diff --git a/hyracks/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/am/lsm/btree/LSMBTreeOperatorTestHelper.java b/hyracks/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/am/lsm/btree/LSMBTreeOperatorTestHelper.java
index a4fd4c1..f4d422b 100644
--- a/hyracks/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/am/lsm/btree/LSMBTreeOperatorTestHelper.java
+++ b/hyracks/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/am/lsm/btree/LSMBTreeOperatorTestHelper.java
@@ -43,7 +43,7 @@
         return new LSMBTreeDataflowHelperFactory(virtualBufferCacheProvider, new ConstantMergePolicyFactory(),
                 MERGE_POLICY_PROPERTIES, ThreadCountingOperationTrackerProvider.INSTANCE,
                 SynchronousSchedulerProvider.INSTANCE, NoOpIOOperationCallback.INSTANCE,
-                DEFAULT_BLOOM_FILTER_FALSE_POSITIVE_RATE);
+                DEFAULT_BLOOM_FILTER_FALSE_POSITIVE_RATE, true);
     }
 
 }
diff --git a/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/dataflow/LSMBTreeDataflowHelper.java b/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/dataflow/LSMBTreeDataflowHelper.java
index 8a3c313..2708a81 100644
--- a/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/dataflow/LSMBTreeDataflowHelper.java
+++ b/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/dataflow/LSMBTreeDataflowHelper.java
@@ -31,21 +31,24 @@
 import edu.uci.ics.hyracks.storage.am.lsm.common.dataflow.AbstractLSMIndexDataflowHelper;
 
 public class LSMBTreeDataflowHelper extends AbstractLSMIndexDataflowHelper {
+    
+    private final boolean needKeyDupCheck;
 
     public LSMBTreeDataflowHelper(IIndexOperatorDescriptor opDesc, IHyracksTaskContext ctx, int partition,
             List<IVirtualBufferCache> virtualBufferCaches, ILSMMergePolicy mergePolicy,
             ILSMOperationTrackerProvider opTrackerFactory, ILSMIOOperationScheduler ioScheduler,
-            ILSMIOOperationCallbackFactory ioOpCallbackFactory) {
+            ILSMIOOperationCallbackFactory ioOpCallbackFactory, boolean needKeyDupCheck) {
         this(opDesc, ctx, partition, virtualBufferCaches, DEFAULT_BLOOM_FILTER_FALSE_POSITIVE_RATE, mergePolicy,
-                opTrackerFactory, ioScheduler, ioOpCallbackFactory);
+                opTrackerFactory, ioScheduler, ioOpCallbackFactory, needKeyDupCheck);
     }
 
     public LSMBTreeDataflowHelper(IIndexOperatorDescriptor opDesc, IHyracksTaskContext ctx, int partition,
             List<IVirtualBufferCache> virtualBufferCaches, double bloomFilterFalsePositiveRate,
             ILSMMergePolicy mergePolicy, ILSMOperationTrackerProvider opTrackerFactory,
-            ILSMIOOperationScheduler ioScheduler, ILSMIOOperationCallbackFactory ioOpCallbackFactory) {
+            ILSMIOOperationScheduler ioScheduler, ILSMIOOperationCallbackFactory ioOpCallbackFactory, boolean needKeyDupCheck) {
         super(opDesc, ctx, partition, virtualBufferCaches, bloomFilterFalsePositiveRate, mergePolicy, opTrackerFactory,
                 ioScheduler, ioOpCallbackFactory);
+        this.needKeyDupCheck = needKeyDupCheck;
     }
 
     @Override
@@ -55,6 +58,6 @@
                 opDesc.getStorageManager().getFileMapProvider(ctx), treeOpDesc.getTreeIndexTypeTraits(),
                 treeOpDesc.getTreeIndexComparatorFactories(), treeOpDesc.getTreeIndexBloomFilterKeyFields(),
                 bloomFilterFalsePositiveRate, mergePolicy, opTrackerFactory.getOperationTracker(ctx), ioScheduler,
-                ioOpCallbackFactory.createIOOperationCallback());
+                ioOpCallbackFactory.createIOOperationCallback(), needKeyDupCheck);
     }
 }
diff --git a/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/dataflow/LSMBTreeDataflowHelperFactory.java b/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/dataflow/LSMBTreeDataflowHelperFactory.java
index 0fdef13..7fe7702 100644
--- a/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/dataflow/LSMBTreeDataflowHelperFactory.java
+++ b/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/dataflow/LSMBTreeDataflowHelperFactory.java
@@ -30,13 +30,17 @@
 public class LSMBTreeDataflowHelperFactory extends AbstractLSMIndexDataflowHelperFactory {
 
     private static final long serialVersionUID = 1L;
+    private final boolean needKeyDupCheck;
 
     public LSMBTreeDataflowHelperFactory(IVirtualBufferCacheProvider virtualBufferCacheProvider,
             ILSMMergePolicyFactory mergePolicyFactory, Map<String, String> mergePolicyProperties,
             ILSMOperationTrackerProvider opTrackerFactory, ILSMIOOperationSchedulerProvider ioSchedulerProvider,
-            ILSMIOOperationCallbackFactory ioOpCallbackFactory, double bloomFilterFalsePositiveRate) {
+            ILSMIOOperationCallbackFactory ioOpCallbackFactory, double bloomFilterFalsePositiveRate,
+            boolean needKeyDupCheck) {
         super(virtualBufferCacheProvider, mergePolicyFactory, mergePolicyProperties, opTrackerFactory,
                 ioSchedulerProvider, ioOpCallbackFactory, bloomFilterFalsePositiveRate);
+        this.needKeyDupCheck = needKeyDupCheck;
+
     }
 
     @Override
@@ -45,6 +49,6 @@
         return new LSMBTreeDataflowHelper(opDesc, ctx, partition,
                 virtualBufferCacheProvider.getVirtualBufferCaches(ctx), bloomFilterFalsePositiveRate,
                 mergePolicyFactory.createMergePolicy(mergePolicyProperties), opTrackerFactory,
-                ioSchedulerProvider.getIOScheduler(ctx), ioOpCallbackFactory);
+                ioSchedulerProvider.getIOScheduler(ctx), ioOpCallbackFactory, needKeyDupCheck);
     }
 }
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 cb4d268..19307e9 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
@@ -85,13 +85,15 @@
     private final ITreeIndexFrameFactory deleteLeafFrameFactory;
     private final IBinaryComparatorFactory[] cmpFactories;
 
+    private final boolean needKeyDupCheck;
+
     public LSMBTree(List<IVirtualBufferCache> virtualBufferCaches, ITreeIndexFrameFactory interiorFrameFactory,
             ITreeIndexFrameFactory insertLeafFrameFactory, ITreeIndexFrameFactory deleteLeafFrameFactory,
             ILSMIndexFileManager fileManager, TreeIndexFactory<BTree> diskBTreeFactory,
             TreeIndexFactory<BTree> bulkLoadBTreeFactory, BloomFilterFactory bloomFilterFactory,
             double bloomFilterFalsePositiveRate, IFileMapProvider diskFileMapProvider, int fieldCount,
             IBinaryComparatorFactory[] cmpFactories, ILSMMergePolicy mergePolicy, ILSMOperationTracker opTracker,
-            ILSMIOOperationScheduler ioScheduler, ILSMIOOperationCallback ioOpCallback) {
+            ILSMIOOperationScheduler ioScheduler, ILSMIOOperationCallback ioOpCallback, boolean needKeyDupCheck) {
         super(virtualBufferCaches, diskBTreeFactory.getBufferCache(), fileManager, diskFileMapProvider,
                 bloomFilterFalsePositiveRate, mergePolicy, opTracker, ioScheduler, ioOpCallback);
         int i = 0;
@@ -110,6 +112,7 @@
         this.cmpFactories = cmpFactories;
         componentFactory = new LSMBTreeDiskComponentFactory(diskBTreeFactory, bloomFilterFactory);
         bulkLoadComponentFactory = new LSMBTreeDiskComponentFactory(bulkLoadBTreeFactory, bloomFilterFactory);
+        this.needKeyDupCheck = needKeyDupCheck;
     }
 
     @Override
@@ -303,43 +306,45 @@
         IIndexCursor memCursor = new BTreeRangeSearchCursor(ctx.currentMutableBTreeOpCtx.leafFrame, false);
         RangePredicate predicate = new RangePredicate(tuple, tuple, true, true, comparator, comparator);
 
-        // first check the inmemory component
-        ctx.currentMutableBTreeAccessor.search(memCursor, predicate);
-        try {
-            if (memCursor.hasNext()) {
-                memCursor.next();
-                LSMBTreeTupleReference lsmbtreeTuple = (LSMBTreeTupleReference) memCursor.getTuple();
-                if (!lsmbtreeTuple.isAntimatter()) {
-                    throw new TreeIndexDuplicateKeyException("Failed to insert key since key already exists.");
-                } else {
-                    memCursor.close();
-                    ctx.currentMutableBTreeAccessor.upsertIfConditionElseInsert(tuple,
-                            AntimatterAwareTupleAcceptor.INSTANCE);
-                    return true;
+        if (needKeyDupCheck) {
+            // first check the inmemory component
+            ctx.currentMutableBTreeAccessor.search(memCursor, predicate);
+            try {
+                if (memCursor.hasNext()) {
+                    memCursor.next();
+                    LSMBTreeTupleReference lsmbtreeTuple = (LSMBTreeTupleReference) memCursor.getTuple();
+                    if (!lsmbtreeTuple.isAntimatter()) {
+                        throw new TreeIndexDuplicateKeyException("Failed to insert key since key already exists.");
+                    } else {
+                        memCursor.close();
+                        ctx.currentMutableBTreeAccessor.upsertIfConditionElseInsert(tuple,
+                                AntimatterAwareTupleAcceptor.INSTANCE);
+                        return true;
+                    }
                 }
+            } finally {
+                memCursor.close();
             }
-        } finally {
-            memCursor.close();
-        }
 
-        // TODO: Can we just remove the above code that search the mutable
-        // component and do it together with the search call below? i.e. instead
-        // of passing false to the lsmHarness.search(), we pass true to include
-        // the mutable component?
-        // the key was not in the inmemory component, so check the disk
-        // components
+            // TODO: Can we just remove the above code that search the mutable
+            // component and do it together with the search call below? i.e. instead
+            // of passing false to the lsmHarness.search(), we pass true to include
+            // the mutable component?
+            // the key was not in the inmemory component, so check the disk
+            // components
 
-        // This is a hack to avoid searching the current active mutable component twice. It is critical to add it back once the search is over.
-        ILSMComponent firstComponent = ctx.getComponentHolder().remove(0);
-        search(ctx, searchCursor, predicate);
-        try {
-            if (searchCursor.hasNext()) {
-                throw new TreeIndexDuplicateKeyException("Failed to insert key since key already exists.");
+            // This is a hack to avoid searching the current active mutable component twice. It is critical to add it back once the search is over.
+            ILSMComponent firstComponent = ctx.getComponentHolder().remove(0);
+            search(ctx, searchCursor, predicate);
+            try {
+                if (searchCursor.hasNext()) {
+                    throw new TreeIndexDuplicateKeyException("Failed to insert key since key already exists.");
+                }
+            } finally {
+                searchCursor.close();
+                // Add the current active mutable component back
+                ctx.getComponentHolder().add(0, firstComponent);
             }
-        } finally {
-            searchCursor.close();
-            // Add the current active mutable component back
-            ctx.getComponentHolder().add(0, firstComponent);
         }
 
         ctx.currentMutableBTreeAccessor.upsertIfConditionElseInsert(tuple, AntimatterAwareTupleAcceptor.INSTANCE);
diff --git a/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeUtils.java b/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeUtils.java
index 8b363ff..88148c3 100644
--- a/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeUtils.java
+++ b/hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeUtils.java
@@ -49,7 +49,7 @@
             IBufferCache diskBufferCache, IFileMapProvider diskFileMapProvider, ITypeTraits[] typeTraits,
             IBinaryComparatorFactory[] cmpFactories, int[] bloomFilterKeyFields, double bloomFilterFalsePositiveRate,
             ILSMMergePolicy mergePolicy, ILSMOperationTracker opTracker, ILSMIOOperationScheduler ioScheduler,
-            ILSMIOOperationCallback ioOpCallback) {
+            ILSMIOOperationCallback ioOpCallback, boolean needKeyDupCheck) {
         LSMBTreeTupleWriterFactory insertTupleWriterFactory = new LSMBTreeTupleWriterFactory(typeTraits,
                 cmpFactories.length, false);
         LSMBTreeTupleWriterFactory deleteTupleWriterFactory = new LSMBTreeTupleWriterFactory(typeTraits,
@@ -78,7 +78,7 @@
         LSMBTree lsmTree = new LSMBTree(virtualBufferCaches, interiorFrameFactory, insertLeafFrameFactory,
                 deleteLeafFrameFactory, fileNameManager, diskBTreeFactory, bulkLoadBTreeFactory, bloomFilterFactory,
                 bloomFilterFalsePositiveRate, diskFileMapProvider, typeTraits.length, cmpFactories, mergePolicy,
-                opTracker, ioScheduler, ioOpCallback);
+                opTracker, ioScheduler, ioOpCallback, needKeyDupCheck);
         return lsmTree;
     }
 }
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeExamplesTest.java b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeExamplesTest.java
index dc55f5d..f174ce4 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeExamplesTest.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeExamplesTest.java
@@ -37,7 +37,7 @@
         return LSMBTreeUtils.createLSMTree(harness.getVirtualBufferCaches(), harness.getFileReference(),
                 harness.getDiskBufferCache(), harness.getDiskFileMapProvider(), typeTraits, cmpFactories,
                 bloomFilterKeyFields, harness.getBoomFilterFalsePositiveRate(), harness.getMergePolicy(),
-                harness.getOperationTracker(), harness.getIOScheduler(), harness.getIOOperationCallback());
+                harness.getOperationTracker(), harness.getIOScheduler(), harness.getIOOperationCallback(), true);
     }
 
     @Before
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeModificationOperationCallbackTest.java b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeModificationOperationCallbackTest.java
index 2234075..9881975 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeModificationOperationCallbackTest.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeModificationOperationCallbackTest.java
@@ -48,7 +48,7 @@
                 SerdeUtils.serdesToComparatorFactories(keySerdes, keySerdes.length), bloomFilterKeyFields,
                 harness.getBoomFilterFalsePositiveRate(), harness.getMergePolicy(),
                 NoOpOperationTrackerProvider.INSTANCE.getOperationTracker(null), harness.getIOScheduler(),
-                harness.getIOOperationCallback());
+                harness.getIOOperationCallback(), true);
     }
 
     @Override
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeSearchOperationCallbackTest.java b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeSearchOperationCallbackTest.java
index afaf30b..d4a0857 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeSearchOperationCallbackTest.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeSearchOperationCallbackTest.java
@@ -55,7 +55,7 @@
                 SerdeUtils.serdesToComparatorFactories(keySerdes, keySerdes.length), bloomFilterKeyFields,
                 harness.getBoomFilterFalsePositiveRate(), harness.getMergePolicy(),
                 NoOpOperationTrackerProvider.INSTANCE.getOperationTracker(null), harness.getIOScheduler(),
-                harness.getIOOperationCallback());
+                harness.getIOOperationCallback(), true);
     }
 
     @Override
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeMultiThreadTest.java b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeMultiThreadTest.java
index adee618..c6f0a65 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeMultiThreadTest.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeMultiThreadTest.java
@@ -53,7 +53,7 @@
         return LSMBTreeUtils.createLSMTree(harness.getVirtualBufferCaches(), harness.getFileReference(),
                 harness.getDiskBufferCache(), harness.getDiskFileMapProvider(), typeTraits, cmpFactories,
                 bloomFilterKeyFields, harness.getBoomFilterFalsePositiveRate(), harness.getMergePolicy(),
-                harness.getOperationTracker(), harness.getIOScheduler(), harness.getIOOperationCallback());
+                harness.getOperationTracker(), harness.getIOScheduler(), harness.getIOOperationCallback(), true);
     }
 
     @Override
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/LSMTreeRunner.java b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/LSMTreeRunner.java
index fb06a7e..045aed0 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/LSMTreeRunner.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/LSMTreeRunner.java
@@ -109,7 +109,7 @@
 
         lsmtree = LSMBTreeUtils.createLSMTree(virtualBufferCaches, file, bufferCache, fmp, typeTraits, cmpFactories,
                 bloomFilterKeyFields, bloomFilterFalsePositiveRate, NoMergePolicy.INSTANCE,
-                new ThreadCountingTracker(), ioScheduler, NoOpIOOperationCallback.INSTANCE);
+                new ThreadCountingTracker(), ioScheduler, NoOpIOOperationCallback.INSTANCE, true);
     }
 
     @Override
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeTestContext.java b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeTestContext.java
index 6f7c23a..84ea6df 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeTestContext.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeTestContext.java
@@ -76,7 +76,7 @@
         }
         LSMBTree lsmTree = LSMBTreeUtils.createLSMTree(virtualBufferCaches, file, diskBufferCache, diskFileMapProvider,
                 typeTraits, cmpFactories, bloomFilterKeyFields, bloomFilterFalsePositiveRate, mergePolicy, opTracker,
-                ioScheduler, ioOpCallback);
+                ioScheduler, ioOpCallback, true);
         LSMBTreeTestContext testCtx = new LSMBTreeTestContext(fieldSerdes, lsmTree);
         return testCtx;
     }
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 163e476..64c4ea3 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
@@ -507,7 +507,8 @@
         if (BspUtils.useLSM(conf)) {
             return new LSMBTreeDataflowHelperFactory(new VirtualBufferCacheProvider(),
                     new ConstantMergePolicyFactory(), MERGE_POLICY_PROPERTIES, NoOpOperationTrackerProvider.INSTANCE,
-                    SynchronousSchedulerProvider.INSTANCE, NoOpIOOperationCallback.INSTANCE, 0.01);
+                    /* TODO verify whether key dup check is required or not in preglix: to be safe, just check it as it has been done*/
+                    SynchronousSchedulerProvider.INSTANCE, NoOpIOOperationCallback.INSTANCE, 0.01, true);
         } else {
             return new BTreeDataflowHelperFactory();
         }
@@ -889,7 +890,7 @@
     public void setLocationConstraint(JobSpecification spec, IOperatorDescriptor operator) {
         optimizer.setOptimizedLocationConstraints(spec, operator);
     }
-    
+
     /**
      * get the file split provider
      * 
@@ -897,7 +898,7 @@
      * @param indexName
      * @return the IFileSplitProvider instance
      */
-    public IFileSplitProvider getFileSplitProvider(String jobId, String indexName){
+    public IFileSplitProvider getFileSplitProvider(String jobId, String indexName) {
         return optimizer.getOptimizedFileSplitProvider(jobId, indexName);
     }