diff --git a/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGen.java b/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGen.java
index 88edc91..b345e01 100644
--- a/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGen.java
+++ b/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/JobGen.java
@@ -25,7 +25,9 @@
 import java.io.IOException;
 import java.lang.reflect.Type;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.UUID;
 import java.util.logging.Logger;
 
@@ -75,7 +77,7 @@
 import edu.uci.ics.hyracks.storage.am.common.dataflow.TreeIndexCreateOperatorDescriptor;
 import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallbackFactory;
 import edu.uci.ics.hyracks.storage.am.lsm.btree.dataflow.LSMBTreeDataflowHelperFactory;
-import edu.uci.ics.hyracks.storage.am.lsm.common.impls.ConstantMergePolicyProvider;
+import edu.uci.ics.hyracks.storage.am.lsm.common.impls.ConstantMergePolicyFactory;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.NoOpIOOperationCallback;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.NoOpOperationTrackerProvider;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.SynchronousSchedulerProvider;
@@ -136,6 +138,12 @@
     protected int frameSize = ClusterConfig.getFrameSize();
     protected int maxFrameNumber = (int) (((long) 32 * MB) / frameSize);
 
+    private static final Map<String, String> MERGE_POLICY_PROPERTIES;
+    static {
+        MERGE_POLICY_PROPERTIES = new HashMap<String, String>();
+        MERGE_POLICY_PROPERTIES.put("num-components", "3");
+    }
+
     protected static final String SECONDARY_INDEX_ODD = "secondary1";
     protected static final String SECONDARY_INDEX_EVEN = "secondary2";
 
@@ -478,9 +486,9 @@
 
     protected IIndexDataflowHelperFactory getIndexDataflowHelperFactory() {
         if (BspUtils.useLSM(conf)) {
-            return new LSMBTreeDataflowHelperFactory(new VirtualBufferCacheProvider(), new ConstantMergePolicyProvider(
-                    3), NoOpOperationTrackerProvider.INSTANCE, SynchronousSchedulerProvider.INSTANCE,
-                    NoOpIOOperationCallback.INSTANCE, 0.01);
+            return new LSMBTreeDataflowHelperFactory(new VirtualBufferCacheProvider(),
+                    new ConstantMergePolicyFactory(), MERGE_POLICY_PROPERTIES, NoOpOperationTrackerProvider.INSTANCE,
+                    SynchronousSchedulerProvider.INSTANCE, NoOpIOOperationCallback.INSTANCE, 0.01);
         } else {
             return new BTreeDataflowHelperFactory();
         }
diff --git a/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AccumulatingAggregatorFactory.java b/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AccumulatingAggregatorFactory.java
index acd766e..d243c8a 100644
--- a/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AccumulatingAggregatorFactory.java
+++ b/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AccumulatingAggregatorFactory.java
@@ -99,7 +99,7 @@
             }
 
             @Override
-            public void outputFinalResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
+            public boolean outputFinalResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
                     AggregateState state) throws HyracksDataException {
                 Pair<ArrayBackedValueStorage[], IAggregateFunction[]> aggState = (Pair<ArrayBackedValueStorage[], IAggregateFunction[]>) state.state;
                 ArrayBackedValueStorage[] aggOutput = aggState.getLeft();
@@ -113,6 +113,7 @@
                         throw new HyracksDataException(e);
                     }
                 }
+                return true;
             }
 
             @Override
@@ -121,7 +122,7 @@
             }
 
             @Override
-            public void outputPartialResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
+            public boolean outputPartialResult(ArrayTupleBuilder tupleBuilder, IFrameTupleAccessor accessor, int tIndex,
                     AggregateState state) throws HyracksDataException {
                 throw new IllegalStateException("this method should not be called");
             }