diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenThread.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenThread.java
index ff29b33..6fff620 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenThread.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenThread.java
@@ -38,7 +38,8 @@
     private TupleBatch[] tupleBatches;
     private int ringPos;
     
-    public DataGenThread(int numConsumers, int maxNumBatches, int batchSize, ISerializerDeserializer[] fieldSerdes, int payloadSize, int rndSeed, int maxOutstandingBatches, boolean sorted) {
+    public DataGenThread(int numConsumers, int maxNumBatches, int batchSize, ISerializerDeserializer[] fieldSerdes,
+            int payloadSize, int rndSeed, int maxOutstandingBatches, boolean sorted) {
         this.maxNumBatches = maxNumBatches;
         this.maxOutstandingBatches = maxOutstandingBatches;
         rnd = new Random(rndSeed);
diff --git a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMTreeSearchCursor.java b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMTreeSearchCursor.java
index cad4a4a..e95bf86 100644
--- a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMTreeSearchCursor.java
+++ b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMTreeSearchCursor.java
@@ -89,9 +89,6 @@
     public void next() throws HyracksDataException {
         outputElement = outputPriorityQueue.poll();
         needPush = true;
-        if (outputElement == null) {
-            throw new HyracksDataException("The outputPriorityQueue is empty");
-        }
     }
 
     @Override
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/api/IInvertedListBuilderFactory.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/api/IInvertedListBuilderFactory.java
new file mode 100644
index 0000000..9cde18b
--- /dev/null
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/api/IInvertedListBuilderFactory.java
@@ -0,0 +1,20 @@
+/*
+ * Copyright 2009-2012 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api;
+
+public interface IInvertedListBuilderFactory {
+    public IInvertedListBuilder create();
+}
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndex.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndex.java
index 2689294..f6a7002 100644
--- a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndex.java
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndex.java
@@ -299,42 +299,6 @@
     }
     
     @Override
-    public ILSMIOOperation createMergeOperation(ILSMIOOperationCallback callback) throws HyracksDataException,
-            IndexException {
-        LSMInvertedIndexOpContext ctx = createOpContext();
-        ctx.reset(IndexOp.SEARCH);
-        IIndexCursor cursor = new LSMInvertedIndexRangeSearchCursor();
-        RangePredicate mergePred = new RangePredicate(null, null, true, true, null, null);
-
-        // Scan diskInvertedIndexes ignoring the memoryInvertedIndex.
-        List<Object> mergingComponents = lsmHarness.search(cursor, mergePred, ctx, false);
-        if (mergingComponents.size() <= 1) {
-            cursor.close();
-            return null;
-        }
-
-        LSMInvertedIndexComponent firstComponent = (LSMInvertedIndexComponent) mergingComponents.get(0);
-        OnDiskInvertedIndex firstInvIndex = (OnDiskInvertedIndex) firstComponent.getInvIndex();
-        String firstFileName = firstInvIndex.getBTree().getFileReference().getFile().getName();
-
-        LSMInvertedIndexComponent lastComponent = (LSMInvertedIndexComponent) mergingComponents.get(mergingComponents
-                .size() - 1);
-        OnDiskInvertedIndex lastInvIndex = (OnDiskInvertedIndex) lastComponent.getInvIndex();
-        String lastFileName = lastInvIndex.getBTree().getFileReference().getFile().getName();
-
-        LSMInvertedIndexFileNameComponent fileNameComponent = (LSMInvertedIndexFileNameComponent) fileManager
-                .getRelMergeFileName(firstFileName, lastFileName);
-        FileReference dictBTreeFileRef = fileManager.createMergeFile(fileNameComponent.getDictBTreeFileName());
-        FileReference deletedKeysBTreeFileRef = fileManager.createMergeFile(fileNameComponent
-                .getDeletedKeysBTreeFileName());
-
-        LSMInvertedIndexMergeOperation mergeOp = new LSMInvertedIndexMergeOperation(this, mergingComponents, cursor,
-                dictBTreeFileRef, deletedKeysBTreeFileRef, callback);
-
-        return mergeOp;
-    }
-    
-    @Override
     public IIndexBulkLoader createBulkLoader(float fillFactor, boolean verifyInput) throws IndexException {
         return new LSMInvertedIndexBulkLoader(fillFactor, verifyInput);
     }
@@ -457,7 +421,6 @@
         IInvertedIndex mergedDiskInvertedIndex = createDiskInvIndex(diskInvIndexFactory,
                 mergeOp.getDictBTreeMergeTarget(), true);
         IIndexCursor cursor = mergeOp.getCursor();
-        // TODO: Reset verifyInput to false.
         IIndexBulkLoader invIndexBulkLoader = mergedDiskInvertedIndex.createBulkLoader(1.0f, true);
         try {
             while (cursor.hasNext()) {
@@ -481,6 +444,42 @@
     }
     
     @Override
+    public ILSMIOOperation createMergeOperation(ILSMIOOperationCallback callback) throws HyracksDataException,
+            IndexException {
+        LSMInvertedIndexOpContext ctx = createOpContext();
+        ctx.reset(IndexOp.SEARCH);
+        IIndexCursor cursor = new LSMInvertedIndexRangeSearchCursor();
+        RangePredicate mergePred = new RangePredicate(null, null, true, true, null, null);
+
+        // Scan diskInvertedIndexes ignoring the memoryInvertedIndex.
+        List<Object> mergingComponents = lsmHarness.search(cursor, mergePred, ctx, false);
+        if (mergingComponents.size() <= 1) {
+            cursor.close();
+            return null;
+        }
+
+        LSMInvertedIndexComponent firstComponent = (LSMInvertedIndexComponent) mergingComponents.get(0);
+        OnDiskInvertedIndex firstInvIndex = (OnDiskInvertedIndex) firstComponent.getInvIndex();
+        String firstFileName = firstInvIndex.getBTree().getFileReference().getFile().getName();
+
+        LSMInvertedIndexComponent lastComponent = (LSMInvertedIndexComponent) mergingComponents.get(mergingComponents
+                .size() - 1);
+        OnDiskInvertedIndex lastInvIndex = (OnDiskInvertedIndex) lastComponent.getInvIndex();
+        String lastFileName = lastInvIndex.getBTree().getFileReference().getFile().getName();
+
+        LSMInvertedIndexFileNameComponent fileNameComponent = (LSMInvertedIndexFileNameComponent) fileManager
+                .getRelMergeFileName(firstFileName, lastFileName);
+        FileReference dictBTreeFileRef = fileManager.createMergeFile(fileNameComponent.getDictBTreeFileName());
+        FileReference deletedKeysBTreeFileRef = fileManager.createMergeFile(fileNameComponent
+                .getDeletedKeysBTreeFileName());
+
+        LSMInvertedIndexMergeOperation mergeOp = new LSMInvertedIndexMergeOperation(this, mergingComponents, cursor,
+                dictBTreeFileRef, deletedKeysBTreeFileRef, callback);
+
+        return mergeOp;
+    }
+    
+    @Override
     public void addMergedComponent(Object newComponent, List<Object> mergedComponents) {
         diskComponents.removeAll(mergedComponents);
         diskComponents.addLast(newComponent);
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/FixedSizeElementInvertedListCursor.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/FixedSizeElementInvertedListCursor.java
index d32c3c4..ed8f600 100644
--- a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/FixedSizeElementInvertedListCursor.java
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/FixedSizeElementInvertedListCursor.java
@@ -78,7 +78,6 @@
         } else {
             currentOff += elementSize;
         }
-
         currentElementIx++;
         tuple.reset(pages[currentPageIx].getBuffer().array(), currentOff);
     }
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndex.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndex.java
index 2740970..8e15526 100644
--- a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndex.java
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndex.java
@@ -393,7 +393,6 @@
 
             if (verifyInput && lastTupleBuilder.getSize() != 0) {
                 if (allCmp.compare(tuple, lastTuple) <= 0) {
-                    System.out.println("FOUND YOU!");
                     throw new UnsortedInputException(
                             "Input stream given to OnDiskInvertedIndex bulk load is not sorted.");
                 }
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexFactory.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexFactory.java
index b044ebe..5401519 100644
--- a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexFactory.java
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexFactory.java
@@ -22,14 +22,15 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.IndexFactory;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedIndex;
-import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedListBuilder;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedIndexFileNameMapper;
+import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedListBuilder;
+import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedListBuilderFactory;
 import edu.uci.ics.hyracks.storage.common.buffercache.IBufferCache;
 import edu.uci.ics.hyracks.storage.common.file.IFileMapProvider;
 
 public class OnDiskInvertedIndexFactory extends IndexFactory<IInvertedIndex> {
 
-    protected final IInvertedListBuilder invListBuilder;
+    protected final IInvertedListBuilderFactory invListBuilderFactory;
     protected final ITypeTraits[] invListTypeTraits;
     protected final IBinaryComparatorFactory[] invListCmpFactories;
     protected final ITypeTraits[] tokenTypeTraits;
@@ -37,11 +38,11 @@
     protected final IInvertedIndexFileNameMapper fileNameMapper;
 
     public OnDiskInvertedIndexFactory(IBufferCache bufferCache, IFileMapProvider fileMapProvider,
-            IInvertedListBuilder invListBuilder, ITypeTraits[] invListTypeTraits,
+            IInvertedListBuilderFactory invListBuilderFactory, ITypeTraits[] invListTypeTraits,
             IBinaryComparatorFactory[] invListCmpFactories, ITypeTraits[] tokenTypeTraits,
             IBinaryComparatorFactory[] tokenCmpFactories, IInvertedIndexFileNameMapper fileNameMapper) {
         super(bufferCache, fileMapProvider, null);
-        this.invListBuilder = invListBuilder;
+        this.invListBuilderFactory = invListBuilderFactory;
         this.invListTypeTraits = invListTypeTraits;
         this.invListCmpFactories = invListCmpFactories;
         this.tokenTypeTraits = tokenTypeTraits;
@@ -53,6 +54,7 @@
     public IInvertedIndex createIndexInstance(FileReference dictBTreeFile) throws IndexException {
         String invListsFilePath = fileNameMapper.getInvListsFilePath(dictBTreeFile.getFile().getPath());
         FileReference invListsFile = new FileReference(new File(invListsFilePath));
+        IInvertedListBuilder invListBuilder = invListBuilderFactory.create();
         return new OnDiskInvertedIndex(bufferCache, fileMapProvider, invListBuilder, invListTypeTraits,
                 invListCmpFactories, tokenTypeTraits, tokenCmpFactories, dictBTreeFile, invListsFile);
     }
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexRangeSearchCursor.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexRangeSearchCursor.java
index 372c144..15bc2da 100644
--- a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexRangeSearchCursor.java
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexRangeSearchCursor.java
@@ -97,6 +97,7 @@
             throw new HyracksDataException(e);
         }
         invListCursor.pinPages();
+        invListCursor.hasNext();
         unpinNeeded = true;
         concatTuple.reset();
         concatTuple.addTuple(tokenTuple);
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/util/InvertedIndexUtils.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/util/InvertedIndexUtils.java
index fba2426..02b325a 100644
--- a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/util/InvertedIndexUtils.java
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/util/InvertedIndexUtils.java
@@ -40,10 +40,12 @@
 import edu.uci.ics.hyracks.storage.am.lsm.common.freepage.InMemoryFreePageManager;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.BTreeFactory;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedListBuilder;
+import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedListBuilderFactory;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.impls.LSMInvertedIndex;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.impls.LSMInvertedIndexFileManager;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.inmemory.InMemoryInvertedIndex;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.ondisk.FixedSizeElementInvertedListBuilder;
+import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.ondisk.FixedSizeElementInvertedListBuilderFactory;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.ondisk.OnDiskInvertedIndex;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.ondisk.OnDiskInvertedIndexFactory;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.tokenizers.IBinaryTokenizerFactory;
@@ -98,9 +100,10 @@
         LSMInvertedIndexFileManager fileManager = new LSMInvertedIndexFileManager(ioManager, diskFileMapProvider,
                 onDiskDirFileRef, deletedKeysBTreeFactory);
 
-        IInvertedListBuilder invListBuilder = new FixedSizeElementInvertedListBuilder(invListTypeTraits);
+        IInvertedListBuilderFactory invListBuilderFactory = new FixedSizeElementInvertedListBuilderFactory(
+                invListTypeTraits);
         OnDiskInvertedIndexFactory invIndexFactory = new OnDiskInvertedIndexFactory(diskBufferCache,
-                diskFileMapProvider, invListBuilder, invListTypeTraits, invListCmpFactories, tokenTypeTraits,
+                diskFileMapProvider, invListBuilderFactory, invListTypeTraits, invListCmpFactories, tokenTypeTraits,
                 tokenCmpFactories, fileManager);
 
         LSMInvertedIndex invIndex = new LSMInvertedIndex(memBufferCache, memFreePageManager, invIndexFactory,
diff --git a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/config/AccessMethodTestsConfig.java b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/config/AccessMethodTestsConfig.java
index 26f82a6..a22a989 100644
--- a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/config/AccessMethodTestsConfig.java
+++ b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/config/AccessMethodTestsConfig.java
@@ -69,14 +69,14 @@
     public static final int LSM_BTREE_HYRACKS_FRAME_SIZE = 128;
 
     // Mem configuration for Inverted Index.
-    public static final int LSM_INVINDEX_DISK_PAGE_SIZE = 256;
+    public static final int LSM_INVINDEX_DISK_PAGE_SIZE = 1024;
     public static final int LSM_INVINDEX_DISK_NUM_PAGES = 1000;
     public static final int LSM_INVINDEX_DISK_MAX_OPEN_FILES = 1000;
-    public static final int LSM_INVINDEX_MEM_PAGE_SIZE = 256;
+    public static final int LSM_INVINDEX_MEM_PAGE_SIZE = 1024;
     public static final int LSM_INVINDEX_MEM_NUM_PAGES = 100;
     public static final int LSM_INVINDEX_HYRACKS_FRAME_SIZE = 256;
     // Test parameters.
-    public static final int LSM_INVINDEX_NUM_DOCS_TO_INSERT = 10000;
+    public static final int LSM_INVINDEX_NUM_DOCS_TO_INSERT = 100;
     // Used for full-fledged search test.
     public static final int LSM_INVINDEX_NUM_DOC_QUERIES = 1000;
     public static final int LSM_INVINDEX_NUM_RANDOM_QUERIES = 1000;
@@ -89,7 +89,7 @@
     public static final int LSM_INVINDEX_NUM_DELETE_ROUNDS = 3;
     // Allocate a generous size to make sure we have enough elements for all tests.
     public static final int LSM_INVINDEX_SCAN_COUNT_ARRAY_SIZE = 1000000;
-    public static final int LSM_INVINDEX_MULTITHREAD_NUM_OPERATIONS = 1000;
+    public static final int LSM_INVINDEX_MULTITHREAD_NUM_OPERATIONS = 10000;
     
 }
 
diff --git a/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/LSMInvertedIndexMergeTest.java b/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/LSMInvertedIndexMergeTest.java
index 65ff11f..2b5d8c0 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/LSMInvertedIndexMergeTest.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/LSMInvertedIndexMergeTest.java
@@ -53,15 +53,14 @@
                 } else {
                     LSMInvertedIndexTestUtils.insertIntoInvIndex(testCtx, tupleGen, NUM_DOCS_TO_INSERT);
                 }
-
-                // Perform merge.
-                ILSMIOOperation ioop = invIndexAccessor.createMergeOperation(NoOpIOOperationCallback.INSTANCE);
-                if (ioop != null) {
-                    invIndexAccessor.merge(ioop);
-                }
-                validateAndCheckIndex(testCtx);
-                runTinySearchWorkload(testCtx, tupleGen);
             }
+            // Perform merge.
+            ILSMIOOperation ioop = invIndexAccessor.createMergeOperation(NoOpIOOperationCallback.INSTANCE);
+            if (ioop != null) {
+                invIndexAccessor.merge(ioop);
+            }
+            validateAndCheckIndex(testCtx);
+            runTinySearchWorkload(testCtx, tupleGen);
         }
         
         invIndex.deactivate();
diff --git a/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/multithread/LSMInvertedIndexMultiThreadTest.java b/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/multithread/LSMInvertedIndexMultiThreadTest.java
index 28afc59..8b01a40 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/multithread/LSMInvertedIndexMultiThreadTest.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/multithread/LSMInvertedIndexMultiThreadTest.java
@@ -83,19 +83,16 @@
     protected ArrayList<TestWorkloadConf> getTestWorkloadConf() {
         ArrayList<TestWorkloadConf> workloadConfs = new ArrayList<TestWorkloadConf>();
 
-        /*
         // Insert only workload.
         TestOperation[] insertOnlyOps = new TestOperation[] { TestOperation.INSERT };
         workloadConfs.add(new TestWorkloadConf(insertOnlyOps, ProbabilityHelper
                 .getUniformProbDist(insertOnlyOps.length)));
-        */
 
         // Insert and merge workload.
         TestOperation[] insertMergeOps = new TestOperation[] { TestOperation.INSERT, TestOperation.MERGE };
         workloadConfs.add(new TestWorkloadConf(insertMergeOps, ProbabilityHelper
                 .getUniformProbDist(insertMergeOps.length)));
 
-        /*
         // Inserts mixed with point searches and scans.
         TestOperation[] insertSearchOnlyOps = new TestOperation[] { TestOperation.INSERT, TestOperation.POINT_SEARCH,
                 TestOperation.SCAN };
@@ -123,7 +120,6 @@
         TestOperation[] allOps = new TestOperation[] { TestOperation.INSERT, TestOperation.DELETE,
                 TestOperation.POINT_SEARCH, TestOperation.SCAN, TestOperation.MERGE };
         workloadConfs.add(new TestWorkloadConf(allOps, ProbabilityHelper.getUniformProbDist(allOps.length)));
-        */
 
         return workloadConfs;
     }
@@ -131,7 +127,7 @@
     @Test
     public void wordTokensInvIndexTest() throws IOException, IndexException, InterruptedException {
         String dataMsg = "Documents";
-        int[] numThreads = new int[] { REGULAR_NUM_THREADS };
+        int[] numThreads = new int[] { REGULAR_NUM_THREADS, EXCESSIVE_NUM_THREADS };
         for (int i = 0; i < numThreads.length; i++) {
             for (TestWorkloadConf conf : workloadConfs) {                
                 setUp();
@@ -143,4 +139,20 @@
             }
         }
     }
+    
+    @Test
+    public void hashedNGramTokensInvIndexTest() throws IOException, IndexException, InterruptedException {
+        String dataMsg = "Person Names";
+        int[] numThreads = new int[] { REGULAR_NUM_THREADS, EXCESSIVE_NUM_THREADS };
+        for (int i = 0; i < numThreads.length; i++) {
+            for (TestWorkloadConf conf : workloadConfs) {
+                setUp();
+                LSMInvertedIndexTestContext testCtx = LSMInvertedIndexTestUtils.createHashedNGramInvIndexTestContext(
+                        harness, InvertedIndexType.LSM);
+                TupleGenerator tupleGen = LSMInvertedIndexTestUtils.createPersonNamesTupleGen(harness.getRandom());
+                runTest(testCtx, tupleGen, numThreads[i], conf, dataMsg);
+                tearDown();
+            }
+        }
+    }
 }
diff --git a/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/multithread/LSMInvertedIndexTestWorker.java b/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/multithread/LSMInvertedIndexTestWorker.java
index 09ceb0e..7fede4c 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/multithread/LSMInvertedIndexTestWorker.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/multithread/LSMInvertedIndexTestWorker.java
@@ -70,10 +70,7 @@
         
         switch (op) {
             case INSERT: {
-                accessor.insert(tuple);
-                // Add tuple to document corpus so we can delete it.
-                ITupleReference copyTuple = TupleUtils.copyTuple(tuple);
-                documentCorpus.add(copyTuple);
+                insert(accessor, tuple);
                 break;
             }
 
@@ -87,11 +84,8 @@
                     documentCorpus.set(docIndex, documentCorpus.get(documentCorpus.size() - 1));
                     documentCorpus.remove(documentCorpus.size() - 1);
                 } else {
-                    // Treat this case as an insert.
-                    accessor.insert(tuple);
-                    // Add tuple to document corpus so we can delete it.
-                    ITupleReference copyTuple = TupleUtils.copyTuple(tuple);
-                    documentCorpus.add(copyTuple);
+                    // No existing documents to delete, treat this case as an insert.
+                    insert(accessor, tuple);
                 }
                 break;
             }
@@ -123,12 +117,7 @@
                         accessor.merge(ioop);
                     }
                 } catch (LSMMergeInProgressException e) {
-                    e.printStackTrace();
-                    // Ignore ongoing merges. Do an insert instead.
-                    //accessor.insert(tuple);
-                    // Add tuple to document corpus so we can delete it.
-                    //ITupleReference copyTuple = TupleUtils.copyTuple(tuple);
-                    //documentCorpus.add(copyTuple);
+                    insert(accessor, tuple);
                 }
                 break;
             }
@@ -137,4 +126,12 @@
                 throw new HyracksDataException("Op " + op.toString() + " not supported.");
         }
     }
+    
+    private void insert(LSMInvertedIndexAccessor accessor, ITupleReference tuple) throws HyracksDataException, IndexException {
+        // Ignore ongoing merges. Do an insert instead.
+        accessor.insert(tuple);
+        // Add tuple to document corpus so we can delete it.
+        ITupleReference copyTuple = TupleUtils.copyTuple(tuple);
+        documentCorpus.add(copyTuple);
+    }
 }