = DataflowUtils.getAccumulatingAggregatorFactory(conf,
+                false, false);
+        ClusteredGroupOperatorDescriptor localGby = new ClusteredGroupOperatorDescriptor(spec, keyFields,
                 sortCmpFactories, aggregatorFactory, rdUnnestedMessage);
         ClusterConfig.setLocationConstraint(spec, localGby);
 
@@ -155,9 +155,9 @@
          */
         RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
                 MsgList.class.getName());
-        IAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(conf,
-                true, true);
-        PreclusteredGroupOperatorDescriptor globalGby = new PreclusteredGroupOperatorDescriptor(spec, keyFields,
+        IClusteredAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(
+                conf, true, true);
+        ClusteredGroupOperatorDescriptor globalGby = new ClusteredGroupOperatorDescriptor(spec, keyFields,
                 sortCmpFactories, aggregatorFactoryFinal, rdFinal);
         ClusterConfig.setLocationConstraint(spec, globalGby);
 
@@ -198,8 +198,8 @@
         int[] fieldPermutation = new int[] { 0, 1 };
         TreeIndexInsertUpdateDeleteOperatorDescriptor insertOp = new TreeIndexInsertUpdateDeleteOperatorDescriptor(
                 spec, rdInsert, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits,
-                comparatorFactories, null, fieldPermutation, IndexOperation.INSERT, getIndexDataflowHelperFactory(), null,
-                NoOpOperationCallbackFactory.INSTANCE);
+                comparatorFactories, null, fieldPermutation, IndexOperation.INSERT, getIndexDataflowHelperFactory(),
+                null, NoOpOperationCallbackFactory.INSTANCE);
         ClusterConfig.setLocationConstraint(spec, insertOp);
 
         /**
@@ -208,8 +208,8 @@
         int[] fieldPermutationDelete = new int[] { 0 };
         TreeIndexInsertUpdateDeleteOperatorDescriptor deleteOp = new TreeIndexInsertUpdateDeleteOperatorDescriptor(
                 spec, rdDelete, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits,
-                comparatorFactories, null, fieldPermutationDelete, IndexOperation.DELETE, getIndexDataflowHelperFactory(),
-                null, NoOpOperationCallbackFactory.INSTANCE);
+                comparatorFactories, null, fieldPermutationDelete, IndexOperation.DELETE,
+                getIndexDataflowHelperFactory(), null, NoOpOperationCallbackFactory.INSTANCE);
         ClusterConfig.setLocationConstraint(spec, deleteOp);
 
         /** construct empty sink operator */
@@ -323,9 +323,10 @@
 
         IndexNestedLoopJoinFunctionUpdateOperatorDescriptor join = new IndexNestedLoopJoinFunctionUpdateOperatorDescriptor(
                 spec, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits, comparatorFactories,
-                JobGenUtil.getForwardScan(iteration), keyFields, keyFields, true, true, getIndexDataflowHelperFactory(), true,
-                nullWriterFactories, inputRdFactory, 5, new ComputeUpdateFunctionFactory(confFactory), preHookFactory,
-                null, rdUnnestedMessage, rdDummy, rdPartialAggregate, rdInsert, rdDelete);
+                JobGenUtil.getForwardScan(iteration), keyFields, keyFields, true, true,
+                getIndexDataflowHelperFactory(), true, nullWriterFactories, inputRdFactory, 5,
+                new ComputeUpdateFunctionFactory(confFactory), preHookFactory, null, rdUnnestedMessage, rdDummy,
+                rdPartialAggregate, rdInsert, rdDelete);
         ClusterConfig.setLocationConstraint(spec, join);
 
         /**
@@ -342,18 +343,18 @@
         /**
          * construct local pre-clustered group-by operator
          */
-        IAggregatorDescriptorFactory aggregatorFactory = DataflowUtils.getAccumulatingAggregatorFactory(conf, false,
-                false);
-        PreclusteredGroupOperatorDescriptor localGby = new PreclusteredGroupOperatorDescriptor(spec, keyFields,
+        IClusteredAggregatorDescriptorFactory aggregatorFactory = DataflowUtils.getAccumulatingAggregatorFactory(conf,
+                false, false);
+        ClusteredGroupOperatorDescriptor localGby = new ClusteredGroupOperatorDescriptor(spec, keyFields,
                 sortCmpFactories, aggregatorFactory, rdUnnestedMessage);
         ClusterConfig.setLocationConstraint(spec, localGby);
 
         /**
          * construct global group-by operator
          */
-        IAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(conf,
-                true, true);
-        PreclusteredGroupOperatorDescriptor globalGby = new PreclusteredGroupOperatorDescriptor(spec, keyFields,
+        IClusteredAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(
+                conf, true, true);
+        ClusteredGroupOperatorDescriptor globalGby = new ClusteredGroupOperatorDescriptor(spec, keyFields,
                 sortCmpFactories, aggregatorFactoryFinal, rdFinal);
         ClusterConfig.setLocationConstraint(spec, globalGby);
 
@@ -394,8 +395,8 @@
         int[] fieldPermutation = new int[] { 0, 1 };
         TreeIndexInsertUpdateDeleteOperatorDescriptor insertOp = new TreeIndexInsertUpdateDeleteOperatorDescriptor(
                 spec, rdInsert, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits,
-                comparatorFactories, null, fieldPermutation, IndexOperation.INSERT, getIndexDataflowHelperFactory(), null,
-                NoOpOperationCallbackFactory.INSTANCE);
+                comparatorFactories, null, fieldPermutation, IndexOperation.INSERT, getIndexDataflowHelperFactory(),
+                null, NoOpOperationCallbackFactory.INSTANCE);
         ClusterConfig.setLocationConstraint(spec, insertOp);
 
         /**
@@ -404,8 +405,8 @@
         int[] fieldPermutationDelete = new int[] { 0 };
         TreeIndexInsertUpdateDeleteOperatorDescriptor deleteOp = new TreeIndexInsertUpdateDeleteOperatorDescriptor(
                 spec, rdDelete, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits,
-                comparatorFactories, null, fieldPermutationDelete, IndexOperation.DELETE, getIndexDataflowHelperFactory(),
-                null, NoOpOperationCallbackFactory.INSTANCE);
+                comparatorFactories, null, fieldPermutationDelete, IndexOperation.DELETE,
+                getIndexDataflowHelperFactory(), null, NoOpOperationCallbackFactory.INSTANCE);
         ClusterConfig.setLocationConstraint(spec, deleteOp);
 
         /** construct empty sink operator */
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 50949aa..dc61971 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
@@ -31,8 +31,6 @@
 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.group.IAggregatorDescriptorFactory;
-import edu.uci.ics.hyracks.dataflow.std.group.preclustered.PreclusteredGroupOperatorDescriptor;
 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;
@@ -53,6 +51,8 @@
 import edu.uci.ics.pregelix.dataflow.MaterializingWriteOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.TerminationStateWriterOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.base.IConfigurationFactory;
+import edu.uci.ics.pregelix.dataflow.group.ClusteredGroupOperatorDescriptor;
+import edu.uci.ics.pregelix.dataflow.group.IClusteredAggregatorDescriptorFactory;
 import edu.uci.ics.pregelix.dataflow.std.IndexNestedLoopJoinFunctionUpdateOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.std.RuntimeHookOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.std.TreeSearchFunctionUpdateOperatorDescriptor;
@@ -148,9 +148,9 @@
          */
         RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
                 MsgList.class.getName());
-        IAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(conf,
-                true, false);
-        PreclusteredGroupOperatorDescriptor globalGby = new PreclusteredGroupOperatorDescriptor(spec, keyFields,
+        IClusteredAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(
+                conf, true, false);
+        ClusteredGroupOperatorDescriptor globalGby = new ClusteredGroupOperatorDescriptor(spec, keyFields,
                 sortCmpFactories, aggregatorFactoryFinal, rdFinal);
         ClusterConfig.setLocationConstraint(spec, globalGby);
 
@@ -190,8 +190,8 @@
         int[] fieldPermutation = new int[] { 0, 1 };
         TreeIndexInsertUpdateDeleteOperatorDescriptor insertOp = new TreeIndexInsertUpdateDeleteOperatorDescriptor(
                 spec, rdInsert, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits,
-                comparatorFactories, null, fieldPermutation, IndexOperation.INSERT, getIndexDataflowHelperFactory(), null,
-                NoOpOperationCallbackFactory.INSTANCE);
+                comparatorFactories, null, fieldPermutation, IndexOperation.INSERT, getIndexDataflowHelperFactory(),
+                null, NoOpOperationCallbackFactory.INSTANCE);
         ClusterConfig.setLocationConstraint(spec, insertOp);
 
         /**
@@ -200,8 +200,8 @@
         int[] fieldPermutationDelete = new int[] { 0 };
         TreeIndexInsertUpdateDeleteOperatorDescriptor deleteOp = new TreeIndexInsertUpdateDeleteOperatorDescriptor(
                 spec, rdDelete, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits,
-                comparatorFactories, null, fieldPermutationDelete, IndexOperation.DELETE, getIndexDataflowHelperFactory(),
-                null, NoOpOperationCallbackFactory.INSTANCE);
+                comparatorFactories, null, fieldPermutationDelete, IndexOperation.DELETE,
+                getIndexDataflowHelperFactory(), null, NoOpOperationCallbackFactory.INSTANCE);
         ClusterConfig.setLocationConstraint(spec, deleteOp);
 
         /** construct empty sink operator */
@@ -312,9 +312,10 @@
 
         IndexNestedLoopJoinFunctionUpdateOperatorDescriptor join = new IndexNestedLoopJoinFunctionUpdateOperatorDescriptor(
                 spec, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits, comparatorFactories,
-                JobGenUtil.getForwardScan(iteration), keyFields, keyFields, true, true, getIndexDataflowHelperFactory(), true,
-                nullWriterFactories, inputRdFactory, 5, new ComputeUpdateFunctionFactory(confFactory), preHookFactory,
-                null, rdUnnestedMessage, rdDummy, rdPartialAggregate, rdInsert, rdDelete);
+                JobGenUtil.getForwardScan(iteration), keyFields, keyFields, true, true,
+                getIndexDataflowHelperFactory(), true, nullWriterFactories, inputRdFactory, 5,
+                new ComputeUpdateFunctionFactory(confFactory), preHookFactory, null, rdUnnestedMessage, rdDummy,
+                rdPartialAggregate, rdInsert, rdDelete);
         ClusterConfig.setLocationConstraint(spec, join);
 
         /**
@@ -331,9 +332,9 @@
         /**
          * construct global group-by operator
          */
-        IAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(conf,
-                true, false);
-        PreclusteredGroupOperatorDescriptor globalGby = new PreclusteredGroupOperatorDescriptor(spec, keyFields,
+        IClusteredAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(
+                conf, true, false);
+        ClusteredGroupOperatorDescriptor globalGby = new ClusteredGroupOperatorDescriptor(spec, keyFields,
                 sortCmpFactories, aggregatorFactoryFinal, rdFinal);
         ClusterConfig.setLocationConstraint(spec, globalGby);
 
@@ -371,8 +372,8 @@
         int[] fieldPermutation = new int[] { 0, 1 };
         TreeIndexInsertUpdateDeleteOperatorDescriptor insertOp = new TreeIndexInsertUpdateDeleteOperatorDescriptor(
                 spec, rdInsert, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits,
-                comparatorFactories, null, fieldPermutation, IndexOperation.INSERT, getIndexDataflowHelperFactory(), null,
-                NoOpOperationCallbackFactory.INSTANCE);
+                comparatorFactories, null, fieldPermutation, IndexOperation.INSERT, getIndexDataflowHelperFactory(),
+                null, NoOpOperationCallbackFactory.INSTANCE);
         ClusterConfig.setLocationConstraint(spec, insertOp);
 
         /**
@@ -381,8 +382,8 @@
         int[] fieldPermutationDelete = new int[] { 0 };
         TreeIndexInsertUpdateDeleteOperatorDescriptor deleteOp = new TreeIndexInsertUpdateDeleteOperatorDescriptor(
                 spec, rdDelete, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits,
-                comparatorFactories, null, fieldPermutationDelete, IndexOperation.DELETE, getIndexDataflowHelperFactory(),
-                null, NoOpOperationCallbackFactory.INSTANCE);
+                comparatorFactories, null, fieldPermutationDelete, IndexOperation.DELETE,
+                getIndexDataflowHelperFactory(), null, NoOpOperationCallbackFactory.INSTANCE);
         ClusterConfig.setLocationConstraint(spec, deleteOp);
 
         /** construct empty sink operator */
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 362e413..34f723f 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
@@ -31,8 +31,6 @@
 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.group.IAggregatorDescriptorFactory;
-import edu.uci.ics.hyracks.dataflow.std.group.preclustered.PreclusteredGroupOperatorDescriptor;
 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;
@@ -53,6 +51,8 @@
 import edu.uci.ics.pregelix.dataflow.MaterializingWriteOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.TerminationStateWriterOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.base.IConfigurationFactory;
+import edu.uci.ics.pregelix.dataflow.group.ClusteredGroupOperatorDescriptor;
+import edu.uci.ics.pregelix.dataflow.group.IClusteredAggregatorDescriptorFactory;
 import edu.uci.ics.pregelix.dataflow.std.IndexNestedLoopJoinFunctionUpdateOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.std.RuntimeHookOperatorDescriptor;
 import edu.uci.ics.pregelix.dataflow.std.TreeSearchFunctionUpdateOperatorDescriptor;
@@ -143,9 +143,9 @@
         /**
          * construct local pre-clustered group-by operator
          */
-        IAggregatorDescriptorFactory aggregatorFactory = DataflowUtils.getAccumulatingAggregatorFactory(conf, false,
-                false);
-        PreclusteredGroupOperatorDescriptor localGby = new PreclusteredGroupOperatorDescriptor(spec, keyFields,
+        IClusteredAggregatorDescriptorFactory aggregatorFactory = DataflowUtils.getAccumulatingAggregatorFactory(conf,
+                false, false);
+        ClusteredGroupOperatorDescriptor localGby = new ClusteredGroupOperatorDescriptor(spec, keyFields,
                 sortCmpFactories, aggregatorFactory, rdUnnestedMessage);
         ClusterConfig.setLocationConstraint(spec, localGby);
 
@@ -161,9 +161,9 @@
          */
         RecordDescriptor rdFinal = DataflowUtils.getRecordDescriptorFromKeyValueClasses(vertexIdClass.getName(),
                 MsgList.class.getName());
-        IAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(conf,
-                true, true);
-        PreclusteredGroupOperatorDescriptor globalGby = new PreclusteredGroupOperatorDescriptor(spec, keyFields,
+        IClusteredAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(
+                conf, true, true);
+        ClusteredGroupOperatorDescriptor globalGby = new ClusteredGroupOperatorDescriptor(spec, keyFields,
                 sortCmpFactories, aggregatorFactoryFinal, rdFinal);
         ClusterConfig.setLocationConstraint(spec, globalGby);
 
@@ -204,8 +204,8 @@
         int[] fieldPermutation = new int[] { 0, 1 };
         TreeIndexInsertUpdateDeleteOperatorDescriptor insertOp = new TreeIndexInsertUpdateDeleteOperatorDescriptor(
                 spec, rdInsert, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits,
-                comparatorFactories, null, fieldPermutation, IndexOperation.INSERT, getIndexDataflowHelperFactory(), null,
-                NoOpOperationCallbackFactory.INSTANCE);
+                comparatorFactories, null, fieldPermutation, IndexOperation.INSERT, getIndexDataflowHelperFactory(),
+                null, NoOpOperationCallbackFactory.INSTANCE);
         ClusterConfig.setLocationConstraint(spec, insertOp);
 
         /**
@@ -214,8 +214,8 @@
         int[] fieldPermutationDelete = new int[] { 0 };
         TreeIndexInsertUpdateDeleteOperatorDescriptor deleteOp = new TreeIndexInsertUpdateDeleteOperatorDescriptor(
                 spec, rdDelete, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits,
-                comparatorFactories, null, fieldPermutationDelete, IndexOperation.DELETE, getIndexDataflowHelperFactory(),
-                null, NoOpOperationCallbackFactory.INSTANCE);
+                comparatorFactories, null, fieldPermutationDelete, IndexOperation.DELETE,
+                getIndexDataflowHelperFactory(), null, NoOpOperationCallbackFactory.INSTANCE);
         ClusterConfig.setLocationConstraint(spec, deleteOp);
 
         /** construct empty sink operator */
@@ -326,9 +326,10 @@
 
         IndexNestedLoopJoinFunctionUpdateOperatorDescriptor join = new IndexNestedLoopJoinFunctionUpdateOperatorDescriptor(
                 spec, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits, comparatorFactories,
-                JobGenUtil.getForwardScan(iteration), keyFields, keyFields, true, true, getIndexDataflowHelperFactory(), true,
-                nullWriterFactories, inputRdFactory, 5, new ComputeUpdateFunctionFactory(confFactory), preHookFactory,
-                null, rdUnnestedMessage, rdDummy, rdPartialAggregate, rdInsert, rdDelete);
+                JobGenUtil.getForwardScan(iteration), keyFields, keyFields, true, true,
+                getIndexDataflowHelperFactory(), true, nullWriterFactories, inputRdFactory, 5,
+                new ComputeUpdateFunctionFactory(confFactory), preHookFactory, null, rdUnnestedMessage, rdDummy,
+                rdPartialAggregate, rdInsert, rdDelete);
         ClusterConfig.setLocationConstraint(spec, join);
 
         /**
@@ -345,9 +346,9 @@
         /**
          * construct local pre-clustered group-by operator
          */
-        IAggregatorDescriptorFactory aggregatorFactory = DataflowUtils.getAccumulatingAggregatorFactory(conf, false,
-                false);
-        PreclusteredGroupOperatorDescriptor localGby = new PreclusteredGroupOperatorDescriptor(spec, keyFields,
+        IClusteredAggregatorDescriptorFactory aggregatorFactory = DataflowUtils.getAccumulatingAggregatorFactory(conf,
+                false, false);
+        ClusteredGroupOperatorDescriptor localGby = new ClusteredGroupOperatorDescriptor(spec, keyFields,
                 sortCmpFactories, aggregatorFactory, rdUnnestedMessage);
         ClusterConfig.setLocationConstraint(spec, localGby);
 
@@ -361,9 +362,9 @@
         /**
          * construct global group-by operator
          */
-        IAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(conf,
-                true, true);
-        PreclusteredGroupOperatorDescriptor globalGby = new PreclusteredGroupOperatorDescriptor(spec, keyFields,
+        IClusteredAggregatorDescriptorFactory aggregatorFactoryFinal = DataflowUtils.getAccumulatingAggregatorFactory(
+                conf, true, true);
+        ClusteredGroupOperatorDescriptor globalGby = new ClusteredGroupOperatorDescriptor(spec, keyFields,
                 sortCmpFactories, aggregatorFactoryFinal, rdFinal);
         ClusterConfig.setLocationConstraint(spec, globalGby);
 
@@ -404,8 +405,8 @@
         int[] fieldPermutation = new int[] { 0, 1 };
         TreeIndexInsertUpdateDeleteOperatorDescriptor insertOp = new TreeIndexInsertUpdateDeleteOperatorDescriptor(
                 spec, rdInsert, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits,
-                comparatorFactories, null, fieldPermutation, IndexOperation.INSERT, getIndexDataflowHelperFactory(), null,
-                NoOpOperationCallbackFactory.INSTANCE);
+                comparatorFactories, null, fieldPermutation, IndexOperation.INSERT, getIndexDataflowHelperFactory(),
+                null, NoOpOperationCallbackFactory.INSTANCE);
         ClusterConfig.setLocationConstraint(spec, insertOp);
 
         /**
@@ -414,8 +415,8 @@
         int[] fieldPermutationDelete = new int[] { 0 };
         TreeIndexInsertUpdateDeleteOperatorDescriptor deleteOp = new TreeIndexInsertUpdateDeleteOperatorDescriptor(
                 spec, rdDelete, storageManagerInterface, lcManagerProvider, fileSplitProvider, typeTraits,
-                comparatorFactories, null, fieldPermutationDelete, IndexOperation.DELETE, getIndexDataflowHelperFactory(),
-                null, NoOpOperationCallbackFactory.INSTANCE);
+                comparatorFactories, null, fieldPermutationDelete, IndexOperation.DELETE,
+                getIndexDataflowHelperFactory(), null, NoOpOperationCallbackFactory.INSTANCE);
         ClusterConfig.setLocationConstraint(spec, deleteOp);
 
         /** construct empty sink operator */
diff --git a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/clusterconfig/ClusterConfig.java b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/clusterconfig/ClusterConfig.java
index 49309ec..db18e53 100644
--- a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/clusterconfig/ClusterConfig.java
+++ b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/clusterconfig/ClusterConfig.java
@@ -26,6 +26,7 @@
 import java.util.Map;
 import java.util.Properties;
 import java.util.Random;
+import java.util.TreeMap;
 
 import org.apache.hadoop.mapreduce.InputSplit;
 
@@ -197,7 +198,8 @@
     public static void loadClusterConfig(String ipAddress, int port) throws HyracksException {
         try {
             IHyracksClientConnection hcc = new HyracksConnection(ipAddress, port);
-            Map<String, NodeControllerInfo> ncNameToNcInfos = hcc.getNodeControllerInfos();
+            Map<String, NodeControllerInfo> ncNameToNcInfos = new TreeMap<String, NodeControllerInfo>();
+            ncNameToNcInfos.putAll(hcc.getNodeControllerInfos());
             NCs = new String[ncNameToNcInfos.size()];
             ipToNcMapping = new HashMap<String, List<String>>();
             int i = 0;
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 0876893..3e01109 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
@@ -21,9 +21,9 @@
 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.HyracksException;
-import edu.uci.ics.hyracks.dataflow.std.group.IAggregatorDescriptorFactory;
 import edu.uci.ics.pregelix.core.hadoop.config.ConfigurationFactory;
 import edu.uci.ics.pregelix.core.runtime.touchpoint.WritableRecordDescriptorFactory;
+import edu.uci.ics.pregelix.dataflow.group.IClusteredAggregatorDescriptorFactory;
 import edu.uci.ics.pregelix.dataflow.std.base.IAggregateFunctionFactory;
 import edu.uci.ics.pregelix.dataflow.std.base.IRecordDescriptorFactory;
 import edu.uci.ics.pregelix.runtime.simpleagg.AccumulatingAggregatorFactory;
@@ -75,11 +75,11 @@
         return rdFactory;
     }
 
-    public static IAggregatorDescriptorFactory getAccumulatingAggregatorFactory(Configuration conf, boolean isFinal,
-            boolean partialAggAsInput) {
+    public static IClusteredAggregatorDescriptorFactory getAccumulatingAggregatorFactory(Configuration conf,
+            boolean isFinal, boolean partialAggAsInput) {
         IAggregateFunctionFactory aggFuncFactory = new AggregationFunctionFactory(new ConfigurationFactory(conf),
                 isFinal, partialAggAsInput);
-        IAggregatorDescriptorFactory aggregatorFactory = new AccumulatingAggregatorFactory(
+        IClusteredAggregatorDescriptorFactory aggregatorFactory = new AccumulatingAggregatorFactory(
                 new IAggregateFunctionFactory[] { aggFuncFactory });
         return aggregatorFactory;
     }
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 73b053f..e8a6b5c 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
@@ -14,8 +14,11 @@
  */
 package edu.uci.ics.pregelix.core.util;
 
+import java.io.File;
 import java.util.EnumSet;
 
+import org.apache.commons.io.FileUtils;
+
 import edu.uci.ics.hyracks.api.client.HyracksConnection;
 import edu.uci.ics.hyracks.api.client.IHyracksClientConnection;
 import edu.uci.ics.hyracks.api.job.JobFlag;
@@ -46,6 +49,10 @@
     private static IHyracksClientConnection hcc;
 
     public static void init() throws Exception {
+        FileUtils.forceMkdir(new File("dev1"));
+        FileUtils.forceMkdir(new File("dev2"));
+        FileUtils.forceMkdir(new File("dev3"));
+        FileUtils.forceMkdir(new File("dev4"));
         CCConfig ccConfig = new CCConfig();
         ccConfig.clientNetIpAddress = CC_HOST;
         ccConfig.clusterNetIpAddress = CC_HOST;
@@ -80,7 +87,7 @@
         ncConfig2.datasetIPAddress = "127.0.0.1";
         ncConfig2.nodeId = NC2_ID;
         ncConfig2.appNCMainClass = NCApplicationEntryPoint.class.getName();
-        ncConfig2.ioDevices="dev1,dev2";
+        ncConfig2.ioDevices="dev3,dev4";
         nc2 = new NodeControllerService(ncConfig2);
         nc2.start();
 
diff --git a/pregelix/pregelix-dataflow-std-base/pom.xml b/pregelix/pregelix-dataflow-std-base/pom.xml
index fade226..d4c0ee6 100644
--- a/pregelix/pregelix-dataflow-std-base/pom.xml
+++ b/pregelix/pregelix-dataflow-std-base/pom.xml
@@ -21,7 +21,7 @@
 	<parent>
     		<groupId>edu.uci.ics.hyracks</groupId>
     		<artifactId>pregelix</artifactId>
-    		<version>0.2.9-SNAPSHOT</version>
+    		<version>0.2.10-SNAPSHOT</version>
   	</parent>
 
 
@@ -87,15 +87,15 @@
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
-			<artifactId>pregelix-api</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<artifactId>hyracks-dataflow-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>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
diff --git a/pregelix/pregelix-dataflow-std-base/src/main/java/edu/uci/ics/pregelix/dataflow/std/base/IAggregateFunction.java b/pregelix/pregelix-dataflow-std-base/src/main/java/edu/uci/ics/pregelix/dataflow/std/base/IAggregateFunction.java
index 97db63f..c544b31 100644
--- a/pregelix/pregelix-dataflow-std-base/src/main/java/edu/uci/ics/pregelix/dataflow/std/base/IAggregateFunction.java
+++ b/pregelix/pregelix-dataflow-std-base/src/main/java/edu/uci/ics/pregelix/dataflow/std/base/IAggregateFunction.java
@@ -24,4 +24,10 @@
     public void step(IFrameTupleReference tuple) throws HyracksDataException;
 
     public void finish() throws HyracksDataException;
+
+    public void initAll() throws HyracksDataException;
+
+    public void finishAll() throws HyracksDataException;
+
+    public int estimateStep(IFrameTupleReference tuple) throws HyracksDataException;
 }
diff --git a/pregelix/pregelix-dataflow-std-base/src/main/java/edu/uci/ics/pregelix/dataflow/std/base/IAggregateFunctionFactory.java b/pregelix/pregelix-dataflow-std-base/src/main/java/edu/uci/ics/pregelix/dataflow/std/base/IAggregateFunctionFactory.java
index 58795d1..d5364da 100644
--- a/pregelix/pregelix-dataflow-std-base/src/main/java/edu/uci/ics/pregelix/dataflow/std/base/IAggregateFunctionFactory.java
+++ b/pregelix/pregelix-dataflow-std-base/src/main/java/edu/uci/ics/pregelix/dataflow/std/base/IAggregateFunctionFactory.java
@@ -16,11 +16,12 @@
 
 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.exceptions.HyracksException;
 import edu.uci.ics.hyracks.data.std.api.IDataOutputProvider;
 
 public interface IAggregateFunctionFactory extends Serializable {
-	public IAggregateFunction createAggregateFunction(IHyracksTaskContext ctx,
-			IDataOutputProvider provider) throws HyracksException;
+    public IAggregateFunction createAggregateFunction(IHyracksTaskContext ctx, IDataOutputProvider provider,
+            IFrameWriter writer) throws HyracksException;
 }
\ No newline at end of file
diff --git a/pregelix/pregelix-dataflow-std/pom.xml b/pregelix/pregelix-dataflow-std/pom.xml
index d628e91..9ec8e1d 100644
--- a/pregelix/pregelix-dataflow-std/pom.xml
+++ b/pregelix/pregelix-dataflow-std/pom.xml
@@ -21,7 +21,7 @@
 	<parent>
 		<groupId>edu.uci.ics.hyracks</groupId>
 		<artifactId>pregelix</artifactId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 	</parent>
 
 
@@ -88,84 +88,84 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>pregelix-dataflow-std-base</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-dataflow-std</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<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>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-dataflow-common</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-data-std</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-hdfs-core</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<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>0.2.9-SNAPSHOT</version>
+			<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>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-storage-am-lsm-btree</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-control-cc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-control-nc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-ipc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
diff --git a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/group/ClusteredGroupOperatorDescriptor.java b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/group/ClusteredGroupOperatorDescriptor.java
new file mode 100644
index 0000000..bb41953
--- /dev/null
+++ b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/group/ClusteredGroupOperatorDescriptor.java
@@ -0,0 +1,50 @@
+/*
+ * 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.group;
+
+import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
+import edu.uci.ics.hyracks.api.dataflow.IOperatorNodePushable;
+import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
+import edu.uci.ics.hyracks.api.dataflow.value.IRecordDescriptorProvider;
+import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
+import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+import edu.uci.ics.hyracks.api.job.IOperatorDescriptorRegistry;
+import edu.uci.ics.hyracks.dataflow.std.base.AbstractSingleActivityOperatorDescriptor;
+
+public class ClusteredGroupOperatorDescriptor extends AbstractSingleActivityOperatorDescriptor {
+    private final int[] groupFields;
+    private final IBinaryComparatorFactory[] comparatorFactories;
+    private final IClusteredAggregatorDescriptorFactory aggregatorFactory;
+
+    private static final long serialVersionUID = 1L;
+
+    public ClusteredGroupOperatorDescriptor(IOperatorDescriptorRegistry spec, int[] groupFields,
+            IBinaryComparatorFactory[] comparatorFactories, IClusteredAggregatorDescriptorFactory aggregatorFactory,
+            RecordDescriptor recordDescriptor) {
+        super(spec, 1, 1);
+        this.groupFields = groupFields;
+        this.comparatorFactories = comparatorFactories;
+        this.aggregatorFactory = aggregatorFactory;
+        recordDescriptors[0] = recordDescriptor;
+    }
+
+    @Override
+    public IOperatorNodePushable createPushRuntime(final IHyracksTaskContext ctx,
+            final IRecordDescriptorProvider recordDescProvider, int partition, int nPartitions)
+            throws HyracksDataException {
+        return new ClusteredGroupOperatorNodePushable(ctx, groupFields, comparatorFactories, aggregatorFactory,
+                recordDescProvider.getInputRecordDescriptor(getActivityId(), 0), recordDescriptors[0]);
+    }
+}
\ No newline at end of file
diff --git a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/group/ClusteredGroupOperatorNodePushable.java b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/group/ClusteredGroupOperatorNodePushable.java
new file mode 100644
index 0000000..a95a46e
--- /dev/null
+++ b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/group/ClusteredGroupOperatorNodePushable.java
@@ -0,0 +1,79 @@
+/*
+ * 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.group;
+
+import java.nio.ByteBuffer;
+
+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.RecordDescriptor;
+import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+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.std.base.AbstractUnaryInputUnaryOutputOperatorNodePushable;
+
+class ClusteredGroupOperatorNodePushable extends AbstractUnaryInputUnaryOutputOperatorNodePushable {
+    private final IHyracksTaskContext ctx;
+    private final int[] groupFields;
+    private final IBinaryComparatorFactory[] comparatorFactories;
+    private final IClusteredAggregatorDescriptorFactory aggregatorFactory;
+    private final RecordDescriptor inRecordDescriptor;
+    private final RecordDescriptor outRecordDescriptor;
+    private ClusteredGroupWriter pgw;
+
+    ClusteredGroupOperatorNodePushable(IHyracksTaskContext ctx, int[] groupFields,
+            IBinaryComparatorFactory[] comparatorFactories, IClusteredAggregatorDescriptorFactory aggregatorFactory,
+            RecordDescriptor inRecordDescriptor, RecordDescriptor outRecordDescriptor) {
+        this.ctx = ctx;
+        this.groupFields = groupFields;
+        this.comparatorFactories = comparatorFactories;
+        this.aggregatorFactory = aggregatorFactory;
+        this.inRecordDescriptor = inRecordDescriptor;
+        this.outRecordDescriptor = outRecordDescriptor;
+    }
+
+    @Override
+    public void open() throws HyracksDataException {
+        final IBinaryComparator[] comparators = new IBinaryComparator[comparatorFactories.length];
+        for (int i = 0; i < comparatorFactories.length; ++i) {
+            comparators[i] = comparatorFactories[i].createBinaryComparator();
+        }
+        final ByteBuffer copyFrame = ctx.allocateFrame();
+        final FrameTupleAccessor copyFrameAccessor = new FrameTupleAccessor(ctx.getFrameSize(), inRecordDescriptor);
+        copyFrameAccessor.reset(copyFrame);
+        ByteBuffer outFrame = ctx.allocateFrame();
+        final FrameTupleAppender appender = new FrameTupleAppender(ctx.getFrameSize());
+        appender.reset(outFrame, true);
+        pgw = new ClusteredGroupWriter(ctx, groupFields, comparators, aggregatorFactory, inRecordDescriptor,
+                outRecordDescriptor, writer);
+        pgw.open();
+    }
+
+    @Override
+    public void nextFrame(ByteBuffer buffer) throws HyracksDataException {
+        pgw.nextFrame(buffer);
+    }
+
+    @Override
+    public void fail() throws HyracksDataException {
+        pgw.fail();
+    }
+
+    @Override
+    public void close() throws HyracksDataException {
+        pgw.close();
+    }
+}
\ No newline at end of file
diff --git a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/group/ClusteredGroupWriter.java b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/group/ClusteredGroupWriter.java
new file mode 100644
index 0000000..4b4a1c3
--- /dev/null
+++ b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/group/ClusteredGroupWriter.java
@@ -0,0 +1,165 @@
+/*
+ * 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.group;
+
+import java.nio.ByteBuffer;
+
+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.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;
+
+public class ClusteredGroupWriter implements IFrameWriter {
+    private final int[] groupFields;
+    private final IBinaryComparator[] comparators;
+    private final IAggregatorDescriptor aggregator;
+    private final AggregateState aggregateState;
+    private final IFrameWriter writer;
+    private final ByteBuffer copyFrame;
+    private final FrameTupleAccessor inFrameAccessor;
+    private final FrameTupleAccessor copyFrameAccessor;
+
+    private final ByteBuffer outFrame;
+    private final FrameTupleAppender appender;
+    private final ArrayTupleBuilder tupleBuilder;
+
+    private boolean first;
+
+    public ClusteredGroupWriter(IHyracksTaskContext ctx, int[] groupFields, IBinaryComparator[] comparators,
+            IClusteredAggregatorDescriptorFactory aggregatorFactory, RecordDescriptor inRecordDesc,
+            RecordDescriptor outRecordDesc, IFrameWriter writer) throws HyracksDataException {
+        this.groupFields = groupFields;
+        this.comparators = comparators;
+        this.writer = writer;
+        copyFrame = ctx.allocateFrame();
+        inFrameAccessor = new FrameTupleAccessor(ctx.getFrameSize(), inRecordDesc);
+        copyFrameAccessor = new FrameTupleAccessor(ctx.getFrameSize(), inRecordDesc);
+        copyFrameAccessor.reset(copyFrame);
+
+        outFrame = ctx.allocateFrame();
+        appender = new FrameTupleAppender(ctx.getFrameSize());
+        appender.reset(outFrame, true);
+
+        tupleBuilder = new ArrayTupleBuilder(outRecordDesc.getFields().length);
+        this.aggregator = aggregatorFactory.createAggregator(ctx, inRecordDesc, outRecordDesc, groupFields, groupFields, writer, outFrame, appender);
+        this.aggregateState = aggregator.createAggregateStates();
+    }
+
+    @Override
+    public void open() throws HyracksDataException {
+        writer.open();
+        first = true;
+    }
+
+    @Override
+    public void nextFrame(ByteBuffer buffer) throws HyracksDataException {
+        inFrameAccessor.reset(buffer);
+        int nTuples = inFrameAccessor.getTupleCount();
+        for (int i = 0; i < nTuples; ++i) {
+            if (first) {
+
+                tupleBuilder.reset();
+                for (int j = 0; j < groupFields.length; j++) {
+                    tupleBuilder.addField(inFrameAccessor, i, groupFields[j]);
+                }
+                aggregator.init(tupleBuilder, inFrameAccessor, i, aggregateState);
+
+                first = false;
+
+            } else {
+                if (i == 0) {
+                    switchGroupIfRequired(copyFrameAccessor, copyFrameAccessor.getTupleCount() - 1, inFrameAccessor, i);
+                } else {
+                    switchGroupIfRequired(inFrameAccessor, i - 1, inFrameAccessor, i);
+                }
+
+            }
+        }
+        FrameUtils.copy(buffer, copyFrame);
+    }
+
+    private void switchGroupIfRequired(FrameTupleAccessor prevTupleAccessor, int prevTupleIndex,
+            FrameTupleAccessor currTupleAccessor, int currTupleIndex) throws HyracksDataException {
+        if (!sameGroup(prevTupleAccessor, prevTupleIndex, currTupleAccessor, currTupleIndex)) {
+            writeOutput(prevTupleAccessor, prevTupleIndex);
+
+            tupleBuilder.reset();
+            for (int j = 0; j < groupFields.length; j++) {
+                tupleBuilder.addField(currTupleAccessor, currTupleIndex, groupFields[j]);
+            }
+            aggregator.init(tupleBuilder, currTupleAccessor, currTupleIndex, aggregateState);
+        } else {
+            aggregator.aggregate(currTupleAccessor, currTupleIndex, null, 0, aggregateState);
+        }
+    }
+
+    private void writeOutput(final FrameTupleAccessor lastTupleAccessor, int lastTupleIndex)
+            throws HyracksDataException {
+        tupleBuilder.reset();
+        for (int j = 0; j < groupFields.length; j++) {
+            tupleBuilder.addField(lastTupleAccessor, lastTupleIndex, groupFields[j]);
+        }
+        aggregator.outputFinalResult(tupleBuilder, lastTupleAccessor, lastTupleIndex, aggregateState);
+        if (!appender.appendSkipEmptyField(tupleBuilder.getFieldEndOffsets(), tupleBuilder.getByteArray(), 0,
+                tupleBuilder.getSize())) {
+            FrameUtils.flushFrame(outFrame, writer);
+            appender.reset(outFrame, true);
+            if (!appender.appendSkipEmptyField(tupleBuilder.getFieldEndOffsets(), tupleBuilder.getByteArray(), 0,
+                    tupleBuilder.getSize())) {
+                throw new HyracksDataException("The output of size " + tupleBuilder.getSize()
+                        + " cannot be fit into a frame of size " + outFrame.array().length);
+            }
+        }
+
+    }
+
+    private boolean sameGroup(FrameTupleAccessor a1, int t1Idx, FrameTupleAccessor a2, int t2Idx) {
+        for (int i = 0; i < comparators.length; ++i) {
+            int fIdx = groupFields[i];
+            int s1 = a1.getTupleStartOffset(t1Idx) + a1.getFieldSlotsLength() + a1.getFieldStartOffset(t1Idx, fIdx);
+            int l1 = a1.getFieldLength(t1Idx, fIdx);
+            int s2 = a2.getTupleStartOffset(t2Idx) + a2.getFieldSlotsLength() + a2.getFieldStartOffset(t2Idx, fIdx);
+            int l2 = a2.getFieldLength(t2Idx, fIdx);
+            if (comparators[i].compare(a1.getBuffer().array(), s1, l1, a2.getBuffer().array(), s2, l2) != 0) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    @Override
+    public void fail() throws HyracksDataException {
+        writer.fail();
+    }
+
+    @Override
+    public void close() throws HyracksDataException {
+        if (!first) {
+            writeOutput(copyFrameAccessor, copyFrameAccessor.getTupleCount() - 1);
+            if (appender.getTupleCount() > 0) {
+                FrameUtils.flushFrame(outFrame, writer);
+            }
+        }
+        aggregateState.close();
+        writer.close();
+    }
+}
\ No newline at end of file
diff --git a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/group/IClusteredAggregatorDescriptorFactory.java b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/group/IClusteredAggregatorDescriptorFactory.java
new file mode 100644
index 0000000..3256f08
--- /dev/null
+++ b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/group/IClusteredAggregatorDescriptorFactory.java
@@ -0,0 +1,36 @@
+/*
+ * 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.group;
+
+import java.io.Serializable;
+import java.nio.ByteBuffer;
+
+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.FrameTupleAppender;
+import edu.uci.ics.hyracks.dataflow.std.group.IAggregatorDescriptor;
+
+/**
+ *
+ */
+public interface IClusteredAggregatorDescriptorFactory extends Serializable {
+
+    IAggregatorDescriptor createAggregator(IHyracksTaskContext ctx, RecordDescriptor inRecordDescriptor,
+            RecordDescriptor outRecordDescriptor, int[] keyFields, final int[] keyFieldsInPartialResults,
+            IFrameWriter resultWriter, ByteBuffer outputFrame, FrameTupleAppender appender) 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 5156dbf..7221cb5 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
@@ -157,16 +157,34 @@
             ITupleReference tupleRef = cursor.getTuple();
 
             /**
+             * merge with updated tuple
+             */
+            ITupleReference indexEntryTuple = tupleRef;
+            ITupleReference cachedUpdatedLastTuple = updateBuffer.getLastTuple();
+            if (cachedUpdatedLastTuple != null) {
+                if (compare(cachedUpdatedLastTuple, tupleRef) == 0) {
+                    indexEntryTuple = cachedUpdatedLastTuple;
+                }
+            }
+
+            /**
              * call the update function
              */
-            functionProxy.functionCall(leftAccessor, tIndex, tupleRef, cloneUpdateTb);
+            functionProxy.functionCall(leftAccessor, tIndex, indexEntryTuple, cloneUpdateTb);
 
-            //doing copy update
-            CopyUpdateUtil.copyUpdate(tempTupleReference, tupleRef, updateBuffer, cloneUpdateTb, indexAccessor, cursor,
-                    rangePred);
+            /**
+             * doing copy update
+             */
+            CopyUpdateUtil.copyUpdate(tempTupleReference, indexEntryTuple, updateBuffer, cloneUpdateTb, indexAccessor,
+                    cursor, rangePred);
         }
     }
 
+    /** compare tuples */
+    private int compare(ITupleReference left, ITupleReference right) throws Exception {
+        return lowKeySearchCmp.compare(left, right);
+    }
+
     @Override
     public void nextFrame(ByteBuffer buffer) throws HyracksDataException {
         accessor.reset(buffer);
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 4ca7533..b21cd2a 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
@@ -195,8 +195,10 @@
                 // TODO: currently use low key only, check what they mean
                 int cmp = compare(lowKey, currentTopTuple);
                 if (cmp <= 0) {
-                    if (cmp == 0)
+                    if (cmp == 0) {
                         outputMatch(i);
+                        currentTopTuple = cursor.getTuple();
+                    }
                     i++;
                 } else {
                     moveTreeCursor();
@@ -262,16 +264,28 @@
     }
 
     //for the join match casesos
-    private void writeResults(IFrameTupleAccessor leftAccessor, int tIndex, ITupleReference frameTuple)
+    private void writeResults(IFrameTupleAccessor leftAccessor, int tIndex, ITupleReference indexTuple)
             throws Exception {
         /**
+         * merge with the cached tuple, if any
+         */
+        ITupleReference indexEntryTuple = indexTuple;
+        ITupleReference cachedUpdatedLastTuple = updateBuffer.getLastTuple();
+        if (cachedUpdatedLastTuple != null) {
+            if (compare(cachedUpdatedLastTuple, indexTuple) == 0) {
+                indexEntryTuple = cachedUpdatedLastTuple;
+            }
+        }
+        /**
          * function call
          */
-        functionProxy.functionCall(leftAccessor, tIndex, frameTuple, cloneUpdateTb);
+        functionProxy.functionCall(leftAccessor, tIndex, indexEntryTuple, cloneUpdateTb);
 
-        //doing clone update
-        CopyUpdateUtil.copyUpdate(tempTupleReference, frameTuple, updateBuffer, cloneUpdateTb, indexAccessor, cursor,
-                rangePred);
+        /**
+         * doing clone update
+         */
+        CopyUpdateUtil.copyUpdate(tempTupleReference, indexEntryTuple, updateBuffer, cloneUpdateTb, indexAccessor,
+                cursor, rangePred);
     }
 
     /** write result for outer case */
@@ -290,4 +304,4 @@
     public void setOutputFrameWriter(int index, IFrameWriter writer, RecordDescriptor recordDesc) {
         writers[index] = writer;
     }
-}
\ No newline at end of file
+}
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 8709301..392f728 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
@@ -34,7 +34,7 @@
             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 possible, save the "real update" overhead
+                //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();
diff --git a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/ResetableByteArrayInputStream.java b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/ResetableByteArrayInputStream.java
index b697466..5be9ffc 100644
--- a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/ResetableByteArrayInputStream.java
+++ b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/ResetableByteArrayInputStream.java
@@ -15,11 +15,8 @@
 package edu.uci.ics.pregelix.dataflow.util;
 
 import java.io.InputStream;
-import java.util.logging.Level;
-import java.util.logging.Logger;
 
 public class ResetableByteArrayInputStream extends InputStream {
-    private static final Logger LOGGER = Logger.getLogger(ResetableByteArrayInputStream.class.getName());
 
     private byte[] data;
     private int position;
@@ -36,19 +33,12 @@
     public int read() {
         int remaining = data.length - position;
         int value = remaining > 0 ? (data[position++] & 0xff) : -1;
-        if (LOGGER.isLoggable(Level.FINEST)) {
-            LOGGER.finest("read(): value: " + value + " remaining: " + remaining + " position: " + position);
-        }
         return value;
     }
 
     @Override
     public int read(byte[] bytes, int offset, int length) {
         int remaining = data.length - position;
-        if (LOGGER.isLoggable(Level.FINEST)) {
-            LOGGER.finest("read(bytes[], int, int): remaining: " + remaining + " offset: " + offset + " length: "
-                    + length + " position: " + position);
-        }
         if (remaining == 0) {
             return -1;
         }
@@ -57,4 +47,9 @@
         position += l;
         return l;
     }
+
+    @Override
+    public int available() {
+        return data.length - position;
+    }
 }
\ No newline at end of file
diff --git a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/TupleDeserializer.java b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/TupleDeserializer.java
index 150bd8b..2fa1a4b 100644
--- a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/TupleDeserializer.java
+++ b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/TupleDeserializer.java
@@ -17,19 +17,15 @@
 
 import java.io.DataInputStream;
 import java.io.IOException;
-import java.util.logging.Level;
-import java.util.logging.Logger;
 
 import edu.uci.ics.hyracks.api.comm.IFrameTupleAccessor;
 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.FrameConstants;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
 
 public class TupleDeserializer {
-    private static final Logger LOGGER = Logger.getLogger(TupleDeserializer.class.getName());
-
+    private static String ERROR_MSG = "Out-of-bound read in your Writable implementations of types for vertex id, vertex value, edge value or message --- check your readFields and write implmenetation";
     private Object[] record;
     private RecordDescriptor recordDescriptor;
     private ResetableByteArrayInputStream bbis;
@@ -43,132 +39,120 @@
     }
 
     public Object[] deserializeRecord(ITupleReference tupleRef) throws HyracksDataException {
-        for (int i = 0; i < tupleRef.getFieldCount(); ++i) {
-            byte[] data = tupleRef.getFieldData(i);
-            int offset = tupleRef.getFieldStart(i);
-            bbis.setByteArray(data, offset);
+        try {
+            for (int i = 0; i < tupleRef.getFieldCount(); ++i) {
+                byte[] data = tupleRef.getFieldData(i);
+                int offset = tupleRef.getFieldStart(i);
+                int len = tupleRef.getFieldLength(i);
+                bbis.setByteArray(data, offset);
 
-            Object instance = recordDescriptor.getFields()[i].deserialize(di);
-            if (LOGGER.isLoggable(Level.FINEST)) {
-                LOGGER.finest(i + " " + instance);
-            }
-            record[i] = instance;
-            if (FrameConstants.DEBUG_FRAME_IO) {
-                try {
-                    if (di.readInt() != FrameConstants.FRAME_FIELD_MAGIC) {
-                        throw new HyracksDataException("Field magic mismatch");
-                    }
-                } catch (IOException e) {
-                    e.printStackTrace();
+                int availableBefore = bbis.available();
+                Object instance = recordDescriptor.getFields()[i].deserialize(di);
+                int availableAfter = bbis.available();
+                if (availableBefore - availableAfter > len) {
+                    throw new IllegalStateException(ERROR_MSG);
                 }
+
+                record[i] = instance;
             }
+            return record;
+        } catch (IOException e) {
+            throw new HyracksDataException(e);
         }
-        return record;
     }
 
     public Object[] deserializeRecord(IFrameTupleAccessor left, int tIndex, ITupleReference right)
             throws HyracksDataException {
-        byte[] data = left.getBuffer().array();
-        int tStart = left.getTupleStartOffset(tIndex) + left.getFieldSlotsLength();
-        int leftFieldCount = left.getFieldCount();
-        int fStart = tStart;
-        for (int i = 0; i < leftFieldCount; ++i) {
-            /**
-             * reset the input
-             */
-            fStart = tStart + left.getFieldStartOffset(tIndex, i);
-            bbis.setByteArray(data, fStart);
+        try {
+            /** skip vertex id field in deserialization */
+            byte[] data = left.getBuffer().array();
+            int tStart = left.getTupleStartOffset(tIndex) + left.getFieldSlotsLength();
+            int leftFieldCount = left.getFieldCount();
+            int fStart = tStart;
+            for (int i = 1; i < leftFieldCount; ++i) {
+                /**
+                 * reset the input
+                 */
+                fStart = tStart + left.getFieldStartOffset(tIndex, i);
+                int fieldLength = left.getFieldLength(tIndex, i);
+                bbis.setByteArray(data, fStart);
 
-            /**
-             * do deserialization
-             */
-            Object instance = recordDescriptor.getFields()[i].deserialize(di);
-            if (LOGGER.isLoggable(Level.FINEST)) {
-                LOGGER.finest(i + " " + instance);
-            }
-            record[i] = instance;
-            if (FrameConstants.DEBUG_FRAME_IO) {
-                try {
-                    if (di.readInt() != FrameConstants.FRAME_FIELD_MAGIC) {
-                        throw new HyracksDataException("Field magic mismatch");
-                    }
-                } catch (IOException e) {
-                    e.printStackTrace();
-                }
-            }
-        }
-        for (int i = leftFieldCount; i < record.length; ++i) {
-            byte[] rightData = right.getFieldData(i - leftFieldCount);
-            int rightOffset = right.getFieldStart(i - leftFieldCount);
-            bbis.setByteArray(rightData, rightOffset);
+                /**
+                 * do deserialization
+                 */
+                int availableBefore = bbis.available();
+                Object instance = recordDescriptor.getFields()[i].deserialize(di);
+                int availableAfter = bbis.available();
+                if (availableBefore - availableAfter > fieldLength) {
+                    throw new IllegalStateException(ERROR_MSG);
 
-            Object instance = recordDescriptor.getFields()[i].deserialize(di);
-            if (LOGGER.isLoggable(Level.FINEST)) {
-                LOGGER.finest(i + " " + instance);
-            }
-            record[i] = instance;
-            if (FrameConstants.DEBUG_FRAME_IO) {
-                try {
-                    if (di.readInt() != FrameConstants.FRAME_FIELD_MAGIC) {
-                        throw new HyracksDataException("Field magic mismatch");
-                    }
-                } catch (IOException e) {
-                    e.printStackTrace();
                 }
+                record[i] = instance;
             }
+            /** skip vertex id field in deserialization */
+            for (int i = leftFieldCount + 1; i < record.length; ++i) {
+                byte[] rightData = right.getFieldData(i - leftFieldCount);
+                int rightOffset = right.getFieldStart(i - leftFieldCount);
+                int len = right.getFieldLength(i - leftFieldCount);
+                bbis.setByteArray(rightData, rightOffset);
+
+                int availableBefore = bbis.available();
+                Object instance = recordDescriptor.getFields()[i].deserialize(di);
+                int availableAfter = bbis.available();
+                if (availableBefore - availableAfter > len) {
+                    throw new IllegalStateException(ERROR_MSG);
+                }
+                record[i] = instance;
+            }
+            return record;
+        } catch (IOException e) {
+            throw new HyracksDataException(e);
         }
-        return record;
     }
 
     public Object[] deserializeRecord(ArrayTupleBuilder tb, ITupleReference right) throws HyracksDataException {
-        byte[] data = tb.getByteArray();
-        int[] offset = tb.getFieldEndOffsets();
-        int start = 0;
-        for (int i = 0; i < offset.length; ++i) {
-            /**
-             * reset the input
-             */
-            bbis.setByteArray(data, start);
-            start = offset[i];
+        try {
+            byte[] data = tb.getByteArray();
+            int[] offset = tb.getFieldEndOffsets();
+            int start = 0;
+            /** skip vertex id fields in deserialization */
+            for (int i = 1; i < offset.length; ++i) {
+                /**
+                 * reset the input
+                 */
+                start = offset[i - 1];
+                bbis.setByteArray(data, start);
+                int fieldLength = i == 0 ? offset[0] : offset[i] - offset[i - 1];
 
-            /**
-             * do deserialization
-             */
-            Object instance = recordDescriptor.getFields()[i].deserialize(di);
-            if (LOGGER.isLoggable(Level.FINEST)) {
-                LOGGER.finest(i + " " + instance);
-            }
-            record[i] = instance;
-            if (FrameConstants.DEBUG_FRAME_IO) {
-                try {
-                    if (di.readInt() != FrameConstants.FRAME_FIELD_MAGIC) {
-                        throw new HyracksDataException("Field magic mismatch");
-                    }
-                } catch (IOException e) {
-                    e.printStackTrace();
+                /**
+                 * do deserialization
+                 */
+                int availableBefore = bbis.available();
+                Object instance = recordDescriptor.getFields()[i].deserialize(di);
+                int availableAfter = bbis.available();
+                if (availableBefore - availableAfter > fieldLength) {
+                    throw new IllegalStateException(ERROR_MSG);
                 }
+                record[i] = instance;
             }
-        }
-        for (int i = offset.length; i < record.length; ++i) {
-            byte[] rightData = right.getFieldData(i - offset.length);
-            int rightOffset = right.getFieldStart(i - offset.length);
-            bbis.setByteArray(rightData, rightOffset);
+            /** skip vertex id fields in deserialization */
+            for (int i = offset.length + 1; i < record.length; ++i) {
+                byte[] rightData = right.getFieldData(i - offset.length);
+                int rightOffset = right.getFieldStart(i - offset.length);
+                bbis.setByteArray(rightData, rightOffset);
+                int fieldLength = right.getFieldLength(i - offset.length);
 
-            Object instance = recordDescriptor.getFields()[i].deserialize(di);
-            if (LOGGER.isLoggable(Level.FINEST)) {
-                LOGGER.finest(i + " " + instance);
-            }
-            record[i] = instance;
-            if (FrameConstants.DEBUG_FRAME_IO) {
-                try {
-                    if (di.readInt() != FrameConstants.FRAME_FIELD_MAGIC) {
-                        throw new HyracksDataException("Field magic mismatch");
-                    }
-                } catch (IOException e) {
-                    e.printStackTrace();
+                int availableBefore = bbis.available();
+                Object instance = recordDescriptor.getFields()[i].deserialize(di);
+                int availableAfter = bbis.available();
+                if (availableBefore - availableAfter > fieldLength) {
+                    throw new IllegalStateException(ERROR_MSG);
                 }
+                record[i] = instance;
             }
+            return record;
+        } catch (IOException e) {
+            throw new HyracksDataException(e);
         }
-        return record;
     }
 }
diff --git a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/UpdateBuffer.java b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/UpdateBuffer.java
index b2be366..4421695 100644
--- a/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/UpdateBuffer.java
+++ b/pregelix/pregelix-dataflow-std/src/main/java/edu/uci/ics/pregelix/dataflow/util/UpdateBuffer.java
@@ -25,8 +25,10 @@
 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.FrameTupleReference;
+import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
+import edu.uci.ics.hyracks.storage.am.common.exceptions.TreeIndexNonExistentKeyException;
 
 /**
  * The buffer to hold updates.
@@ -41,6 +43,7 @@
     private final FrameTupleAppender appender;
     private final IHyracksTaskContext ctx;
     private final FrameTupleReference tuple = new FrameTupleReference();
+    private final FrameTupleReference lastTuple = new FrameTupleReference();
     private final int frameSize;
     private IFrameTupleAccessor fta;
 
@@ -94,7 +97,12 @@
             fta.reset(buffer);
             for (int j = 0; j < fta.getTupleCount(); j++) {
                 tuple.reset(fta, j);
-                bta.update(tuple);
+                try {
+                    bta.update(tuple);
+                } catch (TreeIndexNonExistentKeyException e) {
+                    // ignore non-existent key exception
+                    bta.insert(tuple);
+                }
             }
         }
 
@@ -104,6 +112,21 @@
         appender.reset(buffer, true);
     }
 
+    /**
+     * return the last updated
+     * 
+     * @throws HyracksDataException
+     */
+    public ITupleReference getLastTuple() throws HyracksDataException {
+        fta.reset(buffers.get(currentInUse));
+        int tupleIndex = fta.getTupleCount() - 1;
+        if (tupleIndex < 0) {
+            return null;
+        }
+        lastTuple.reset(fta, tupleIndex);
+        return lastTuple;
+    }
+
     private void allocate(int index) throws HyracksDataException {
         if (index >= buffers.size()) {
             buffers.add(ctx.allocateFrame());
diff --git a/pregelix/pregelix-dataflow/pom.xml b/pregelix/pregelix-dataflow/pom.xml
index ed4d9ed..1df75ae 100644
--- a/pregelix/pregelix-dataflow/pom.xml
+++ b/pregelix/pregelix-dataflow/pom.xml
@@ -16,7 +16,7 @@
 	<parent>
 		<groupId>edu.uci.ics.hyracks</groupId>
 		<artifactId>pregelix</artifactId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 	</parent>
 
 
@@ -83,75 +83,75 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>pregelix-api</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>pregelix-dataflow-std-base</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<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>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-dataflow-common</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-data-std</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-storage-am-common</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<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>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-storage-am-lsm-common</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-control-cc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-control-nc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-ipc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
diff --git a/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/ClearStateOperatorDescriptor.java b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/ClearStateOperatorDescriptor.java
new file mode 100644
index 0000000..d86557b
--- /dev/null
+++ b/pregelix/pregelix-dataflow/src/main/java/edu/uci/ics/pregelix/dataflow/ClearStateOperatorDescriptor.java
@@ -0,0 +1,82 @@
+/*
+ * 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;
+
+import edu.uci.ics.hyracks.api.comm.IFrameWriter;
+import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
+import edu.uci.ics.hyracks.api.dataflow.IOperatorNodePushable;
+import edu.uci.ics.hyracks.api.dataflow.value.IRecordDescriptorProvider;
+import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
+import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+import edu.uci.ics.hyracks.api.job.JobSpecification;
+import edu.uci.ics.hyracks.dataflow.std.base.AbstractSingleActivityOperatorDescriptor;
+import edu.uci.ics.pregelix.dataflow.context.RuntimeContext;
+
+/**
+ * Clear the state of the RuntimeContext in one slave
+ * 
+ * @author yingyib
+ */
+public class ClearStateOperatorDescriptor extends AbstractSingleActivityOperatorDescriptor {
+    private static final long serialVersionUID = 1L;
+    private String jobId;
+
+    public ClearStateOperatorDescriptor(JobSpecification spec, String jobId) {
+        super(spec, 0, 0);
+        this.jobId = jobId;
+    }
+
+    @Override
+    public IOperatorNodePushable createPushRuntime(final IHyracksTaskContext ctx,
+            IRecordDescriptorProvider recordDescProvider, int partition, int nPartitions) throws HyracksDataException {
+        return new IOperatorNodePushable() {
+
+            @Override
+            public void initialize() throws HyracksDataException {
+                RuntimeContext context = (RuntimeContext) ctx.getJobletContext().getApplicationContext()
+                        .getApplicationObject();
+                context.clearState(jobId);
+            }
+
+            @Override
+            public void deinitialize() throws HyracksDataException {
+
+            }
+
+            @Override
+            public int getInputArity() {
+                return 0;
+            }
+
+            @Override
+            public void setOutputFrameWriter(int index, IFrameWriter writer, RecordDescriptor recordDesc)
+                    throws HyracksDataException {
+
+            }
+
+            @Override
+            public IFrameWriter getInputFrameWriter(int index) {
+                return null;
+            }
+
+            @Override
+            public String getDisplayName() {
+                return "Clear State Operator";
+            }
+
+        };
+    }
+
+}
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 24a0a9e..496d066 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
@@ -56,11 +56,12 @@
     private final IBufferCache bufferCache;
     private final IVirtualBufferCache vBufferCache;
     private final IFileMapManager fileMapManager;
-    private final Map<StateKey, IStateObject> appStateMap = new ConcurrentHashMap<StateKey, IStateObject>();
-    private final Map<String, Long> giraphJobIdToSuperStep = new ConcurrentHashMap<String, Long>();
-    private final Map<String, Boolean> giraphJobIdToMove = new ConcurrentHashMap<String, Boolean>();
     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 ThreadFactory threadFactory = new ThreadFactory() {
         public Thread newThread(Runnable r) {
             return new Thread(r);
@@ -79,7 +80,7 @@
         bufferCache = new BufferCache(appCtx.getRootContext().getIOManager(), allocator, prs,
                 new PreDelayPageCleanerPolicy(Long.MAX_VALUE), fileMapManager, pageSize, numPages, 1000000,
                 threadFactory);
-        int numPagesInMemComponents = numPages / 4;
+        int numPagesInMemComponents = numPages / 8;
         vBufferCache = new MultitenantVirtualBufferCache(new VirtualBufferCache(new HeapBufferAllocator(), pageSize,
                 numPagesInMemComponents));
         ioManager = (IOManager) appCtx.getRootContext().getIOManager();
@@ -100,6 +101,18 @@
         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();
+    }
+
     public ILocalResourceRepository getLocalResourceRepository() {
         return localResourceRepository;
     }
@@ -132,14 +145,14 @@
         return (RuntimeContext) ctx.getJobletContext().getApplicationContext().getApplicationObject();
     }
 
-    public synchronized void setVertexProperties(String giraphJobId, long numVertices, long numEdges) {
-        Boolean toMove = giraphJobIdToMove.get(giraphJobId);
+    public synchronized void setVertexProperties(String jobId, long numVertices, long numEdges) {
+        Boolean toMove = jobIdToMove.get(jobId);
         if (toMove == null || toMove == true) {
-            if (giraphJobIdToSuperStep.get(giraphJobId) == null) {
-                giraphJobIdToSuperStep.put(giraphJobId, 0L);
+            if (jobIdToSuperStep.get(jobId) == null) {
+                jobIdToSuperStep.put(jobId, 0L);
             }
 
-            long superStep = giraphJobIdToSuperStep.get(giraphJobId);
+            long superStep = jobIdToSuperStep.get(jobId);
             List<FileReference> files = iterationToFiles.remove(superStep - 1);
             if (files != null) {
                 for (FileReference fileRef : files)
@@ -149,15 +162,15 @@
             Vertex.setSuperstep(++superStep);
             Vertex.setNumVertices(numVertices);
             Vertex.setNumEdges(numEdges);
-            giraphJobIdToSuperStep.put(giraphJobId, superStep);
-            giraphJobIdToMove.put(giraphJobId, false);
+            jobIdToSuperStep.put(jobId, superStep);
+            jobIdToMove.put(jobId, false);
             LOGGER.info("start iteration " + Vertex.getSuperstep());
         }
         System.gc();
     }
 
     public synchronized void endSuperStep(String giraphJobId) {
-        giraphJobIdToMove.put(giraphJobId, true);
+        jobIdToMove.put(giraphJobId, true);
         LOGGER.info("end iteration " + Vertex.getSuperstep());
     }
 
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 1d7c979..75f8ed8 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
@@ -31,6 +31,7 @@
 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;
 
@@ -91,22 +92,6 @@
         }
     }
 
-    public static void writeForceTerminationState(Configuration conf, String jobId) throws HyracksDataException {
-        try {
-            FileSystem dfs = FileSystem.get(conf);
-            String pathStr = IterationUtils.TMP_DIR + jobId + "fterm";
-            Path path = new Path(pathStr);
-            if (!dfs.exists(path)) {
-                FSDataOutputStream output = dfs.create(path, true);
-                output.writeBoolean(true);
-                output.flush();
-                output.close();
-            }
-        } catch (IOException e) {
-            throw new HyracksDataException(e);
-        }
-    }
-
     public static void writeGlobalAggregateValue(Configuration conf, String jobId, Writable agg)
             throws HyracksDataException {
         try {
@@ -136,19 +121,12 @@
         }
     }
 
+    public static void writeForceTerminationState(Configuration conf, String jobId) throws HyracksDataException {
+        JobStateUtils.writeForceTerminationState(conf, jobId);
+    }
+
     public static boolean readForceTerminationState(Configuration conf, String jobId) throws HyracksDataException {
-        try {
-            FileSystem dfs = FileSystem.get(conf);
-            String pathStr = IterationUtils.TMP_DIR + jobId + "fterm";
-            Path path = new Path(pathStr);
-            if (dfs.exists(path)) {
-                return true;
-            } else {
-                return false;
-            }
-        } catch (IOException e) {
-            throw new HyracksDataException(e);
-        }
+        return JobStateUtils.readForceTerminationState(conf, jobId);
     }
 
     public static Writable readGlobalAggregateValue(Configuration conf, String jobId) throws HyracksDataException {
diff --git a/pregelix/pregelix-dist/pom.xml b/pregelix/pregelix-dist/pom.xml
index 95ee7b5..f0551a6 100644
--- a/pregelix/pregelix-dist/pom.xml
+++ b/pregelix/pregelix-dist/pom.xml
@@ -13,7 +13,7 @@
 	<parent>
 		<groupId>edu.uci.ics.hyracks</groupId>
 		<artifactId>pregelix</artifactId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 	</parent>
 	<artifactId>pregelix-dist</artifactId>
 	<name>pregelix-dist</name>
@@ -55,13 +55,13 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>pregelix-core</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>pregelix-example</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 		</dependency>
 	</dependencies>
 </project>
diff --git a/pregelix/pregelix-example/pom.xml b/pregelix/pregelix-example/pom.xml
index 4629824..1066e3b 100644
--- a/pregelix/pregelix-example/pom.xml
+++ b/pregelix/pregelix-example/pom.xml
@@ -21,7 +21,7 @@
 	<parent>
 		<groupId>edu.uci.ics.hyracks</groupId>
 		<artifactId>pregelix</artifactId>
-		<version>0.2.9-SNAPSHOT</version>
+		<version>0.2.10-SNAPSHOT</version>
 	</parent>
 
 	<build>
@@ -107,6 +107,7 @@
 								<include>expect*</include>
 								<include>ClusterController*</include>
 								<include>edu.uci.*</include>
+								<include>dev*</include>
 							</includes>
 						</fileset>
 					</filesets>
@@ -119,7 +120,7 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>pregelix-core</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/ConnectedComponentsVertex.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/ConnectedComponentsVertex.java
index 07d2d57..a280c45 100644
--- a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/ConnectedComponentsVertex.java
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/ConnectedComponentsVertex.java
@@ -139,6 +139,7 @@
         job.setVertexOutputFormatClass(SimpleConnectedComponentsVertexOutputFormat.class);
         job.setMessageCombinerClass(ConnectedComponentsVertex.SimpleMinCombiner.class);
         job.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+        job.setDynamicVertexValueSize(true);
         Client.run(args, job);
     }
 
diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/EarlyTerminationVertex.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/EarlyTerminationVertex.java
new file mode 100644
index 0000000..e369d29
--- /dev/null
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/EarlyTerminationVertex.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.io.IOException;
+import java.util.Iterator;
+
+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.api.io.text.TextVertexOutputFormat.TextVertexWriter;
+import edu.uci.ics.pregelix.api.job.PregelixJob;
+import edu.uci.ics.pregelix.example.client.Client;
+import edu.uci.ics.pregelix.example.data.VLongNormalizedKeyComputer;
+import edu.uci.ics.pregelix.example.inputformat.TextPageRankInputFormat;
+import edu.uci.ics.pregelix.example.io.VLongWritable;
+
+/**
+ * Demonstrates the basic Pregel PageRank implementation.
+ */
+public class EarlyTerminationVertex extends Vertex<VLongWritable, VLongWritable, VLongWritable, VLongWritable> {
+    private VLongWritable tempValue = new VLongWritable();
+
+    @Override
+    public void compute(Iterator<VLongWritable> msgIterator) {
+        if (getSuperstep() == 1) {
+            if (getVertexId().get() % 4 == 2) {
+                terminatePartition();
+            } else {
+                tempValue.set(1);
+                setVertexValue(tempValue);
+            }
+        }
+        if (getSuperstep() == 2) {
+            if (getVertexId().get() % 4 == 3) {
+                terminatePartition();
+            } else {
+                tempValue.set(2);
+                setVertexValue(tempValue);
+                voteToHalt();
+            }
+        }
+    }
+
+    @Override
+    public String toString() {
+        return getVertexId() + " " + getVertexValue();
+    }
+
+    /**
+     * Simple VertexWriter that support
+     */
+    public static class SimpleEarlyTerminattionVertexWriter extends
+            TextVertexWriter<VLongWritable, VLongWritable, VLongWritable> {
+        public SimpleEarlyTerminattionVertexWriter(RecordWriter<Text, Text> lineRecordWriter) {
+            super(lineRecordWriter);
+        }
+
+        @Override
+        public void writeVertex(Vertex<VLongWritable, VLongWritable, VLongWritable, ?> vertex) throws IOException,
+                InterruptedException {
+            getRecordWriter().write(new Text(vertex.getVertexId().toString()),
+                    new Text(vertex.getVertexValue().toString()));
+        }
+    }
+
+    public static class SimpleEarlyTerminattionVertexOutputFormat extends
+            TextVertexOutputFormat<VLongWritable, VLongWritable, VLongWritable> {
+
+        @Override
+        public VertexWriter<VLongWritable, VLongWritable, VLongWritable> createVertexWriter(TaskAttemptContext context)
+                throws IOException, InterruptedException {
+            RecordWriter<Text, Text> recordWriter = textOutputFormat.getRecordWriter(context);
+            return new SimpleEarlyTerminattionVertexWriter(recordWriter);
+        }
+
+    }
+
+    public static void main(String[] args) throws Exception {
+        PregelixJob job = new PregelixJob(EarlyTerminationVertex.class.getSimpleName());
+        job.setVertexClass(EarlyTerminationVertex.class);
+        job.setVertexInputFormatClass(TextPageRankInputFormat.class);
+        job.setVertexOutputFormatClass(SimpleEarlyTerminattionVertexOutputFormat.class);
+        job.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+        job.setDynamicVertexValueSize(true);
+        Client.run(args, job);
+    }
+
+}
diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/FailureVertex.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/FailureVertex.java
new file mode 100644
index 0000000..d2464c1
--- /dev/null
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/FailureVertex.java
@@ -0,0 +1,36 @@
+/*
+ * 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 org.apache.hadoop.io.FloatWritable;
+
+import edu.uci.ics.pregelix.api.graph.Vertex;
+import edu.uci.ics.pregelix.example.io.VLongWritable;
+
+/**
+ * @author yingyib
+ */
+public class FailureVertex extends Vertex<VLongWritable, VLongWritable, FloatWritable, VLongWritable> {
+
+    @Override
+    public void compute(Iterator<VLongWritable> msgIterator) throws Exception {
+        if (getVertexId().get() == 10) {
+            throw new IllegalStateException("This job is going to fail");
+        }
+    }
+
+}
diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/GraphMutationVertex.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/GraphMutationVertex.java
index 7cf8408..7fae776 100644
--- a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/GraphMutationVertex.java
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/GraphMutationVertex.java
@@ -18,7 +18,6 @@
 import java.io.IOException;
 import java.util.Iterator;
 
-import org.apache.hadoop.io.DoubleWritable;
 import org.apache.hadoop.io.FloatWritable;
 import org.apache.hadoop.io.Text;
 import org.apache.hadoop.mapreduce.RecordWriter;
@@ -32,6 +31,7 @@
 import edu.uci.ics.pregelix.example.client.Client;
 import edu.uci.ics.pregelix.example.data.VLongNormalizedKeyComputer;
 import edu.uci.ics.pregelix.example.inputformat.TextPageRankInputFormat;
+import edu.uci.ics.pregelix.example.io.DoubleWritable;
 import edu.uci.ics.pregelix.example.io.VLongWritable;
 
 /**
diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/MessageOverflowFixedsizeVertex.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/MessageOverflowFixedsizeVertex.java
new file mode 100644
index 0000000..6c3c752
--- /dev/null
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/MessageOverflowFixedsizeVertex.java
@@ -0,0 +1,113 @@
+/*
+ * 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.Iterator;
+import java.util.Random;
+
+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.api.io.text.TextVertexOutputFormat.TextVertexWriter;
+import edu.uci.ics.pregelix.api.job.PregelixJob;
+import edu.uci.ics.pregelix.example.client.Client;
+import edu.uci.ics.pregelix.example.data.VLongNormalizedKeyComputer;
+import edu.uci.ics.pregelix.example.inputformat.TextPageRankInputFormat;
+import edu.uci.ics.pregelix.example.io.LongWritable;
+import edu.uci.ics.pregelix.example.io.VLongWritable;
+
+/**
+ * Demonstrates the basic Pregel PageRank implementation.
+ */
+public class MessageOverflowFixedsizeVertex extends Vertex<VLongWritable, LongWritable, VLongWritable, LongWritable> {
+
+    private LongWritable outputMsg = new LongWritable(1);
+    private Random rand = new Random(System.currentTimeMillis());
+    private LongWritable tmpVertexValue = new LongWritable(0);
+    private int numOfMsgClones = 10000;
+
+    @Override
+    public void compute(Iterator<LongWritable> msgIterator) {
+        if (getSuperstep() == 1) {
+            for (int i = 0; i < numOfMsgClones; i++) {
+                outputMsg.set(Math.abs(rand.nextLong()));
+                sendMsgToAllEdges(outputMsg);
+            }
+            tmpVertexValue.set(0);
+            setVertexValue(tmpVertexValue);
+        }
+        if (getSuperstep() == 2) {
+            long numOfMsg = getVertexValue().get();
+            while (msgIterator.hasNext()) {
+                msgIterator.next();
+                numOfMsg++;
+            }
+            tmpVertexValue.set(numOfMsg);
+            setVertexValue(tmpVertexValue);
+            voteToHalt();
+        }
+    }
+
+    @Override
+    public String toString() {
+        return getVertexId() + " " + getVertexValue();
+    }
+
+    /**
+     * Simple VertexWriter that support
+     */
+    public static class SimpleMessageOverflowVertexWriter extends
+            TextVertexWriter<VLongWritable, LongWritable, VLongWritable> {
+        public SimpleMessageOverflowVertexWriter(RecordWriter<Text, Text> lineRecordWriter) {
+            super(lineRecordWriter);
+        }
+
+        @Override
+        public void writeVertex(Vertex<VLongWritable, LongWritable, VLongWritable, ?> vertex) throws IOException,
+                InterruptedException {
+            getRecordWriter().write(new Text(vertex.getVertexId().toString()),
+                    new Text(vertex.getVertexValue().toString()));
+        }
+    }
+
+    public static class SimpleMessageOverflowVertexOutputFormat extends
+            TextVertexOutputFormat<VLongWritable, LongWritable, VLongWritable> {
+
+        @Override
+        public VertexWriter<VLongWritable, LongWritable, VLongWritable> createVertexWriter(TaskAttemptContext context)
+                throws IOException, InterruptedException {
+            RecordWriter<Text, Text> recordWriter = textOutputFormat.getRecordWriter(context);
+            return new SimpleMessageOverflowVertexWriter(recordWriter);
+        }
+
+    }
+
+    public static void main(String[] args) throws Exception {
+        PregelixJob job = new PregelixJob(MessageOverflowFixedsizeVertex.class.getSimpleName());
+        job.setVertexClass(MessageOverflowFixedsizeVertex.class);
+        job.setVertexInputFormatClass(TextPageRankInputFormat.class);
+        job.setVertexOutputFormatClass(SimpleMessageOverflowVertexOutputFormat.class);
+        job.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+        job.setDynamicVertexValueSize(true);
+        Client.run(args, job);
+    }
+
+}
diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/MessageOverflowVertex.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/MessageOverflowVertex.java
new file mode 100644
index 0000000..d0221bf
--- /dev/null
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/MessageOverflowVertex.java
@@ -0,0 +1,125 @@
+/*
+ * 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.Iterator;
+import java.util.Random;
+
+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.api.io.text.TextVertexOutputFormat.TextVertexWriter;
+import edu.uci.ics.pregelix.api.job.PregelixJob;
+import edu.uci.ics.pregelix.example.client.Client;
+import edu.uci.ics.pregelix.example.data.VLongNormalizedKeyComputer;
+import edu.uci.ics.pregelix.example.inputformat.TextPageRankInputFormat;
+import edu.uci.ics.pregelix.example.io.VLongWritable;
+
+/**
+ * Demonstrates the basic Pregel PageRank implementation.
+ */
+public class MessageOverflowVertex extends Vertex<VLongWritable, VLongWritable, VLongWritable, VLongWritable> {
+
+    private VLongWritable outputMsg = new VLongWritable(1);
+    private Random rand = new Random(System.currentTimeMillis());
+    private VLongWritable tmpVertexValue = new VLongWritable(0);
+    private int numOfMsgClones = 10000;
+    private int numIncomingMsgs = 0;
+
+    @Override
+    public void open() {
+        if (getSuperstep() == 2) {
+            numIncomingMsgs = 0;
+        }
+    }
+
+    @Override
+    public void compute(Iterator<VLongWritable> msgIterator) {
+        if (getSuperstep() == 1) {
+            for (int i = 0; i < numOfMsgClones; i++) {
+                outputMsg.set(Math.abs(rand.nextLong()));
+                sendMsgToAllEdges(outputMsg);
+            }
+            tmpVertexValue.set(0);
+            setVertexValue(tmpVertexValue);
+        }
+        if (getSuperstep() == 2) {
+            while (msgIterator.hasNext()) {
+                msgIterator.next();
+                numIncomingMsgs++;
+            }
+        }
+    }
+
+    @Override
+    public void close() {
+        if (getSuperstep() == 2) {
+            tmpVertexValue.set(numIncomingMsgs);
+            setVertexValue(tmpVertexValue);
+            voteToHalt();
+        }
+    }
+
+    @Override
+    public String toString() {
+        return getVertexId() + " " + getVertexValue();
+    }
+
+    /**
+     * Simple VertexWriter that support
+     */
+    public static class SimpleMessageOverflowVertexWriter extends
+            TextVertexWriter<VLongWritable, VLongWritable, VLongWritable> {
+        public SimpleMessageOverflowVertexWriter(RecordWriter<Text, Text> lineRecordWriter) {
+            super(lineRecordWriter);
+        }
+
+        @Override
+        public void writeVertex(Vertex<VLongWritable, VLongWritable, VLongWritable, ?> vertex) throws IOException,
+                InterruptedException {
+            getRecordWriter().write(new Text(vertex.getVertexId().toString()),
+                    new Text(vertex.getVertexValue().toString()));
+        }
+    }
+
+    public static class SimpleMessageOverflowVertexOutputFormat extends
+            TextVertexOutputFormat<VLongWritable, VLongWritable, VLongWritable> {
+
+        @Override
+        public VertexWriter<VLongWritable, VLongWritable, VLongWritable> createVertexWriter(TaskAttemptContext context)
+                throws IOException, InterruptedException {
+            RecordWriter<Text, Text> recordWriter = textOutputFormat.getRecordWriter(context);
+            return new SimpleMessageOverflowVertexWriter(recordWriter);
+        }
+
+    }
+
+    public static void main(String[] args) throws Exception {
+        PregelixJob job = new PregelixJob(MessageOverflowVertex.class.getSimpleName());
+        job.setVertexClass(MessageOverflowVertex.class);
+        job.setVertexInputFormatClass(TextPageRankInputFormat.class);
+        job.setVertexOutputFormatClass(SimpleMessageOverflowVertexOutputFormat.class);
+        job.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+        job.setDynamicVertexValueSize(true);
+        Client.run(args, job);
+    }
+
+}
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 8664667..a866c1c 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
@@ -21,7 +21,6 @@
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
-import org.apache.hadoop.io.DoubleWritable;
 import org.apache.hadoop.io.FloatWritable;
 import org.apache.hadoop.io.Text;
 import org.apache.hadoop.mapreduce.InputSplit;
@@ -45,6 +44,7 @@
 import edu.uci.ics.pregelix.example.client.Client;
 import edu.uci.ics.pregelix.example.data.VLongNormalizedKeyComputer;
 import edu.uci.ics.pregelix.example.inputformat.TextPageRankInputFormat;
+import edu.uci.ics.pregelix.example.io.DoubleWritable;
 import edu.uci.ics.pregelix.example.io.VLongWritable;
 
 /**
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 6a42636..1bb33b8 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
@@ -22,7 +22,6 @@
 import org.apache.hadoop.fs.FSDataOutputStream;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
-import org.apache.hadoop.io.ByteWritable;
 import org.apache.hadoop.io.FloatWritable;
 import org.apache.hadoop.io.Text;
 import org.apache.hadoop.mapreduce.RecordWriter;
@@ -42,6 +41,7 @@
 import edu.uci.ics.pregelix.example.client.Client;
 import edu.uci.ics.pregelix.example.data.VLongNormalizedKeyComputer;
 import edu.uci.ics.pregelix.example.inputformat.TextReachibilityVertexInputFormat;
+import edu.uci.ics.pregelix.example.io.ByteWritable;
 import edu.uci.ics.pregelix.example.io.VLongWritable;
 
 /**
@@ -116,7 +116,7 @@
     }
 
     @Override
-    public void compute(Iterator<ByteWritable> msgIterator) {
+    public void compute(Iterator<ByteWritable> msgIterator) throws Exception {
         if (sourceId < 0) {
             sourceId = getContext().getConfiguration().getLong(SOURCE_ID, SOURCE_ID_DEFAULT);
         }
@@ -171,13 +171,20 @@
         return getVertexId() + " " + getVertexValue();
     }
 
-    private void signalTerminate() {
-        Configuration conf = getContext().getConfiguration();
-        try {
-            IterationUtils.writeForceTerminationState(conf, BspUtils.getJobId(conf));
-            writeReachibilityResult(conf, true);
-        } catch (Exception e) {
-            throw new IllegalStateException(e);
+    private void signalTerminate() throws Exception {
+        writeReachibilityResult(getContext().getConfiguration(), true);
+        terminateJob();
+    }
+
+    private void writeReachibilityResult(Configuration conf, boolean terminate) throws IOException {
+        FileSystem dfs = FileSystem.get(conf);
+        String pathStr = IterationUtils.TMP_DIR + BspUtils.getJobId(conf) + "reachibility";
+        Path path = new Path(pathStr);
+        if (!dfs.exists(path)) {
+            FSDataOutputStream output = dfs.create(path, true);
+            output.writeBoolean(terminate);
+            output.flush();
+            output.close();
         }
     }
 
@@ -187,22 +194,6 @@
         }
     }
 
-    private void writeReachibilityResult(Configuration conf, boolean terminate) {
-        try {
-            FileSystem dfs = FileSystem.get(conf);
-            String pathStr = IterationUtils.TMP_DIR + BspUtils.getJobId(conf) + "reachibility";
-            Path path = new Path(pathStr);
-            if (!dfs.exists(path)) {
-                FSDataOutputStream output = dfs.create(path, true);
-                output.writeBoolean(terminate);
-                output.flush();
-                output.close();
-            }
-        } catch (IOException e) {
-            throw new IllegalStateException(e);
-        }
-    }
-
     private static boolean readReachibilityResult(Configuration conf) {
         try {
             FileSystem dfs = FileSystem.get(conf);
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 41c26b1..648f168 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
@@ -19,7 +19,6 @@
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
-import org.apache.hadoop.io.DoubleWritable;
 import org.apache.hadoop.io.FloatWritable;
 
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
@@ -32,6 +31,7 @@
 import edu.uci.ics.pregelix.example.client.Client;
 import edu.uci.ics.pregelix.example.data.VLongNormalizedKeyComputer;
 import edu.uci.ics.pregelix.example.inputformat.TextShortestPathsInputFormat;
+import edu.uci.ics.pregelix.example.io.DoubleWritable;
 import edu.uci.ics.pregelix.example.io.VLongWritable;
 
 /**
@@ -127,7 +127,7 @@
         }
         voteToHalt();
     }
-    
+
     @Override
     public String toString() {
         return getVertexId() + " " + getVertexValue();
diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/client/Client.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/client/Client.java
index 6cb1f4a..f99321a 100644
--- a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/client/Client.java
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/client/Client.java
@@ -16,6 +16,7 @@
 package edu.uci.ics.pregelix.example.client;
 
 import java.io.IOException;
+import java.util.List;
 
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
@@ -74,6 +75,13 @@
         driver.runJob(job, options.planChoice, options.ipAddress, options.port, Boolean.parseBoolean(options.profiling));
     }
 
+    public static void run(String[] args, List<PregelixJob> jobs) throws Exception {
+        Options options = prepareJobs(args, jobs);
+        Driver driver = new Driver(Client.class);
+        driver.runJobs(jobs, options.planChoice, options.ipAddress, options.port,
+                Boolean.parseBoolean(options.profiling));
+    }
+
     private static Options prepareJob(String[] args, PregelixJob job) throws CmdLineException, IOException {
         Options options = new Options();
         CmdLineParser parser = new CmdLineParser(options);
@@ -82,8 +90,34 @@
         String[] inputs = options.inputPaths.split(";");
         FileInputFormat.setInputPaths(job, inputs[0]);
         for (int i = 1; i < inputs.length; i++)
-            FileInputFormat.addInputPaths(job, inputs[0]);
+            FileInputFormat.addInputPaths(job, inputs[i]);
         FileOutputFormat.setOutputPath(job, new Path(options.outputPath));
+        setJobSpecificSettings(job, options);
+        return options;
+    }
+
+    private static Options prepareJobs(String[] args, List<PregelixJob> jobs) throws CmdLineException, IOException {
+        Options options = new Options();
+        CmdLineParser parser = new CmdLineParser(options);
+        parser.parseArgument(args);
+
+        for (int j = 0; j < jobs.size(); j++) {
+            PregelixJob job = jobs.get(j);
+            String[] inputs = options.inputPaths.split(";");
+            if (j == 0) {
+                FileInputFormat.setInputPaths(job, inputs[0]);
+                for (int i = 1; i < inputs.length; i++)
+                    FileInputFormat.addInputPaths(job, inputs[i]);
+            }
+            if (j == jobs.size() - 1) {
+                FileOutputFormat.setOutputPath(job, new Path(options.outputPath));
+            }
+            setJobSpecificSettings(job, options);
+        }
+        return options;
+    }
+
+    private static void setJobSpecificSettings(PregelixJob job, Options options) {
         job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, options.numVertices);
         job.getConfiguration().setLong(PregelixJob.NUM_EDGES, options.numEdges);
         job.getConfiguration().setLong(ShortestPathsVertex.SOURCE_ID, options.sourceId);
@@ -91,7 +125,6 @@
         job.getConfiguration().setLong(ReachabilityVertex.DEST_ID, options.destId);
         if (options.numIteration > 0)
             job.getConfiguration().setLong(PageRankVertex.ITERATIONS, options.numIteration);
-        return options;
     }
 
 }
diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/data/VLongNormalizedKeyComputer.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/data/VLongNormalizedKeyComputer.java
index 7d824ea..90065c2 100644
--- a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/data/VLongNormalizedKeyComputer.java
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/data/VLongNormalizedKeyComputer.java
@@ -14,8 +14,13 @@
  */
 package edu.uci.ics.pregelix.example.data;
 
+import java.io.DataInput;
+import java.io.DataInputStream;
+
+import org.apache.hadoop.io.WritableUtils;
+
 import edu.uci.ics.pregelix.api.graph.NormalizedKeyComputer;
-import edu.uci.ics.pregelix.api.util.SerDeUtils;
+import edu.uci.ics.pregelix.api.util.ResetableByteArrayInputStream;
 
 /**
  * @author yingyib
@@ -26,34 +31,42 @@
     private static final int NON_NEGATIVE_INT_MASK = (2 << 30);
     private static final int NEGATIVE_LONG_MASK = (0 << 30);
 
+    private ResetableByteArrayInputStream bis = new ResetableByteArrayInputStream();
+    private DataInput dis = new DataInputStream(bis);
+
     @Override
     public int getNormalizedKey(byte[] bytes, int start, int length) {
-        long value = SerDeUtils.readVLong(bytes, start, length);
-        int highValue = (int) (value >> 32);
-        if (highValue > 0) {
-            /**
-             * larger than Integer.MAX
-             */
-            int highNmk = getKey(highValue);
-            highNmk >>= 2;
-            highNmk |= POSTIVE_LONG_MASK;
-            return highNmk;
-        } else if (highValue == 0) {
-            /**
-             * smaller than Integer.MAX but >=0
-             */
-            int lowNmk = (int) value;
-            lowNmk >>= 2;
-            lowNmk |= NON_NEGATIVE_INT_MASK;
-            return lowNmk;
-        } else {
-            /**
-             * less than 0; TODO: have not optimized for that
-             */
-            int highNmk = getKey(highValue);
-            highNmk >>= 2;
-            highNmk |= NEGATIVE_LONG_MASK;
-            return highNmk;
+        try {
+            bis.setByteArray(bytes, start);
+            long value = WritableUtils.readVLong(dis);
+            int highValue = (int) (value >> 32);
+            if (highValue > 0) {
+                /**
+                 * larger than Integer.MAX
+                 */
+                int highNmk = getKey(highValue);
+                highNmk >>= 2;
+                highNmk |= POSTIVE_LONG_MASK;
+                return highNmk;
+            } else if (highValue == 0) {
+                /**
+                 * smaller than Integer.MAX but >=0
+                 */
+                int lowNmk = (int) value;
+                lowNmk >>= 2;
+                lowNmk |= NON_NEGATIVE_INT_MASK;
+                return lowNmk;
+            } else {
+                /**
+                 * less than 0; TODO: have not optimized for that
+                 */
+                int highNmk = getKey(highValue);
+                highNmk >>= 2;
+                highNmk |= NEGATIVE_LONG_MASK;
+                return highNmk;
+            }
+        } catch (Exception e) {
+            throw new IllegalStateException(e);
         }
     }
 
diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/inputformat/TextPageRankInputFormat.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/inputformat/TextPageRankInputFormat.java
index f46d9c3..67681d3 100644
--- a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/inputformat/TextPageRankInputFormat.java
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/inputformat/TextPageRankInputFormat.java
@@ -18,7 +18,6 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import org.apache.hadoop.io.DoubleWritable;
 import org.apache.hadoop.io.FloatWritable;
 import org.apache.hadoop.io.LongWritable;
 import org.apache.hadoop.io.Text;
@@ -31,6 +30,7 @@
 import edu.uci.ics.pregelix.api.io.text.TextVertexInputFormat;
 import edu.uci.ics.pregelix.api.io.text.TextVertexInputFormat.TextVertexReader;
 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 TextPageRankInputFormat extends
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 013a063..3ea4a9f 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
@@ -18,7 +18,6 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import org.apache.hadoop.io.DoubleWritable;
 import org.apache.hadoop.io.FloatWritable;
 import org.apache.hadoop.io.LongWritable;
 import org.apache.hadoop.io.Text;
@@ -31,6 +30,7 @@
 import edu.uci.ics.pregelix.api.io.text.TextVertexInputFormat;
 import edu.uci.ics.pregelix.api.io.text.TextVertexInputFormat.TextVertexReader;
 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 TextShortestPathsInputFormat extends
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/BooleanWritable.java
similarity index 61%
copy from hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
copy to pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/BooleanWritable.java
index cde5022..c943288 100644
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/BooleanWritable.java
@@ -12,17 +12,25 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+package edu.uci.ics.pregelix.example.io;
 
-package edu.uci.ics.hyracks.storage.am.btree.exceptions;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 
-public class BTreeDuplicateKeyException extends BTreeException {
-    private static final long serialVersionUID = 1L;
+/**
+ * Writable for Boolean values.
+ */
+public class BooleanWritable extends org.apache.hadoop.io.BooleanWritable implements WritableSizable {
 
-    public BTreeDuplicateKeyException(Exception e) {
-        super(e);
+    public BooleanWritable(boolean value) {
+        super(value);
     }
 
-    public BTreeDuplicateKeyException(String message) {
-        super(message);
+    public BooleanWritable() {
+        super();
     }
+
+    public int sizeInBytes() {
+        return 1;
+    }
+
 }
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/ByteWritable.java
similarity index 62%
copy from hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
copy to pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/ByteWritable.java
index cde5022..2a1fd22 100644
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/ByteWritable.java
@@ -12,17 +12,24 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+package edu.uci.ics.pregelix.example.io;
 
-package edu.uci.ics.hyracks.storage.am.btree.exceptions;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 
-public class BTreeDuplicateKeyException extends BTreeException {
-    private static final long serialVersionUID = 1L;
+/**
+ * Writable for Byte values.
+ */
+public class ByteWritable extends org.apache.hadoop.io.ByteWritable implements WritableSizable {
 
-    public BTreeDuplicateKeyException(Exception e) {
-        super(e);
+    public ByteWritable(byte value) {
+        super(value);
     }
 
-    public BTreeDuplicateKeyException(String message) {
-        super(message);
+    public ByteWritable() {
+        super();
+    }
+
+    public int sizeInBytes() {
+        return 1;
     }
 }
diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/BytesWritable.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/BytesWritable.java
new file mode 100644
index 0000000..04a5549
--- /dev/null
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/BytesWritable.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.pregelix.example.io;
+
+import edu.uci.ics.pregelix.api.io.WritableSizable;
+
+/**
+ * Writable for Bytes values.
+ */
+public class BytesWritable extends org.apache.hadoop.io.BytesWritable implements WritableSizable {
+
+    public BytesWritable(byte[] value) {
+        super(value);
+    }
+
+    public BytesWritable() {
+        super();
+    }
+
+    @Override
+    public int sizeInBytes() {
+        return getLength() + 4; // add the integer size slot
+    }
+
+}
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/DoubleWritable.java
similarity index 61%
copy from hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
copy to pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/DoubleWritable.java
index cde5022..ebc7fe4 100644
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/DoubleWritable.java
@@ -13,16 +13,25 @@
  * limitations under the License.
  */
 
-package edu.uci.ics.hyracks.storage.am.btree.exceptions;
+package edu.uci.ics.pregelix.example.io;
 
-public class BTreeDuplicateKeyException extends BTreeException {
-    private static final long serialVersionUID = 1L;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 
-    public BTreeDuplicateKeyException(Exception e) {
-        super(e);
+/**
+ * Writable for Double values.
+ */
+public class DoubleWritable extends org.apache.hadoop.io.DoubleWritable implements WritableSizable {
+
+    public DoubleWritable(double value) {
+        super(value);
     }
 
-    public BTreeDuplicateKeyException(String message) {
-        super(message);
+    public DoubleWritable() {
+        super();
     }
+
+    public int sizeInBytes() {
+        return 8;
+    }
+
 }
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/FloatWritable.java
similarity index 61%
copy from hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
copy to pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/FloatWritable.java
index cde5022..6772b0a 100644
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/FloatWritable.java
@@ -13,16 +13,22 @@
  * limitations under the License.
  */
 
-package edu.uci.ics.hyracks.storage.am.btree.exceptions;
+package edu.uci.ics.pregelix.example.io;
 
-public class BTreeDuplicateKeyException extends BTreeException {
-    private static final long serialVersionUID = 1L;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 
-    public BTreeDuplicateKeyException(Exception e) {
-        super(e);
+/** A WritableComparable for floats. */
+public class FloatWritable extends org.apache.hadoop.io.FloatWritable implements WritableSizable {
+
+    public FloatWritable(float value) {
+        super(value);
     }
 
-    public BTreeDuplicateKeyException(String message) {
-        super(message);
+    public FloatWritable() {
+        super();
+    }
+
+    public int sizeInBytes() {
+        return 4;
     }
 }
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/IntWritable.java
similarity index 62%
copy from hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
copy to pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/IntWritable.java
index cde5022..4944232 100644
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/IntWritable.java
@@ -13,16 +13,23 @@
  * limitations under the License.
  */
 
-package edu.uci.ics.hyracks.storage.am.btree.exceptions;
+package edu.uci.ics.pregelix.example.io;
 
-public class BTreeDuplicateKeyException extends BTreeException {
-    private static final long serialVersionUID = 1L;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 
-    public BTreeDuplicateKeyException(Exception e) {
-        super(e);
+/** A WritableComparable for ints. */
+public class IntWritable extends org.apache.hadoop.io.IntWritable implements WritableSizable {
+
+    public IntWritable(int value) {
+        super(value);
     }
 
-    public BTreeDuplicateKeyException(String message) {
-        super(message);
+    public IntWritable() {
+        super();
     }
+
+    public int sizeInBytes() {
+        return 4;
+    }
+
 }
diff --git a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/LongWritable.java
similarity index 62%
copy from hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
copy to pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/LongWritable.java
index cde5022..3ecab79 100644
--- a/hyracks/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/exceptions/BTreeDuplicateKeyException.java
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/LongWritable.java
@@ -13,16 +13,23 @@
  * limitations under the License.
  */
 
-package edu.uci.ics.hyracks.storage.am.btree.exceptions;
+package edu.uci.ics.pregelix.example.io;
 
-public class BTreeDuplicateKeyException extends BTreeException {
-    private static final long serialVersionUID = 1L;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 
-    public BTreeDuplicateKeyException(Exception e) {
-        super(e);
+/** A WritableComparable for longs. */
+public class LongWritable extends org.apache.hadoop.io.LongWritable implements WritableSizable {
+
+    public LongWritable(long value) {
+        super(value);
     }
 
-    public BTreeDuplicateKeyException(String message) {
-        super(message);
+    public LongWritable() {
+        super();
     }
+
+    public int sizeInBytes() {
+        return 8;
+    }
+
 }
diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/NullWritable.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/NullWritable.java
new file mode 100644
index 0000000..a2f184a
--- /dev/null
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/NullWritable.java
@@ -0,0 +1,89 @@
+/*
+ * 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.io;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+
+import org.apache.hadoop.io.WritableComparable;
+import org.apache.hadoop.io.WritableComparator;
+
+import edu.uci.ics.pregelix.api.io.WritableSizable;
+
+/** Singleton Writable with no data. */
+@SuppressWarnings("rawtypes")
+public class NullWritable implements WritableComparable, WritableSizable {
+
+    private static final NullWritable THIS = new NullWritable();
+
+    private NullWritable() {
+    } // no public ctor
+
+    /** Returns the single instance of this class. */
+    public static NullWritable get() {
+        return THIS;
+    }
+
+    public String toString() {
+        return "(null)";
+    }
+
+    public int sizeInBytes() {
+        return 0;
+    }
+
+    public int hashCode() {
+        return 0;
+    }
+
+    public int compareTo(Object other) {
+        if (!(other instanceof NullWritable)) {
+            throw new ClassCastException("can't compare " + other.getClass().getName() + " to NullWritable");
+        }
+        return 0;
+    }
+
+    public boolean equals(Object other) {
+        return other instanceof NullWritable;
+    }
+
+    public void readFields(DataInput in) throws IOException {
+    }
+
+    public void write(DataOutput out) throws IOException {
+    }
+
+    /** A Comparator &quot;optimized&quot; for NullWritable. */
+    public static class Comparator extends WritableComparator {
+        public Comparator() {
+            super(NullWritable.class);
+        }
+
+        /**
+         * Compare the buffers in serialized form.
+         */
+        public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
+            assert 0 == l1;
+            assert 0 == l2;
+            return 0;
+        }
+    }
+
+    static { // register this comparator
+        WritableComparator.define(NullWritable.class, new Comparator());
+    }
+}
diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/VIntWritable.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/VIntWritable.java
new file mode 100644
index 0000000..94df74f
--- /dev/null
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/VIntWritable.java
@@ -0,0 +1,89 @@
+/*
+ * 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.io;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+
+import org.apache.hadoop.io.WritableComparable;
+import org.apache.hadoop.io.WritableUtils;
+
+import edu.uci.ics.pregelix.api.io.WritableSizable;
+
+/**
+ * A WritableComparable for integer values stored in variable-length format.
+ * Such values take between one and five bytes. Smaller values take fewer bytes.
+ * 
+ * @see org.apache.hadoop.io.WritableUtils#readVInt(DataInput)
+ */
+@SuppressWarnings("rawtypes")
+public class VIntWritable implements WritableComparable, WritableSizable {
+    private int value;
+
+    public VIntWritable() {
+    }
+
+    public VIntWritable(int value) {
+        set(value);
+    }
+
+    public int sizeInBytes() {
+        return 5;
+    }
+
+    /** Set the value of this VIntWritable. */
+    public void set(int value) {
+        this.value = value;
+    }
+
+    /** Return the value of this VIntWritable. */
+    public int get() {
+        return value;
+    }
+
+    public void readFields(DataInput in) throws IOException {
+        value = WritableUtils.readVInt(in);
+    }
+
+    public void write(DataOutput out) throws IOException {
+        WritableUtils.writeVInt(out, value);
+    }
+
+    /** Returns true iff <code>o</code> is a VIntWritable with the same value. */
+    public boolean equals(Object o) {
+        if (!(o instanceof VIntWritable))
+            return false;
+        VIntWritable other = (VIntWritable) o;
+        return this.value == other.value;
+    }
+
+    public int hashCode() {
+        return value;
+    }
+
+    /** Compares two VIntWritables. */
+    public int compareTo(Object o) {
+        int thisValue = this.value;
+        int thatValue = ((VIntWritable) o).value;
+        return (thisValue < thatValue ? -1 : (thisValue == thatValue ? 0 : 1));
+    }
+
+    public String toString() {
+        return Integer.toString(value);
+    }
+
+}
diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/VLongWritable.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/VLongWritable.java
index e12d930..1c5f629 100644
--- a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/VLongWritable.java
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/io/VLongWritable.java
@@ -16,23 +16,23 @@
 package edu.uci.ics.pregelix.example.io;
 
 import java.io.DataInput;
-import java.io.DataOutput;
-import java.io.IOException;
+import java.io.DataInputStream;
 
 import org.apache.hadoop.io.WritableComparable;
 import org.apache.hadoop.io.WritableComparator;
+import org.apache.hadoop.io.WritableUtils;
 
-import edu.uci.ics.pregelix.api.util.SerDeUtils;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
+import edu.uci.ics.pregelix.api.util.ResetableByteArrayInputStream;
 
 /**
  * A WritableComparable for longs in a variable-length format. Such values take
- * between one and five bytes. Smaller values take fewer bytes.
+ * between one and nine bytes. Smaller values take fewer bytes.
  * 
  * @see org.apache.hadoop.io.WritableUtils#readVLong(DataInput)
  */
 @SuppressWarnings("rawtypes")
-public class VLongWritable implements WritableComparable {
-    private long value;
+public class VLongWritable extends org.apache.hadoop.io.VLongWritable implements WritableSizable {
 
     public VLongWritable() {
     }
@@ -41,57 +41,47 @@
         set(value);
     }
 
-    /** Set the value of this LongWritable. */
-    public void set(long value) {
-        this.value = value;
-    }
+    public int sizeInBytes() {
+        long i = get();
+        if (i >= -112 && i <= 127) {
+            return 1;
+        }
 
-    /** Return the value of this LongWritable. */
-    public long get() {
-        return value;
-    }
+        int len = -112;
+        if (i < 0) {
+            i ^= -1L; // take one's complement'
+            len = -120;
+        }
 
-    public void readFields(DataInput in) throws IOException {
-        value = SerDeUtils.readVLong(in);
-    }
+        long tmp = i;
+        while (tmp != 0) {
+            tmp = tmp >> 8;
+            len--;
+        }
 
-    public void write(DataOutput out) throws IOException {
-        SerDeUtils.writeVLong(out, value);
-    }
-
-    /** Returns true iff <code>o</code> is a VLongWritable with the same value. */
-    public boolean equals(Object o) {
-        if (!(o instanceof VLongWritable))
-            return false;
-        VLongWritable other = (VLongWritable) o;
-        return this.value == other.value;
-    }
-
-    public int hashCode() {
-        return (int) value;
-    }
-
-    /** Compares two VLongWritables. */
-    public int compareTo(Object o) {
-        long thisValue = this.value;
-        long thatValue = ((VLongWritable) o).value;
-        return (thisValue < thatValue ? -1 : (thisValue == thatValue ? 0 : 1));
-    }
-
-    public String toString() {
-        return Long.toString(value);
+        len = (len < -120) ? -(len + 120) : -(len + 112);
+        return len + 1;
     }
 
     /** A Comparator optimized for LongWritable. */
     public static class Comparator extends WritableComparator {
+        private ResetableByteArrayInputStream bis = new ResetableByteArrayInputStream();
+        private DataInput dis = new DataInputStream(bis);
+
         public Comparator() {
             super(VLongWritable.class);
         }
 
         public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
-            long thisValue = SerDeUtils.readVLong(b1, s1, l1);
-            long thatValue = SerDeUtils.readVLong(b2, s2, l2);
-            return (thisValue < thatValue ? -1 : (thisValue == thatValue ? 0 : 1));
+            try {
+                bis.setByteArray(b1, s1);
+                long thisValue = WritableUtils.readVLong(dis);
+                bis.setByteArray(b2, s2);
+                long thatValue = WritableUtils.readVLong(dis);
+                return (thisValue < thatValue ? -1 : (thisValue == thatValue ? 0 : 1));
+            } catch (Exception e) {
+                throw new IllegalStateException(e);
+            }
         }
     }
 
diff --git a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/maximalclique/AdjacencyListWritable.java b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/maximalclique/AdjacencyListWritable.java
index 0a58c00..dd86a45 100644
--- a/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/maximalclique/AdjacencyListWritable.java
+++ b/pregelix/pregelix-example/src/main/java/edu/uci/ics/pregelix/example/maximalclique/AdjacencyListWritable.java
@@ -23,14 +23,13 @@
 import java.util.Set;
 import java.util.TreeSet;
 
-import org.apache.hadoop.io.Writable;
-
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 import edu.uci.ics.pregelix.example.io.VLongWritable;
 
 /**
  * The adjacency list contains <src, list-of-neighbors>
  */
-public class AdjacencyListWritable implements Writable {
+public class AdjacencyListWritable implements WritableSizable {
 
     private VLongWritable sourceVertex = new VLongWritable();
     private Set<VLongWritable> destinationVertexes = new TreeSet<VLongWritable>();
@@ -96,4 +95,13 @@
         return destinationVertexes.contains(v);
     }
 
+    @Override
+    public int sizeInBytes() {
+        int size = 4; // the size of list bytes
+        for (VLongWritable dest : destinationVertexes) {
+            size += dest.sizeInBytes();
+        }
+        return size;
+    }
+
 }
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 670620f..cb7fd6d 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
@@ -26,8 +26,13 @@
 import edu.uci.ics.pregelix.api.util.DefaultVertexPartitioner;
 import edu.uci.ics.pregelix.example.ConnectedComponentsVertex;
 import edu.uci.ics.pregelix.example.ConnectedComponentsVertex.SimpleConnectedComponentsVertexOutputFormat;
+import edu.uci.ics.pregelix.example.EarlyTerminationVertex;
+import edu.uci.ics.pregelix.example.EarlyTerminationVertex.SimpleEarlyTerminattionVertexOutputFormat;
 import edu.uci.ics.pregelix.example.GraphMutationVertex;
 import edu.uci.ics.pregelix.example.GraphMutationVertex.SimpleGraphMutationVertexOutputFormat;
+import edu.uci.ics.pregelix.example.MessageOverflowFixedsizeVertex;
+import edu.uci.ics.pregelix.example.MessageOverflowVertex;
+import edu.uci.ics.pregelix.example.MessageOverflowVertex.SimpleMessageOverflowVertexOutputFormat;
 import edu.uci.ics.pregelix.example.PageRankVertex;
 import edu.uci.ics.pregelix.example.PageRankVertex.SimplePageRankVertexOutputFormat;
 import edu.uci.ics.pregelix.example.PageRankVertex.SimulatedPageRankVertexInputFormat;
@@ -121,6 +126,7 @@
         job.setVertexOutputFormatClass(SimpleConnectedComponentsVertexOutputFormat.class);
         job.setMessageCombinerClass(ConnectedComponentsVertex.SimpleMinCombiner.class);
         job.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+        job.setDynamicVertexValueSize(true);
         FileInputFormat.setInputPaths(job, HDFS_INPUTPATH);
         FileOutputFormat.setOutputPath(job, new Path(HDFS_OUTPUTPAH));
         job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 20);
@@ -135,6 +141,7 @@
         job.setMessageCombinerClass(ConnectedComponentsVertex.SimpleMinCombiner.class);
         job.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
         job.setVertexPartitionerClass(DefaultVertexPartitioner.class);
+        job.setDynamicVertexValueSize(true);
         FileInputFormat.setInputPaths(job, HDFS_INPUTPATH2);
         FileOutputFormat.setOutputPath(job, new Path(HDFS_OUTPUTPAH2));
         job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 23);
@@ -280,6 +287,59 @@
         job.getConfiguration().writeXml(new FileOutputStream(new File(outputPath)));
     }
 
+    private static void generateMessageOverflowFixedsizeJob(String jobName, String outputPath) throws IOException {
+        PregelixJob job = new PregelixJob(jobName);
+        job.setVertexClass(MessageOverflowFixedsizeVertex.class);
+        job.setVertexInputFormatClass(TextPageRankInputFormat.class);
+        job.setVertexOutputFormatClass(MessageOverflowFixedsizeVertex.SimpleMessageOverflowVertexOutputFormat.class);
+        job.setFrameSize(2048);
+        FileInputFormat.setInputPaths(job, HDFS_INPUTPATH);
+        FileOutputFormat.setOutputPath(job, new Path(HDFS_OUTPUTPAH));
+        job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 20);
+        job.getConfiguration().writeXml(new FileOutputStream(new File(outputPath)));
+    }
+
+    private static void generateMessageOverflowJob(String jobName, String outputPath) throws IOException {
+        PregelixJob job = new PregelixJob(jobName);
+        job.setVertexClass(MessageOverflowVertex.class);
+        job.setVertexInputFormatClass(TextPageRankInputFormat.class);
+        job.setVertexOutputFormatClass(SimpleMessageOverflowVertexOutputFormat.class);
+        job.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+        job.setDynamicVertexValueSize(true);
+        job.setFrameSize(2048);
+        FileInputFormat.setInputPaths(job, HDFS_INPUTPATH);
+        FileOutputFormat.setOutputPath(job, new Path(HDFS_OUTPUTPAH));
+        job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 20);
+        job.getConfiguration().writeXml(new FileOutputStream(new File(outputPath)));
+    }
+
+    private static void generateMessageOverflowJobLSM(String jobName, String outputPath) throws IOException {
+        PregelixJob job = new PregelixJob(jobName);
+        job.setVertexClass(MessageOverflowVertex.class);
+        job.setVertexInputFormatClass(TextPageRankInputFormat.class);
+        job.setVertexOutputFormatClass(SimpleMessageOverflowVertexOutputFormat.class);
+        job.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+        job.setDynamicVertexValueSize(true);
+        job.setFrameSize(2048);
+        job.setLSMStorage(true);
+        FileInputFormat.setInputPaths(job, HDFS_INPUTPATH);
+        FileOutputFormat.setOutputPath(job, new Path(HDFS_OUTPUTPAH));
+        job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 20);
+        job.getConfiguration().writeXml(new FileOutputStream(new File(outputPath)));
+    }
+
+    private static void generateEarlyTerminationJob(String jobName, String outputPath) throws IOException {
+        PregelixJob job = new PregelixJob(jobName);
+        job.setVertexClass(EarlyTerminationVertex.class);
+        job.setVertexInputFormatClass(TextPageRankInputFormat.class);
+        job.setVertexOutputFormatClass(SimpleEarlyTerminattionVertexOutputFormat.class);
+        job.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+        FileInputFormat.setInputPaths(job, HDFS_INPUTPATH);
+        FileOutputFormat.setOutputPath(job, new Path(HDFS_OUTPUTPAH));
+        job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 20);
+        job.getConfiguration().writeXml(new FileOutputStream(new File(outputPath)));
+    }
+
     private static void genPageRank() throws IOException {
         generatePageRankJob("PageRank", outputBase + "PageRank.xml");
         generatePageRankJobReal("PageRank", outputBase + "PageRankReal.xml");
@@ -319,6 +379,16 @@
         generateGraphMutationJob("Graph Mutation", outputBase + "GraphMutation.xml");
     }
 
+    private static void genMessageOverflow() throws IOException {
+        generateMessageOverflowJob("Message Overflow", outputBase + "MessageOverflow.xml");
+        generateMessageOverflowJobLSM("Message Overflow LSM", outputBase + "MessageOverflowLSM.xml");
+        generateMessageOverflowFixedsizeJob("Message Overflow Fixedsize", outputBase + "MessageOverflowFixedsize.xml");
+    }
+
+    private static void genEarlyTermination() throws IOException {
+        generateEarlyTerminationJob("Early Termination", outputBase + "EarlyTermination.xml");
+    }
+
     public static void main(String[] args) throws IOException {
         genPageRank();
         genShortestPath();
@@ -327,5 +397,7 @@
         genTriangleCounting();
         genMaximalClique();
         genGraphMutation();
+        genMessageOverflow();
+        genEarlyTermination();
     }
 }
diff --git a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/lib/io/SizeEstimationTest.java b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/lib/io/SizeEstimationTest.java
new file mode 100644
index 0000000..638011b
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/lib/io/SizeEstimationTest.java
@@ -0,0 +1,176 @@
+/*
+ * 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.lib.io;
+
+import java.io.ByteArrayOutputStream;
+import java.io.DataOutput;
+import java.io.DataOutputStream;
+import java.util.Random;
+
+import org.junit.Test;
+
+import edu.uci.ics.pregelix.api.graph.MsgList;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
+import edu.uci.ics.pregelix.example.io.BooleanWritable;
+import edu.uci.ics.pregelix.example.io.ByteWritable;
+import edu.uci.ics.pregelix.example.io.DoubleWritable;
+import edu.uci.ics.pregelix.example.io.IntWritable;
+import edu.uci.ics.pregelix.example.io.LongWritable;
+import edu.uci.ics.pregelix.example.io.NullWritable;
+import edu.uci.ics.pregelix.example.io.VIntWritable;
+import edu.uci.ics.pregelix.example.io.VLongWritable;
+
+/**
+ * @author yingyib
+ */
+public class SizeEstimationTest {
+
+    @Test
+    public void testVLong() throws Exception {
+        Random rand = new Random(System.currentTimeMillis());
+        MsgList<WritableSizable> msgList = new MsgList<WritableSizable>();
+        msgList.add(new VLongWritable(Long.MAX_VALUE));
+        msgList.add(new VLongWritable(Long.MIN_VALUE));
+        msgList.add(new VLongWritable(-1));
+        for (int i = 0; i < 1000000; i++) {
+            msgList.add(new VLongWritable(Math.abs(rand.nextLong())));
+        }
+        verifyExactSizeEstimation(msgList);
+    }
+
+    @Test
+    public void testLong() throws Exception {
+        Random rand = new Random(System.currentTimeMillis());
+        MsgList<WritableSizable> msgList = new MsgList<WritableSizable>();
+        for (int i = 0; i < 1000000; i++) {
+            msgList.add(new LongWritable(rand.nextLong()));
+        }
+        verifySizeEstimation(msgList);
+    }
+
+    @Test
+    public void testBoolean() throws Exception {
+        Random rand = new Random(System.currentTimeMillis());
+        MsgList<WritableSizable> msgList = new MsgList<WritableSizable>();
+        for (int i = 0; i < 1000000; i++) {
+            msgList.add(new BooleanWritable(rand.nextBoolean()));
+        }
+        verifySizeEstimation(msgList);
+    }
+
+    @Test
+    public void testByte() throws Exception {
+        Random rand = new Random(System.currentTimeMillis());
+        MsgList<WritableSizable> msgList = new MsgList<WritableSizable>();
+        for (int i = 0; i < 1000000; i++) {
+            msgList.add(new ByteWritable((byte) rand.nextInt()));
+        }
+        verifySizeEstimation(msgList);
+    }
+
+    @Test
+    public void testDouble() throws Exception {
+        Random rand = new Random(System.currentTimeMillis());
+        MsgList<WritableSizable> msgList = new MsgList<WritableSizable>();
+        for (int i = 0; i < 1000000; i++) {
+            msgList.add(new DoubleWritable(rand.nextDouble()));
+        }
+        verifySizeEstimation(msgList);
+    }
+
+    @Test
+    public void testFloat() throws Exception {
+        Random rand = new Random(System.currentTimeMillis());
+        MsgList<WritableSizable> msgList = new MsgList<WritableSizable>();
+        for (int i = 0; i < 1000000; i++) {
+            msgList.add(new DoubleWritable(rand.nextFloat()));
+        }
+        verifySizeEstimation(msgList);
+    }
+
+    @Test
+    public void testNull() throws Exception {
+        MsgList<WritableSizable> msgList = new MsgList<WritableSizable>();
+        for (int i = 0; i < 1000000; i++) {
+            msgList.add(NullWritable.get());
+        }
+        verifySizeEstimation(msgList);
+    }
+
+    @Test
+    public void testVInt() throws Exception {
+        Random rand = new Random(System.currentTimeMillis());
+        MsgList<WritableSizable> msgList = new MsgList<WritableSizable>();
+        for (int i = 0; i < 1000000; i++) {
+            msgList.add(new VIntWritable(rand.nextInt()));
+        }
+        verifySizeEstimation(msgList);
+    }
+
+    @Test
+    public void testInt() throws Exception {
+        Random rand = new Random(System.currentTimeMillis());
+        MsgList<WritableSizable> msgList = new MsgList<WritableSizable>();
+        for (int i = 0; i < 1000000; i++) {
+            msgList.add(new IntWritable(rand.nextInt()));
+        }
+        verifySizeEstimation(msgList);
+    }
+
+    private void verifySizeEstimation(MsgList<WritableSizable> msgList) throws Exception {
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        DataOutput dos = new DataOutputStream(bos);
+        int accumulatedSize = 5;
+        for (int i = 0; i < msgList.size(); i++) {
+            bos.reset();
+            WritableSizable value = msgList.get(i);
+            value.write(dos);
+            if (value.sizeInBytes() < bos.size()) {
+                throw new Exception(value + " estimated size (" + value.sizeInBytes()
+                        + ") is smaller than the actual size" + bos.size());
+            }
+            accumulatedSize += value.sizeInBytes();
+        }
+        bos.reset();
+        msgList.write(dos);
+        if (accumulatedSize < bos.size()) {
+            throw new Exception("Estimated list size (" + accumulatedSize + ") is smaller than the actual size"
+                    + bos.size());
+        }
+    }
+
+    private void verifyExactSizeEstimation(MsgList<WritableSizable> msgList) throws Exception {
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        DataOutput dos = new DataOutputStream(bos);
+        int accumulatedSize = 5;
+        for (int i = 0; i < msgList.size(); i++) {
+            bos.reset();
+            WritableSizable value = msgList.get(i);
+            value.write(dos);
+            if (value.sizeInBytes() != bos.size()) {
+                throw new Exception(value + " estimated size (" + value.sizeInBytes()
+                        + ") is smaller than the actual size" + bos.size());
+            }
+            accumulatedSize += value.sizeInBytes();
+        }
+        bos.reset();
+        msgList.write(dos);
+        if (accumulatedSize < bos.size()) {
+            throw new Exception("Estimated list size (" + accumulatedSize + ") is smaller than the actual size"
+                    + bos.size());
+        }
+    }
+
+}
diff --git a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/test/FailureVertexTest.java b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/test/FailureVertexTest.java
new file mode 100644
index 0000000..aa0dfdd
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/test/FailureVertexTest.java
@@ -0,0 +1,69 @@
+/*
+ * 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.test;
+
+import junit.framework.Assert;
+
+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.driver.Driver;
+import edu.uci.ics.pregelix.core.util.PregelixHyracksIntegrationUtil;
+import edu.uci.ics.pregelix.example.ConnectedComponentsVertex;
+import edu.uci.ics.pregelix.example.ConnectedComponentsVertex.SimpleConnectedComponentsVertexOutputFormat;
+import edu.uci.ics.pregelix.example.FailureVertex;
+import edu.uci.ics.pregelix.example.data.VLongNormalizedKeyComputer;
+import edu.uci.ics.pregelix.example.inputformat.TextPageRankInputFormat;
+
+/**
+ * This test case tests the error message propagation.
+ * 
+ * @author yingyib
+ */
+public class FailureVertexTest {
+
+    private static String HDFS_INPUTPATH2 = "data/webmapcomplex";
+    private static String HDFS_OUTPUTPAH2 = "actual/resultcomplex";
+
+    @Test
+    public void test() throws Exception {
+        TestCluster testCluster = new TestCluster();
+        try {
+            PregelixJob job = new PregelixJob(FailureVertex.class.getSimpleName());
+            job.setVertexClass(FailureVertex.class);
+            job.setVertexInputFormatClass(TextPageRankInputFormat.class);
+            job.setVertexOutputFormatClass(SimpleConnectedComponentsVertexOutputFormat.class);
+            job.setMessageCombinerClass(ConnectedComponentsVertex.SimpleMinCombiner.class);
+            job.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+            job.setDynamicVertexValueSize(true);
+
+            FileInputFormat.setInputPaths(job, HDFS_INPUTPATH2);
+            FileOutputFormat.setOutputPath(job, new Path(HDFS_OUTPUTPAH2));
+            job.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 23);
+
+            Driver driver = new Driver(FailureVertex.class);
+            testCluster.setUp();
+            driver.runJob(job, "127.0.0.1", PregelixHyracksIntegrationUtil.TEST_HYRACKS_CC_CLIENT_PORT);
+        } catch (Exception e) {
+            Assert.assertTrue(e.toString().contains("This job is going to fail"));
+        } finally {
+            testCluster.tearDown();
+        }
+    }
+
+}
diff --git a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/test/JobConcatenationTest.java b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/test/JobConcatenationTest.java
new file mode 100644
index 0000000..0d6f863
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/test/JobConcatenationTest.java
@@ -0,0 +1,83 @@
+/*
+ * 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.test;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
+
+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.driver.Driver;
+import edu.uci.ics.pregelix.core.util.PregelixHyracksIntegrationUtil;
+import edu.uci.ics.pregelix.example.PageRankVertex;
+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.TestUtils;
+
+/**
+ * @author yingyib
+ */
+public class JobConcatenationTest {
+
+    private static String INPUTPATH = "data/webmap";
+    private static String OUTPUTPAH = "actual/result";
+    private static String EXPECTEDPATH = "src/test/resources/expected/PageRankReal";
+
+    @Test
+    public void test() throws Exception {
+        TestCluster testCluster = new TestCluster();
+
+        try {
+            List<PregelixJob> jobs = new ArrayList<PregelixJob>();
+            PregelixJob job1 = new PregelixJob(PageRankVertex.class.getName());
+            job1.setVertexClass(PageRankVertex.class);
+            job1.setVertexInputFormatClass(TextPageRankInputFormat.class);
+            job1.setVertexOutputFormatClass(SimplePageRankVertexOutputFormat.class);
+            job1.setMessageCombinerClass(PageRankVertex.SimpleSumCombiner.class);
+            job1.setNoramlizedKeyComputerClass(VLongNormalizedKeyComputer.class);
+            FileInputFormat.setInputPaths(job1, INPUTPATH);
+            job1.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 20);
+
+            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);
+            FileOutputFormat.setOutputPath(job2, new Path(OUTPUTPAH));
+            job2.getConfiguration().setLong(PregelixJob.NUM_VERTICE, 20);
+
+            jobs.add(job1);
+            jobs.add(job2);
+
+            testCluster.setUp();
+            Driver driver = new Driver(PageRankVertex.class);
+            driver.runJobs(jobs, "127.0.0.1", PregelixHyracksIntegrationUtil.TEST_HYRACKS_CC_CLIENT_PORT);
+
+            TestUtils.compareWithResultDir(new File(EXPECTEDPATH), new File(OUTPUTPAH));
+        } catch (Exception e) {
+            throw e;
+        } finally {
+            testCluster.tearDown();
+        }
+    }
+
+}
diff --git a/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/test/TestCluster.java b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/test/TestCluster.java
new file mode 100644
index 0000000..d0cf654
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/java/edu/uci/ics/pregelix/example/test/TestCluster.java
@@ -0,0 +1,150 @@
+/*
+ * 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.test;
+
+import java.io.BufferedReader;
+import java.io.DataOutputStream;
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.logging.Logger;
+
+import org.apache.commons.io.FileUtils;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hdfs.MiniDFSCluster;
+import org.apache.hadoop.mapred.JobConf;
+
+import edu.uci.ics.pregelix.core.jobgen.clusterconfig.ClusterConfig;
+import edu.uci.ics.pregelix.core.util.PregelixHyracksIntegrationUtil;
+
+@SuppressWarnings("deprecation")
+public class TestCluster {
+    private static final Logger LOGGER = Logger.getLogger(TestCluster.class.getName());
+
+    private static final String ACTUAL_RESULT_DIR = "actual";
+    private static final String PATH_TO_HADOOP_CONF = "src/test/resources/hadoop/conf";
+    private static final String PATH_TO_CLUSTER_STORE = "src/test/resources/cluster/stores.properties";
+    private static final String PATH_TO_CLUSTER_PROPERTIES = "src/test/resources/cluster/cluster.properties";
+
+    private static final String DATA_PATH = "data/webmap/webmap_link.txt";
+    private static final String HDFS_PATH = "/webmap/";
+
+    private static final String DATA_PATH2 = "data/webmapcomplex/webmap_link.txt";
+    private static final String HDFS_PATH2 = "/webmapcomplex/";
+
+    private static final String DATA_PATH3 = "data/clique/clique.txt";
+    private static final String HDFS_PATH3 = "/clique/";
+
+    private static final String DATA_PATH4 = "data/clique2/clique.txt";
+    private static final String HDFS_PATH4 = "/clique2/";
+
+    private static final String DATA_PATH5 = "data/clique3/clique.txt";
+    private static final String HDFS_PATH5 = "/clique3/";
+
+    private static final String HADOOP_CONF_PATH = ACTUAL_RESULT_DIR + File.separator + "conf.xml";
+    private MiniDFSCluster dfsCluster;
+
+    private JobConf conf = new JobConf();
+    private int numberOfNC = 2;
+
+    public void setUp() throws Exception {
+        ClusterConfig.setStorePath(PATH_TO_CLUSTER_STORE);
+        ClusterConfig.setClusterPropertiesPath(PATH_TO_CLUSTER_PROPERTIES);
+        cleanupStores();
+        PregelixHyracksIntegrationUtil.init();
+        LOGGER.info("Hyracks mini-cluster started");
+        FileUtils.forceMkdir(new File(ACTUAL_RESULT_DIR));
+        FileUtils.cleanDirectory(new File(ACTUAL_RESULT_DIR));
+        startHDFS();
+    }
+
+    private void cleanupStores() throws IOException {
+        FileUtils.forceMkdir(new File("teststore"));
+        FileUtils.forceMkdir(new File("build"));
+        FileUtils.cleanDirectory(new File("teststore"));
+        FileUtils.cleanDirectory(new File("build"));
+    }
+
+    private void startHDFS() throws IOException {
+        conf.addResource(new Path(PATH_TO_HADOOP_CONF + "/core-site.xml"));
+        conf.addResource(new Path(PATH_TO_HADOOP_CONF + "/mapred-site.xml"));
+        conf.addResource(new Path(PATH_TO_HADOOP_CONF + "/hdfs-site.xml"));
+        FileSystem lfs = FileSystem.getLocal(new Configuration());
+        lfs.delete(new Path("build"), true);
+        System.setProperty("hadoop.log.dir", "logs");
+        dfsCluster = new MiniDFSCluster(conf, numberOfNC, true, null);
+        FileSystem dfs = FileSystem.get(conf);
+        Path src = new Path(DATA_PATH);
+        Path dest = new Path(HDFS_PATH);
+        dfs.mkdirs(dest);
+        dfs.copyFromLocalFile(src, dest);
+
+        src = new Path(DATA_PATH2);
+        dest = new Path(HDFS_PATH2);
+        dfs.mkdirs(dest);
+        dfs.copyFromLocalFile(src, dest);
+
+        src = new Path(DATA_PATH3);
+        dest = new Path(HDFS_PATH3);
+        dfs.mkdirs(dest);
+        dfs.copyFromLocalFile(src, dest);
+
+        src = new Path(DATA_PATH4);
+        dest = new Path(HDFS_PATH4);
+        dfs.mkdirs(dest);
+        dfs.copyFromLocalFile(src, dest);
+
+        src = new Path(DATA_PATH5);
+        dest = new Path(HDFS_PATH5);
+        dfs.mkdirs(dest);
+        dfs.copyFromLocalFile(src, dest);
+
+        DataOutputStream confOutput = new DataOutputStream(new FileOutputStream(new File(HADOOP_CONF_PATH)));
+        conf.writeXml(confOutput);
+        confOutput.flush();
+        confOutput.close();
+    }
+
+    /**
+     * cleanup hdfs cluster
+     */
+    private void cleanupHDFS() throws Exception {
+        dfsCluster.shutdown();
+    }
+
+    public void tearDown() throws Exception {
+        PregelixHyracksIntegrationUtil.deinit();
+        LOGGER.info("Hyracks mini-cluster shut down");
+        cleanupHDFS();
+    }
+
+    protected static List<String> getFileList(String ignorePath) throws FileNotFoundException, IOException {
+        BufferedReader reader = new BufferedReader(new FileReader(ignorePath));
+        String s = null;
+        List<String> ignores = new ArrayList<String>();
+        while ((s = reader.readLine()) != null) {
+            ignores.add(s);
+        }
+        reader.close();
+        return ignores;
+    }
+
+}
diff --git a/pregelix/pregelix-example/src/test/resources/expected/EarlyTermination/part-0 b/pregelix/pregelix-example/src/test/resources/expected/EarlyTermination/part-0
new file mode 100644
index 0000000..60a55af
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/expected/EarlyTermination/part-0
@@ -0,0 +1,5 @@
+0	2
+4	2
+8	2
+12	2
+16	2
diff --git a/pregelix/pregelix-example/src/test/resources/expected/EarlyTermination/part-1 b/pregelix/pregelix-example/src/test/resources/expected/EarlyTermination/part-1
new file mode 100644
index 0000000..32ee93f
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/expected/EarlyTermination/part-1
@@ -0,0 +1,5 @@
+1	2
+5	2
+9	2
+13	2
+17	2
diff --git a/pregelix/pregelix-example/src/test/resources/expected/EarlyTermination/part-2 b/pregelix/pregelix-example/src/test/resources/expected/EarlyTermination/part-2
new file mode 100644
index 0000000..542ccae
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/expected/EarlyTermination/part-2
@@ -0,0 +1,5 @@
+2	0
+6	0
+10	0
+14	0
+18	0
diff --git a/pregelix/pregelix-example/src/test/resources/expected/EarlyTermination/part-3 b/pregelix/pregelix-example/src/test/resources/expected/EarlyTermination/part-3
new file mode 100644
index 0000000..ff0e5b8
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/expected/EarlyTermination/part-3
@@ -0,0 +1,5 @@
+3	1
+7	1
+11	1
+15	1
+19	1
diff --git a/pregelix/pregelix-example/src/test/resources/expected/MessageOverflow/part-0 b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflow/part-0
new file mode 100644
index 0000000..db5f679
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflow/part-0
@@ -0,0 +1,5 @@
+0	10000
+4	70000
+8	30000
+12	90000
+16	50000
diff --git a/pregelix/pregelix-example/src/test/resources/expected/MessageOverflow/part-1 b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflow/part-1
new file mode 100644
index 0000000..3dc4629
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflow/part-1
@@ -0,0 +1,5 @@
+1	100000
+5	60000
+9	20000
+13	80000
+17	40000
diff --git a/pregelix/pregelix-example/src/test/resources/expected/MessageOverflow/part-2 b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflow/part-2
new file mode 100644
index 0000000..bc95831
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflow/part-2
@@ -0,0 +1,5 @@
+2	90000
+6	50000
+10	10000
+14	70000
+18	30000
diff --git a/pregelix/pregelix-example/src/test/resources/expected/MessageOverflow/part-3 b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflow/part-3
new file mode 100644
index 0000000..b619cd7
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflow/part-3
@@ -0,0 +1,5 @@
+3	80000
+7	40000
+11	100000
+15	60000
+19	20000
diff --git a/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowFixedsize/part-0 b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowFixedsize/part-0
new file mode 100644
index 0000000..db5f679
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowFixedsize/part-0
@@ -0,0 +1,5 @@
+0	10000
+4	70000
+8	30000
+12	90000
+16	50000
diff --git a/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowFixedsize/part-1 b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowFixedsize/part-1
new file mode 100644
index 0000000..3dc4629
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowFixedsize/part-1
@@ -0,0 +1,5 @@
+1	100000
+5	60000
+9	20000
+13	80000
+17	40000
diff --git a/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowFixedsize/part-2 b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowFixedsize/part-2
new file mode 100644
index 0000000..bc95831
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowFixedsize/part-2
@@ -0,0 +1,5 @@
+2	90000
+6	50000
+10	10000
+14	70000
+18	30000
diff --git a/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowFixedsize/part-3 b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowFixedsize/part-3
new file mode 100644
index 0000000..b619cd7
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowFixedsize/part-3
@@ -0,0 +1,5 @@
+3	80000
+7	40000
+11	100000
+15	60000
+19	20000
diff --git a/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowLSM/part-0 b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowLSM/part-0
new file mode 100644
index 0000000..db5f679
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowLSM/part-0
@@ -0,0 +1,5 @@
+0	10000
+4	70000
+8	30000
+12	90000
+16	50000
diff --git a/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowLSM/part-1 b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowLSM/part-1
new file mode 100644
index 0000000..3dc4629
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowLSM/part-1
@@ -0,0 +1,5 @@
+1	100000
+5	60000
+9	20000
+13	80000
+17	40000
diff --git a/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowLSM/part-2 b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowLSM/part-2
new file mode 100644
index 0000000..bc95831
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowLSM/part-2
@@ -0,0 +1,5 @@
+2	90000
+6	50000
+10	10000
+14	70000
+18	30000
diff --git a/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowLSM/part-3 b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowLSM/part-3
new file mode 100644
index 0000000..b619cd7
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/expected/MessageOverflowLSM/part-3
@@ -0,0 +1,5 @@
+3	80000
+7	40000
+11	100000
+15	60000
+19	20000
diff --git a/pregelix/pregelix-example/src/test/resources/jobs/ConnectedComponentsReal.xml b/pregelix/pregelix-example/src/test/resources/jobs/ConnectedComponentsReal.xml
index decbde8..df72d9b 100644
--- a/pregelix/pregelix-example/src/test/resources/jobs/ConnectedComponentsReal.xml
+++ b/pregelix/pregelix-example/src/test/resources/jobs/ConnectedComponentsReal.xml
@@ -127,6 +127,7 @@
 <property><name>pregelix.vertexInputFormatClass</name><value>edu.uci.ics.pregelix.example.inputformat.TextConnectedComponentsInputFormat</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>true</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/ConnectedComponentsRealComplex.xml b/pregelix/pregelix-example/src/test/resources/jobs/ConnectedComponentsRealComplex.xml
index cca66bb..b0bf024 100644
--- a/pregelix/pregelix-example/src/test/resources/jobs/ConnectedComponentsRealComplex.xml
+++ b/pregelix/pregelix-example/src/test/resources/jobs/ConnectedComponentsRealComplex.xml
@@ -128,6 +128,7 @@
 <property><name>pregelix.vertexInputFormatClass</name><value>edu.uci.ics.pregelix.example.inputformat.TextConnectedComponentsInputFormat</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>true</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/EarlyTermination.xml b/pregelix/pregelix-example/src/test/resources/jobs/EarlyTermination.xml
new file mode 100644
index 0000000..d908da8
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/jobs/EarlyTermination.xml
@@ -0,0 +1,142 @@
+<?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:/webmap</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>/result</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>Early Termination</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>20</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.EarlyTerminationVertex</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>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>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>${hadoop.tmp.dir}/mapred/system</value></property>
+<property><name>mapred.line.input.format.linespermap</name><value>1</value></property>
+<property><name>job.end.retry.attempts</name><value>0</value></property>
+<property><name>ipc.client.idlethreshold</name><value>4000</value></property>
+<property><name>pregelix.vertexOutputFormatClass</name><value>edu.uci.ics.pregelix.example.EarlyTerminationVertex$SimpleEarlyTerminattionVertexOutputFormat</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>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>mapred.min.split.size</name><value>0</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>ipc.client.tcpnodelay</name><value>false</value></property>
+<property><name>mapred.acls.enabled</name><value>false</value></property>
+</configuration>
\ No newline at end of file
diff --git a/pregelix/pregelix-example/src/test/resources/jobs/MessageOverflow.xml b/pregelix/pregelix-example/src/test/resources/jobs/MessageOverflow.xml
new file mode 100644
index 0000000..8316c64
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/jobs/MessageOverflow.xml
@@ -0,0 +1,144 @@
+<?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:/webmap</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>/result</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>Message Overflow</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>20</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.MessageOverflowVertex</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>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.framesize</name><value>2048</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>${hadoop.tmp.dir}/mapred/system</value></property>
+<property><name>mapred.line.input.format.linespermap</name><value>1</value></property>
+<property><name>job.end.retry.attempts</name><value>0</value></property>
+<property><name>ipc.client.idlethreshold</name><value>4000</value></property>
+<property><name>pregelix.vertexOutputFormatClass</name><value>edu.uci.ics.pregelix.example.MessageOverflowVertex$SimpleMessageOverflowVertexOutputFormat</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>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>pregelix.incStateLength</name><value>true</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>mapred.min.split.size</name><value>0</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>ipc.client.tcpnodelay</name><value>false</value></property>
+<property><name>mapred.acls.enabled</name><value>false</value></property>
+</configuration>
\ No newline at end of file
diff --git a/pregelix/pregelix-example/src/test/resources/jobs/MessageOverflowFixedsize.xml b/pregelix/pregelix-example/src/test/resources/jobs/MessageOverflowFixedsize.xml
new file mode 100644
index 0000000..a894ccd
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/jobs/MessageOverflowFixedsize.xml
@@ -0,0 +1,142 @@
+<?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:/webmap</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>/result</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>Message Overflow Fixedsize</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>20</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.MessageOverflowFixedsizeVertex</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>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.framesize</name><value>2048</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>${hadoop.tmp.dir}/mapred/system</value></property>
+<property><name>mapred.line.input.format.linespermap</name><value>1</value></property>
+<property><name>job.end.retry.attempts</name><value>0</value></property>
+<property><name>ipc.client.idlethreshold</name><value>4000</value></property>
+<property><name>pregelix.vertexOutputFormatClass</name><value>edu.uci.ics.pregelix.example.MessageOverflowFixedsizeVertex$SimpleMessageOverflowVertexOutputFormat</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>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>mapred.min.split.size</name><value>0</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>ipc.client.tcpnodelay</name><value>false</value></property>
+<property><name>mapred.acls.enabled</name><value>false</value></property>
+</configuration>
\ No newline at end of file
diff --git a/pregelix/pregelix-example/src/test/resources/jobs/MessageOverflowLSM.xml b/pregelix/pregelix-example/src/test/resources/jobs/MessageOverflowLSM.xml
new file mode 100644
index 0000000..a9f8925
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/jobs/MessageOverflowLSM.xml
@@ -0,0 +1,145 @@
+<?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:/webmap</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>/result</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>Message Overflow LSM</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>20</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.MessageOverflowVertex</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>pregelix.updateIntensive</name><value>true</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>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.framesize</name><value>2048</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>${hadoop.tmp.dir}/mapred/system</value></property>
+<property><name>mapred.line.input.format.linespermap</name><value>1</value></property>
+<property><name>job.end.retry.attempts</name><value>0</value></property>
+<property><name>ipc.client.idlethreshold</name><value>4000</value></property>
+<property><name>pregelix.vertexOutputFormatClass</name><value>edu.uci.ics.pregelix.example.MessageOverflowVertex$SimpleMessageOverflowVertexOutputFormat</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>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>pregelix.incStateLength</name><value>true</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>mapred.min.split.size</name><value>0</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>ipc.client.tcpnodelay</name><value>false</value></property>
+<property><name>mapred.acls.enabled</name><value>false</value></property>
+</configuration>
\ No newline at end of file
diff --git a/pregelix/pregelix-runtime/pom.xml b/pregelix/pregelix-runtime/pom.xml
index dfba443..6564eb0 100644
--- a/pregelix/pregelix-runtime/pom.xml
+++ b/pregelix/pregelix-runtime/pom.xml
@@ -21,7 +21,7 @@
 	<parent>
     		<groupId>edu.uci.ics.hyracks</groupId>
     		<artifactId>pregelix</artifactId>
-    		<version>0.2.9-SNAPSHOT</version>
+    		<version>0.2.10-SNAPSHOT</version>
   	</parent>
 
 
@@ -88,89 +88,89 @@
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>pregelix-api</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>pregelix-dataflow-std</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>pregelix-dataflow</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-dataflow-std</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<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>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-dataflow-common</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-data-std</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-storage-am-common</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<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>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-storage-am-lsm-common</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-control-cc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-control-nc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
 		<dependency>
 			<groupId>edu.uci.ics.hyracks</groupId>
 			<artifactId>hyracks-ipc</artifactId>
-			<version>0.2.9-SNAPSHOT</version>
+			<version>0.2.10-SNAPSHOT</version>
 			<type>jar</type>
 			<scope>compile</scope>
 		</dependency>
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 16ecf6c..ab564fa 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
@@ -32,8 +32,8 @@
 import edu.uci.ics.hyracks.dataflow.common.comm.io.FrameTupleAppender;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
 import edu.uci.ics.pregelix.api.graph.GlobalAggregator;
+import edu.uci.ics.pregelix.api.graph.MsgList;
 import edu.uci.ics.pregelix.api.graph.Vertex;
-import edu.uci.ics.pregelix.api.util.ArrayListWritable;
 import edu.uci.ics.pregelix.api.util.ArrayListWritable.ArrayIterator;
 import edu.uci.ics.pregelix.api.util.BspUtils;
 import edu.uci.ics.pregelix.api.util.FrameTupleUtils;
@@ -168,11 +168,16 @@
                 tbAlive.reset();
 
                 vertex = (Vertex) tuple[3];
+
+                if (vertex.isPartitionTerminated()) {
+                    vertex.voteToHalt();
+                    return;
+                }
                 vertex.setOutputWriters(writers);
                 vertex.setOutputAppenders(appenders);
                 vertex.setOutputTupleBuilders(tbs);
 
-                ArrayListWritable msgContentList = (ArrayListWritable) tuple[1];
+                MsgList msgContentList = (MsgList) tuple[1];
                 msgContentList.reset(msgIterator);
 
                 if (!msgIterator.hasNext() && vertex.isHalted()) {
@@ -183,9 +188,15 @@
                 }
 
                 try {
+                    if (msgContentList.segmentStart()) {
+                        vertex.open();
+                    }
                     vertex.compute(msgIterator);
+                    if (msgContentList.segmentEnd()) {
+                        vertex.close();
+                    }
                     vertex.finishCompute();
-                } catch (IOException e) {
+                } catch (Exception e) {
                     throw new HyracksDataException(e);
                 }
 
@@ -195,7 +206,10 @@
                 if (terminate && (!vertex.isHalted() || vertex.hasMessage() || vertex.createdNewLiveVertex()))
                     terminate = false;
 
-                aggregator.step(vertex);
+                if (msgContentList.segmentEnd()) {
+                    /** the if condition makes sure aggregate only calls once per-vertex */
+                    aggregator.step(vertex);
+                }
             }
 
             @Override
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 fa7e0a1..b4e1dd8 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
@@ -172,24 +172,26 @@
                 tbAlive.reset();
 
                 vertex = (Vertex) tuple[1];
+                if (vertex.isPartitionTerminated()) {
+                    vertex.voteToHalt();
+                    return;
+                }
                 vertex.setOutputWriters(writers);
                 vertex.setOutputAppenders(appenders);
                 vertex.setOutputTupleBuilders(tbs);
-
-                if (!msgIterator.hasNext() && vertex.isHalted()) {
-                    return;
-                }
+                
                 if (vertex.isHalted()) {
                     vertex.activate();
                 }
 
                 try {
+                    vertex.open();
                     vertex.compute(msgIterator);
+                    vertex.close();
                     vertex.finishCompute();
-                } catch (IOException e) {
+                } catch (Exception e) {
                     throw new HyracksDataException(e);
                 }
-
                 /**
                  * this partition should not terminate
                  */
@@ -200,6 +202,7 @@
                  * call the global aggregator
                  */
                 aggregator.step(vertex);
+
             }
 
             @Override
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 77f28e4..acd766e 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
@@ -14,22 +14,27 @@
  */
 package edu.uci.ics.pregelix.runtime.simpleagg;
 
+import java.nio.ByteBuffer;
+
 import org.apache.commons.lang3.tuple.Pair;
 
 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.data.std.util.ArrayBackedValueStorage;
 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.comm.util.FrameUtils;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.FrameTupleReference;
 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.pregelix.dataflow.group.IClusteredAggregatorDescriptorFactory;
 import edu.uci.ics.pregelix.dataflow.std.base.IAggregateFunction;
 import edu.uci.ics.pregelix.dataflow.std.base.IAggregateFunctionFactory;
 
-public class AccumulatingAggregatorFactory implements IAggregatorDescriptorFactory {
+public class AccumulatingAggregatorFactory implements IClusteredAggregatorDescriptorFactory {
 
     private static final long serialVersionUID = 1L;
     private IAggregateFunctionFactory[] aggFactories;
@@ -41,52 +46,56 @@
     @SuppressWarnings("unchecked")
     @Override
     public IAggregatorDescriptor createAggregator(final IHyracksTaskContext ctx, RecordDescriptor inRecordDesc,
-            RecordDescriptor outRecordDescriptor, int[] aggKeys, int[] partialKeys) throws HyracksDataException {
+            RecordDescriptor outRecordDescriptor, final int[] groupFields, int[] partialgroupFields,
+            final IFrameWriter writer, final ByteBuffer outputFrame, final FrameTupleAppender appender)
+            throws HyracksDataException {
+        final int frameSize = ctx.getFrameSize();
+        final ArrayTupleBuilder internalTupleBuilder = new ArrayTupleBuilder(outRecordDescriptor.getFields().length);
 
         return new IAggregatorDescriptor() {
-
             private FrameTupleReference ftr = new FrameTupleReference();
+            private int groupKeySize = 0;
+            private int metaSlotSize = 4;
+
+            @Override
+            public AggregateState createAggregateStates() {
+                IAggregateFunction[] agg = new IAggregateFunction[aggFactories.length];
+                ArrayBackedValueStorage[] aggOutput = new ArrayBackedValueStorage[aggFactories.length];
+                for (int i = 0; i < agg.length; i++) {
+                    aggOutput[i] = new ArrayBackedValueStorage();
+                    try {
+                        agg[i] = aggFactories[i].createAggregateFunction(ctx, aggOutput[i], writer);
+                    } catch (Exception e) {
+                        throw new IllegalStateException(e);
+                    }
+                }
+                return new AggregateState(Pair.of(aggOutput, agg));
+            }
 
             @Override
             public void init(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
                     AggregateState state) throws HyracksDataException {
-                Pair<ArrayBackedValueStorage[], IAggregateFunction[]> aggState = (Pair<ArrayBackedValueStorage[], IAggregateFunction[]>) state.state;
-                ArrayBackedValueStorage[] aggOutput = aggState.getLeft();
-                IAggregateFunction[] agg = aggState.getRight();
-
-                // initialize aggregate functions
-                for (int i = 0; i < agg.length; i++) {
-                    aggOutput[i].reset();
-                    try {
-                        agg[i].init();
-                    } catch (Exception e) {
-                        throw new HyracksDataException(e);
-                    }
+                setGroupKeySize(accessor, tIndex);
+                initAggregateFunctions(state, true);
+                int stateSize = estimateStep(accessor, tIndex, state);
+                if (stateSize > frameSize) {
+                    throw new HyracksDataException(
+                            "Message combiner intermediate data size "
+                                    + stateSize
+                                    + " is larger than frame size! Check the size estimattion implementation in the message combiner.");
                 }
-
-                ftr.reset(accessor, tIndex);
-                for (int i = 0; i < agg.length; i++) {
-                    try {
-                        agg[i].step(ftr);
-                    } catch (Exception e) {
-                        throw new HyracksDataException(e);
-                    }
-                }
+                singleStep(accessor, tIndex, state);
             }
 
             @Override
             public void aggregate(IFrameTupleAccessor accessor, int tIndex, IFrameTupleAccessor stateAccessor,
                     int stateTupleIndex, AggregateState state) throws HyracksDataException {
-                Pair<ArrayBackedValueStorage[], IAggregateFunction[]> aggState = (Pair<ArrayBackedValueStorage[], IAggregateFunction[]>) state.state;
-                IAggregateFunction[] agg = aggState.getRight();
-                ftr.reset(accessor, tIndex);
-                for (int i = 0; i < agg.length; i++) {
-                    try {
-                        agg[i].step(ftr);
-                    } catch (Exception e) {
-                        throw new HyracksDataException(e);
-                    }
+                int stateSize = estimateStep(accessor, tIndex, state);
+                if (stateSize > frameSize) {
+                    emitResultTuple(accessor, tIndex, state);
+                    initAggregateFunctions(state, false);
                 }
+                singleStep(accessor, tIndex, state);
             }
 
             @Override
@@ -97,7 +106,7 @@
                 IAggregateFunction[] agg = aggState.getRight();
                 for (int i = 0; i < agg.length; i++) {
                     try {
-                        agg[i].finish();
+                        agg[i].finishAll();
                         tupleBuilder.addField(aggOutput[i].getByteArray(), aggOutput[i].getStartOffset(),
                                 aggOutput[i].getLength());
                     } catch (Exception e) {
@@ -107,21 +116,6 @@
             }
 
             @Override
-            public AggregateState createAggregateStates() {
-                IAggregateFunction[] agg = new IAggregateFunction[aggFactories.length];
-                ArrayBackedValueStorage[] aggOutput = new ArrayBackedValueStorage[aggFactories.length];
-                for (int i = 0; i < agg.length; i++) {
-                    aggOutput[i] = new ArrayBackedValueStorage();
-                    try {
-                        agg[i] = aggFactories[i].createAggregateFunction(ctx, aggOutput[i]);
-                    } catch (Exception e) {
-                        throw new IllegalStateException(e);
-                    }
-                }
-                return new AggregateState(Pair.of(aggOutput, agg));
-            }
-
-            @Override
             public void reset() {
 
             }
@@ -137,6 +131,97 @@
 
             }
 
+            private void initAggregateFunctions(AggregateState state, boolean all) throws HyracksDataException {
+                Pair<ArrayBackedValueStorage[], IAggregateFunction[]> aggState = (Pair<ArrayBackedValueStorage[], IAggregateFunction[]>) state.state;
+                ArrayBackedValueStorage[] aggOutput = aggState.getLeft();
+                IAggregateFunction[] agg = aggState.getRight();
+
+                /**
+                 * initialize aggregate functions
+                 */
+                for (int i = 0; i < agg.length; i++) {
+                    aggOutput[i].reset();
+                    try {
+                        if (all) {
+                            agg[i].initAll();
+                        } else {
+                            agg[i].init();
+                        }
+                    } catch (Exception e) {
+                        throw new HyracksDataException(e);
+                    }
+                }
+            }
+
+            private void singleStep(IFrameTupleAccessor accessor, int tIndex, AggregateState state)
+                    throws HyracksDataException {
+                Pair<ArrayBackedValueStorage[], IAggregateFunction[]> aggState = (Pair<ArrayBackedValueStorage[], IAggregateFunction[]>) state.state;
+                IAggregateFunction[] agg = aggState.getRight();
+                ftr.reset(accessor, tIndex);
+                for (int i = 0; i < agg.length; i++) {
+                    try {
+                        agg[i].step(ftr);
+                    } catch (Exception e) {
+                        throw new HyracksDataException(e);
+                    }
+                }
+            }
+
+            private int estimateStep(IFrameTupleAccessor accessor, int tIndex, AggregateState state)
+                    throws HyracksDataException {
+                int size = metaSlotSize + groupKeySize;
+                Pair<ArrayBackedValueStorage[], IAggregateFunction[]> aggState = (Pair<ArrayBackedValueStorage[], IAggregateFunction[]>) state.state;
+                IAggregateFunction[] agg = aggState.getRight();
+                ftr.reset(accessor, tIndex);
+                for (int i = 0; i < agg.length; i++) {
+                    try {
+                        size += agg[i].estimateStep(ftr) + metaSlotSize;
+                    } catch (Exception e) {
+                        throw new HyracksDataException(e);
+                    }
+                }
+                return size * 2;
+            }
+
+            private void emitResultTuple(IFrameTupleAccessor accessor, int tIndex, AggregateState state)
+                    throws HyracksDataException {
+                internalTupleBuilder.reset();
+                for (int j = 0; j < groupFields.length; j++) {
+                    internalTupleBuilder.addField(accessor, tIndex, groupFields[j]);
+                }
+                Pair<ArrayBackedValueStorage[], IAggregateFunction[]> aggState = (Pair<ArrayBackedValueStorage[], IAggregateFunction[]>) state.state;
+                ArrayBackedValueStorage[] aggOutput = aggState.getLeft();
+                IAggregateFunction[] agg = aggState.getRight();
+                for (int i = 0; i < agg.length; i++) {
+                    try {
+                        agg[i].finish();
+                        internalTupleBuilder.addField(aggOutput[i].getByteArray(), aggOutput[i].getStartOffset(),
+                                aggOutput[i].getLength());
+                    } catch (Exception e) {
+                        throw new HyracksDataException(e);
+                    }
+                }
+                if (!appender.appendSkipEmptyField(internalTupleBuilder.getFieldEndOffsets(),
+                        internalTupleBuilder.getByteArray(), 0, internalTupleBuilder.getSize())) {
+                    FrameUtils.flushFrame(outputFrame, writer);
+                    appender.reset(outputFrame, true);
+                    if (!appender.appendSkipEmptyField(internalTupleBuilder.getFieldEndOffsets(),
+                            internalTupleBuilder.getByteArray(), 0, internalTupleBuilder.getSize())) {
+                        throw new HyracksDataException("The output cannot be fit into a frame.");
+                    }
+                }
+            }
+
+            public void setGroupKeySize(IFrameTupleAccessor accessor, int tIndex) {
+                groupKeySize = 0;
+                for (int i = 0; i < groupFields.length; i++) {
+                    int fIndex = groupFields[i];
+                    int fStartOffset = accessor.getFieldStartOffset(tIndex, fIndex);
+                    int fLen = accessor.getFieldEndOffset(tIndex, fIndex) - fStartOffset;
+                    groupKeySize += fLen + metaSlotSize;
+                }
+            }
+
         };
     }
-}
\ No newline at end of file
+}
diff --git a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AggregationFunction.java b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AggregationFunction.java
index 8090dff..5bc30a2 100644
--- a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AggregationFunction.java
+++ b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AggregationFunction.java
@@ -26,6 +26,7 @@
 import org.apache.hadoop.io.WritableComparable;
 
 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.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.dataflow.common.comm.util.ByteBufferInputStream;
@@ -33,6 +34,7 @@
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.IFrameTupleReference;
 import edu.uci.ics.pregelix.api.graph.MessageCombiner;
 import edu.uci.ics.pregelix.api.graph.MsgList;
+import edu.uci.ics.pregelix.api.io.WritableSizable;
 import edu.uci.ics.pregelix.api.util.BspUtils;
 import edu.uci.ics.pregelix.dataflow.base.IConfigurationFactory;
 import edu.uci.ics.pregelix.dataflow.std.base.IAggregateFunction;
@@ -54,10 +56,11 @@
     private MsgList msgList = new MsgList();
     private boolean keyRead = false;
 
-    public AggregationFunction(IHyracksTaskContext ctx, IConfigurationFactory confFactory, DataOutput output,
-            boolean isFinalStage, boolean partialAggAsInput) throws HyracksDataException {
+    public AggregationFunction(IHyracksTaskContext ctx, IConfigurationFactory confFactory, DataOutput tmpOutput,
+            IFrameWriter groupByOutputWriter, boolean isFinalStage, boolean partialAggAsInput)
+            throws HyracksDataException {
         this.conf = confFactory.createConfiguration(ctx);
-        this.output = output;
+        this.output = tmpOutput;
         this.isFinalStage = isFinalStage;
         this.partialAggAsInput = partialAggAsInput;
         msgList.setConf(this.conf);
@@ -68,6 +71,12 @@
     }
 
     @Override
+    public void initAll() throws HyracksDataException {
+        keyRead = false;
+        combiner.initAll(msgList);
+    }
+
+    @Override
     public void init() throws HyracksDataException {
         keyRead = false;
         combiner.init(msgList);
@@ -75,6 +84,43 @@
 
     @Override
     public void step(IFrameTupleReference tuple) throws HyracksDataException {
+        if (!partialAggAsInput) {
+            combiner.stepPartial(key, (WritableSizable) value);
+        } else {
+            combiner.stepFinal(key, value);
+        }
+    }
+
+    @Override
+    public void finish() throws HyracksDataException {
+        try {
+            if (!isFinalStage) {
+                combinedResult = combiner.finishPartial();
+            } else {
+                combinedResult = combiner.finishFinal();
+            }
+            combinedResult.write(output);
+        } catch (IOException e) {
+            throw new HyracksDataException(e);
+        }
+    }
+
+    @Override
+    public void finishAll() throws HyracksDataException {
+        try {
+            if (!isFinalStage) {
+                combinedResult = combiner.finishPartial();
+            } else {
+                combinedResult = combiner.finishFinalAll();
+            }
+            combinedResult.write(output);
+        } catch (IOException e) {
+            throw new HyracksDataException(e);
+        }
+    }
+
+    @Override
+    public int estimateStep(IFrameTupleReference tuple) throws HyracksDataException {
         FrameTupleReference ftr = (FrameTupleReference) tuple;
         IFrameTupleAccessor fta = ftr.getFrameTupleAccessor();
         ByteBuffer buffer = fta.getBuffer();
@@ -94,28 +140,13 @@
             }
             value.readFields(valueInput);
             if (!partialAggAsInput) {
-                combiner.stepPartial(key, value);
+                return combiner.estimateAccumulatedStateByteSizePartial(key, (WritableSizable) value);
             } else {
-                combiner.stepFinal(key, value);
+                return combiner.estimateAccumulatedStateByteSizeFinal(key, value);
             }
         } catch (IOException e) {
             throw new HyracksDataException(e);
         }
-
-    }
-
-    @Override
-    public void finish() throws HyracksDataException {
-        try {
-            if (!isFinalStage) {
-                combinedResult = combiner.finishPartial();
-            } else {
-                combinedResult = combiner.finishFinal();
-            }
-            combinedResult.write(output);
-        } catch (IOException e) {
-            throw new HyracksDataException(e);
-        }
     }
 
 }
diff --git a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AggregationFunctionFactory.java b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AggregationFunctionFactory.java
index 33dfa5d..54eccf5 100644
--- a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AggregationFunctionFactory.java
+++ b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AggregationFunctionFactory.java
@@ -17,6 +17,7 @@
 
 import java.io.DataOutput;
 
+import edu.uci.ics.hyracks.api.comm.IFrameWriter;
 import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
 import edu.uci.ics.hyracks.api.exceptions.HyracksException;
 import edu.uci.ics.hyracks.data.std.api.IDataOutputProvider;
@@ -37,9 +38,9 @@
     }
 
     @Override
-    public IAggregateFunction createAggregateFunction(IHyracksTaskContext ctx, IDataOutputProvider provider)
-            throws HyracksException {
+    public IAggregateFunction createAggregateFunction(IHyracksTaskContext ctx, IDataOutputProvider provider,
+            IFrameWriter writer) throws HyracksException {
         DataOutput output = provider.getDataOutput();
-        return new AggregationFunction(ctx, confFactory, output, isFinalStage, partialAggAsInput);
+        return new AggregationFunction(ctx, confFactory, output, writer, isFinalStage, partialAggAsInput);
     }
 }
diff --git a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/MsgListNullWriterFactory.java b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/MsgListNullWriterFactory.java
index 4eaa21c..b7689de 100644
--- a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/MsgListNullWriterFactory.java
+++ b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/MsgListNullWriterFactory.java
@@ -32,6 +32,7 @@
             @Override
             public void writeNull(DataOutput out) throws HyracksDataException {
                 try {
+                    out.writeByte(3); //start|end
                     out.writeInt(0);
                 } catch (IOException e) {
                     throw new HyracksDataException(e);
diff --git a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/PreSuperStepRuntimeHookFactory.java b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/PreSuperStepRuntimeHookFactory.java
index 99bcac5..cd2012a 100644
--- a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/PreSuperStepRuntimeHookFactory.java
+++ b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/touchpoint/PreSuperStepRuntimeHookFactory.java
@@ -26,11 +26,11 @@
 public class PreSuperStepRuntimeHookFactory implements IRuntimeHookFactory {
     private static final long serialVersionUID = 1L;
     private final IConfigurationFactory confFactory;
-    private final String giraphJobId;
+    private final String jobId;
 
-    public PreSuperStepRuntimeHookFactory(String giraphJobId, IConfigurationFactory confFactory) {
+    public PreSuperStepRuntimeHookFactory(String jobId, IConfigurationFactory confFactory) {
         this.confFactory = confFactory;
-        this.giraphJobId = giraphJobId;
+        this.jobId = jobId;
     }
 
     @Override
@@ -40,7 +40,7 @@
             @Override
             public void configure(IHyracksTaskContext ctx) throws HyracksDataException {
                 Configuration conf = confFactory.createConfiguration(ctx);
-                IterationUtils.setProperties(giraphJobId, ctx, conf);
+                IterationUtils.setProperties(jobId, ctx, conf);
             }
 
         };