diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/api/IInvertedIndexFileNameMapper.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/api/IInvertedIndexFileNameMapper.java
new file mode 100644
index 0000000..d7ec129
--- /dev/null
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/api/IInvertedIndexFileNameMapper.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright 2009-2010 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;
+
+/**
+ * Maps from the dictionary BTree file/path to a corresponding inverted-lists file/path.
+ */
+public interface IInvertedIndexFileNameMapper {
+    public String getInvListsFilePath(String dictBTreeFilePath);
+}
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 01ace038..361d954 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
@@ -28,6 +28,7 @@
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
 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;
 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.api.IIndexAccessor;
@@ -43,15 +44,14 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IndexType;
 import edu.uci.ics.hyracks.storage.am.common.dataflow.IIndex;
 import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
-import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMComponentFinalizer;
-import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexFileManager;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMFlushController;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperationCallback;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperationScheduler;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndex;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexAccessor;
+import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexFileManager;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMMergePolicy;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMOperationTracker;
 import edu.uci.ics.hyracks.storage.am.lsm.common.freepage.InMemoryBufferCache;
@@ -62,6 +62,7 @@
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedIndex;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.impls.LSMInvertedIndexFileManager.LSMInvertedIndexFileNameComponent;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.inmemory.InMemoryInvertedIndex;
+import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.inmemory.InMemoryInvertedIndexAccessor;
 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;
@@ -104,7 +105,7 @@
     // For creating inverted indexes in flush and merge.
     protected final OnDiskInvertedIndexFactory diskInvIndexFactory;
     // For creating deleted-keys BTrees in flush and merge.
-    protected final BTreeFactory diskBTreeFactory;
+    protected final BTreeFactory deletedKeysBTreeFactory;
     protected final IBufferCache diskBufferCache;
     protected final IFileMapProvider diskFileMapProvider;
     // List of LSMInvertedIndexComponent instances. Using Object for better sharing via
@@ -139,7 +140,7 @@
         this.tokenizerFactory = tokenizerFactory;
         this.fileManager = fileManager;
         this.diskInvIndexFactory = diskInvIndexFactory;
-        this.diskBTreeFactory = diskBTreeFactory;
+        this.deletedKeysBTreeFactory = diskBTreeFactory;
         this.diskBufferCache = diskInvIndexFactory.getBufferCache();
         this.diskFileMapProvider = diskFileMapProvider;
         this.invListTypeTraits = invListTypeTraits;
@@ -161,30 +162,34 @@
     }
 
     @Override
-    // TODO: Properly implement this one.
     public synchronized void activate() throws HyracksDataException {
         if (isActivated) {
             return;
         }
-
-        ((InMemoryBufferCache) memComponent.getInvIndex().getBufferCache()).open();
-        memComponent.getInvIndex().create();
-        memComponent.getDeletedKeysBTree().create();
-        List<Object> validFileNames = fileManager.cleanupAndGetValidFiles(componentFinalizer);
-        for (Object o : validFileNames) {
-            LSMInvertedIndexFileNameComponent component = (LSMInvertedIndexFileNameComponent) o;
-            FileReference rtreeFile = new FileReference(new File(component.getRTreeFileName()));
-            FileReference btreeFile = new FileReference(new File(component.getBTreeFileName()));
-            RTree rtree = (RTree) createDiskTree(diskRTreeFactory, rtreeFile, false);
-            BTree btree = (BTree) createDiskTree(diskBTreeFactory, btreeFile, false);
-            LSMRTreeComponent diskComponent = new LSMRTreeComponent(rtree, btree);
-            diskComponents.add(diskComponent);
+        try {
+            ((InMemoryBufferCache) memComponent.getInvIndex().getBufferCache()).open();
+            memComponent.getInvIndex().create();
+            memComponent.getDeletedKeysBTree().create();
+            List<Object> validFileNames = fileManager.cleanupAndGetValidFiles(componentFinalizer);
+            for (Object o : validFileNames) {
+                LSMInvertedIndexFileNameComponent component = (LSMInvertedIndexFileNameComponent) o;
+                FileReference dictBTreeFile = new FileReference(new File(component.getDictBTreeFileName()));
+                FileReference deletedKeysBTreeFile = new FileReference(
+                        new File(component.getDeletedKeysBTreeFileName()));
+                IInvertedIndex invIndex = createDiskInvIndex(diskInvIndexFactory, dictBTreeFile, false);
+                BTree deletedKeysBTree = (BTree) createDiskTree(deletedKeysBTreeFactory, deletedKeysBTreeFile, false);
+                LSMInvertedIndexComponent diskComponent = new LSMInvertedIndexComponent(invIndex, deletedKeysBTree);
+                diskComponents.add(diskComponent);
+            }
+            isActivated = true;
+            // TODO: Maybe we can make activate throw an index exception?
+        } catch (IndexException e) {
+            throw new HyracksDataException(e);
         }
-        isActivated = true;
     }
 
-    protected IInvertedIndex createDiskInvIndex(OnDiskInvertedIndexFactory invIndexFactory, FileReference fileRef, boolean create) throws HyracksDataException, IndexException {
-        IInvertedIndex invIndex = invIndexFactory.createIndexInstance(fileRef);
+    protected IInvertedIndex createDiskInvIndex(OnDiskInvertedIndexFactory invIndexFactory, FileReference dictBTreeFileRef, boolean create) throws HyracksDataException, IndexException {
+        IInvertedIndex invIndex = invIndexFactory.createIndexInstance(dictBTreeFileRef);
         if (create) {
             invIndex.create();
         }
@@ -193,8 +198,8 @@
         return invIndex;
     }
     
-    protected ITreeIndex createDiskDeletedKeysBTree(BTreeFactory btreeFactory, FileReference fileRef, boolean create) throws HyracksDataException, IndexException {
-        ITreeIndex btree = btreeFactory.createIndexInstance(fileRef);
+    protected ITreeIndex createDiskTree(BTreeFactory btreeFactory, FileReference btreeFileRef, boolean create) throws HyracksDataException, IndexException {
+        ITreeIndex btree = btreeFactory.createIndexInstance(btreeFileRef);
         if (create) {
             btree.create();
         }
@@ -208,8 +213,7 @@
         if (!isActivated) {
             throw new HyracksDataException("Failed to clear the index since it is not activated.");
         }
-        memComponent.getInvIndex().clear();
-        memComponent.getDeletedKeysBTree().clear();
+        resetInMemoryComponent();
         for (Object o : diskComponents) {
             LSMInvertedIndexComponent component = (LSMInvertedIndexComponent) o;
             component.getInvIndex().deactivate();
@@ -262,28 +266,31 @@
     }
 
     @Override
+    public void validate() throws HyracksDataException {
+        memComponent.getInvIndex().validate();
+        memComponent.getDeletedKeysBTree().validate();
+        for (Object o : diskComponents) {
+            LSMInvertedIndexComponent component = (LSMInvertedIndexComponent) o;
+            component.getInvIndex().validate();
+            component.getDeletedKeysBTree().validate();
+        }
+    }
+
+    @Override
     public IIndexAccessor createAccessor(IModificationOperationCallback modificationCallback,
             ISearchOperationCallback searchCallback) {
         // TODO: Ignore opcallbacks for now.
         return new LSMInvertedIndexAccessor(lsmHarness, createOpContext());
     }
-
-    @Override
-    public void validate() throws HyracksDataException {
-        // TODO Auto-generated method stub
-        
+    
+    private LSMInvertedIndexOpContext createOpContext() {
+        return new LSMInvertedIndexOpContext(memComponent.getInvIndex(), memComponent.getDeletedKeysBTree());
     }
-
+    
     @Override
     public long getInMemorySize() {
-        // TODO Auto-generated method stub
-        return 0;
-    }
-
-    @Override
-    public IIndexBulkLoader createBulkLoader(float fillFactor, boolean verifyInput) throws IndexException {
-        // TODO Auto-generated method stub
-        return null;
+        InMemoryBufferCache memBufferCache = (InMemoryBufferCache) memComponent.getInvIndex().getBufferCache();
+        return memBufferCache.getNumPages() * memBufferCache.getPageSize();
     }
 
     @Override
@@ -300,49 +307,15 @@
     }
 
     @Override
-    public Object flush(ILSMIOOperation operation) throws HyracksDataException, IndexException {
+    public IIndexBulkLoader createBulkLoader(float fillFactor, boolean verifyInput) throws IndexException {
         // TODO Auto-generated method stub
         return null;
     }
-
-    @Override
-    public ILSMFlushController getFlushController() {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public ILSMOperationTracker getOperationTracker() {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public ILSMIOOperationScheduler getIOScheduler() {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    private LSMInvertedIndexOpContext createOpContext() {
-        return new LSMInvertedIndexOpContext(memoryInvertedIndex);
-    }
-
-    @Override
-    public IBufferCache getBufferCache() {
-        return diskBufferCache;
-    }
-
-    @Override
-    public IndexType getIndexType() {
-        return IndexType.INVERTED;
-    }
-
+    
     public boolean insertUpdateOrDelete(ITupleReference tuple, IIndexOpContext ictx) throws HyracksDataException,
             IndexException {
-        // TODO: Only insert is supported for now. Will need the context for later when update and delete 
-        // are also supported.
         LSMInvertedIndexOpContext ctx = (LSMInvertedIndexOpContext) ictx;
-        memAccessor.insert(tuple);
+        ctx.insertAccessor.insert(tuple);
         return true;
     }
 
@@ -413,7 +386,7 @@
 
         // Bulk load the tuples from all diskInvertedIndexes into the new diskInvertedIndex.
         LSMInvertedFileNameComponent fNameComponent = getMergeTargetFileName(mergedComponents);
-        BTree diskBTree = createDiskBTree(fileManager.createMergeFile(fNameComponent.getBTreeFileName()), true);
+        BTree diskBTree = createDiskBTree(fileManager.createMergeFile(fNameComponent.getDictBTreeFileName()), true);
         //    - Create an InvertedIndex instance
         OnDiskInvertedIndex mergedDiskInvertedIndex = createDiskInvertedIndex(
                 fileManager.createMergeFile(fNameComponent.getInvertedFileName()), true, diskBTree);
@@ -453,137 +426,83 @@
     @Override
     public void cleanUpAfterMerge(List<Object> mergedComponents) throws HyracksDataException {
         for (Object o : mergedComponents) {
-            OnDiskInvertedIndex oldInvertedIndex = (OnDiskInvertedIndex) o;
-            BTree oldBTree = oldInvertedIndex.getBTree();
-
-            //delete a diskBTree file.
-            FileReference fileRef = diskFileMapProvider.lookupFileName(oldBTree.getFileId());
-            diskBufferCache.closeFile(oldBTree.getFileId());
-            diskBufferCache.deleteFile(oldBTree.getFileId(), false);
-            oldBTree.close();
-            fileRef.getFile().delete();
-
-            //delete a diskInvertedIndex file.
-            fileRef = diskFileMapProvider.lookupFileName(oldInvertedIndex.getFileId());
-            diskBufferCache.closeFile(oldInvertedIndex.getFileId());
-            diskBufferCache.deleteFile(oldInvertedIndex.getFileId(), false);
-            oldInvertedIndex.close();
-            fileRef.getFile().delete();
+            LSMInvertedIndexComponent component = (LSMInvertedIndexComponent) o;
+            BTree oldDeletedKeysBTree = component.getDeletedKeysBTree();
+            oldDeletedKeysBTree.deactivate();
+            oldDeletedKeysBTree.destroy();
+            IInvertedIndex oldInvIndex = component.getInvIndex();
+            oldInvIndex.deactivate();
+            oldInvIndex.destroy();
         }
     }
 
     @Override
-    public Object flush() throws HyracksDataException, IndexException {
+    public Object flush(ILSMIOOperation operation) throws HyracksDataException, IndexException {
+        LSMInvertedIndexFlushOperation flushOp = (LSMInvertedIndexFlushOperation) operation;
 
-        // ---------------------------------------------------
-        // [Flow]
-        // #. Create a scanCursor for the BTree of the memoryInvertedIndex to iterate all keys in it.
-        // #. Create an diskInvertedIndex where all keys of memoryInvertedIndex will be bulkloaded.
-        //    - Create a BTree instance for diskBTree 
-        //    - Create an InvertedIndex instance
-        // #. Begin the bulkload of the diskInvertedIndex.
-        // #. While iterating the scanCursor, add each key into the diskInvertedIndex in the bulkload mode.
-        // #. End the bulkload.
-        // #. Return the newly created diskInvertedIndex.
-        // ---------------------------------------------------
+        // Create an inverted index instance to be bulk loaded.
+        IInvertedIndex diskInvertedIndex = createDiskInvIndex(diskInvIndexFactory, flushOp.getDictBTreeFlushTarget(),
+                true);
 
-        // #. Create a scanCursor of memoryInvertedIndex to iterate all keys in it.
-        BTree inMemBtree = ((InMemoryInvertedIndex) memoryInvertedIndex).getBTree();
-        IIndexAccessor btreeAccessor = inMemBtree.createAccessor();
-        MultiComparator btreeMultiComparator = MultiComparator.create(inMemBtree.getComparatorFactories());
-        RangePredicate scanPred = new RangePredicate(null, null, true, true, btreeMultiComparator, btreeMultiComparator);
+        // Create a scan cursor on the BTree underlying the in-memory inverted index.
+        InMemoryInvertedIndexAccessor memInvIndexAccessor = (InMemoryInvertedIndexAccessor) memComponent.getInvIndex()
+                .createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
+        BTreeAccessor memBTreeAccessor = memInvIndexAccessor.getBTreeAccessor();
+        RangePredicate nullPred = new RangePredicate(null, null, true, true, null, null);
+        IIndexCursor scanCursor = memBTreeAccessor.createSearchCursor();
+        memBTreeAccessor.search(scanCursor, nullPred);
 
-        IIndexCursor scanCursor = btreeAccessor.createSearchCursor();
-        btreeAccessor.search(scanCursor, scanPred);
-
-        // #. Create a diskInvertedIndex where all keys of memoryInvertedIndex will be bulkloaded.
-        //    - Create a BTree instance for diskBTree
-        LSMInvertedFileNameComponent fNameComponent = (LSMInvertedFileNameComponent) fileManager.getRelFlushFileName();
-        BTree diskBTree = createDiskBTree(fileManager.createFlushFile(fNameComponent.getBTreeFileName()), true);
-        //    - Create an InvertedIndex instance
-        OnDiskInvertedIndex diskInvertedIndex = createDiskInvertedIndex(
-                fileManager.createFlushFile(fNameComponent.getInvertedFileName()), true, diskBTree);
-
-        // #. Begin the bulkload of the diskInvertedIndex.
-        IIndexBulkLoadContext bulkLoadCtx = diskInvertedIndex.beginBulkLoad(1.0f);
+        // Bulk load the disk inverted index from the in-memory inverted index.
+        IIndexBulkLoader invIndexBulkLoader = diskInvertedIndex.createBulkLoader(1.0f, false);
         try {
             while (scanCursor.hasNext()) {
                 scanCursor.next();
-                diskInvertedIndex.bulkLoadAddTuple(scanCursor.getTuple(), bulkLoadCtx);
+                invIndexBulkLoader.add(scanCursor.getTuple());
             }
         } finally {
             scanCursor.close();
         }
-        diskInvertedIndex.endBulkLoad(bulkLoadCtx);
+        invIndexBulkLoader.end();
 
-        return diskInvertedIndex;
-    }
+        // Create an BTree instance for the deleted keys.
+        BTree diskDeletedKeysBTree = (BTree) createDiskTree(deletedKeysBTreeFactory,
+                flushOp.getDeletedKeysBTreeFlushTarget(), true);
 
-    private BTree createBTreeFlushTarget() throws HyracksDataException {
-        LSMInvertedFileNameComponent fNameComponent = (LSMInvertedFileNameComponent) fileManager.getRelFlushFileName();
-        FileReference fileRef = fileManager.createFlushFile(fNameComponent.getBTreeFileName());
-        return createDiskBTree(fileRef, true);
-    }
+        // Create a scan cursor on the deleted keys BTree underlying the in-memory inverted index.
+        IIndexAccessor deletedKeysBTreeAccessor = (InMemoryInvertedIndexAccessor) memComponent.getDeletedKeysBTree()
+                .createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
+        IIndexCursor deletedKeysScanCursor = deletedKeysBTreeAccessor.createSearchCursor();
+        deletedKeysBTreeAccessor.search(deletedKeysScanCursor, nullPred);
 
-    private BTree createDiskBTree(FileReference fileRef, boolean createBTree) throws HyracksDataException {
-        // File will be deleted during cleanup of merge().
-        diskBufferCache.createFile(fileRef);
-        int diskBTreeFileId = diskFileMapProvider.lookupFileId(fileRef);
-        // File will be closed during cleanup of merge().
-        diskBufferCache.openFile(diskBTreeFileId);
-        // Create new BTree instance.
-        BTree diskBTree = diskBTreeFactory.createIndexInstance();
-        if (createBTree) {
-            diskBTree.create(diskBTreeFileId);
+        // Bulk load the deleted-keys BTree.
+        IIndexBulkLoader deletedKeysBTreeBulkLoader = diskDeletedKeysBTree.createBulkLoader(1.0f, false);
+        try {
+            while (deletedKeysScanCursor.hasNext()) {
+                deletedKeysScanCursor.next();
+                deletedKeysBTreeBulkLoader.add(deletedKeysScanCursor.getTuple());
+            }
+        } finally {
+            deletedKeysScanCursor.close();
         }
-        // BTree will be closed during cleanup of merge().
-        diskBTree.open(diskBTreeFileId);
-        return diskBTree;
-    }
+        deletedKeysBTreeBulkLoader.end();
 
-    private OnDiskInvertedIndex createInvertedIndexFlushTarget(BTree diskBTree) throws HyracksDataException {
-        FileReference fileRef = fileManager.createFlushFile((String) fileManager.getRelFlushFileName());
-        return createDiskInvertedIndex(fileRef, true, diskBTree);
-    }
-
-    private OnDiskInvertedIndex createDiskInvertedIndex(FileReference fileRef, boolean createInvertedIndex, BTree diskBTree)
-            throws HyracksDataException {
-        // File will be deleted during cleanup of merge().
-        diskBufferCache.createFile(fileRef);
-        int diskInvertedIndexFileId = diskFileMapProvider.lookupFileId(fileRef);
-        // File will be closed during cleanup of merge().
-        diskBufferCache.openFile(diskInvertedIndexFileId);
-        // Create new InvertedIndex instance.
-        OnDiskInvertedIndex diskInvertedIndex = (OnDiskInvertedIndex) diskInvertedIndexFactory.createIndexInstance(diskBTree);
-        if (createInvertedIndex) {
-            diskInvertedIndex.create(diskInvertedIndexFileId);
-        }
-        // InvertedIndex will be closed during cleanup of merge().
-        diskInvertedIndex.open(diskInvertedIndexFileId);
-        return diskInvertedIndex;
+        return new LSMInvertedIndexComponent(diskInvertedIndex, diskDeletedKeysBTree);
     }
 
     public void addFlushedComponent(Object index) {
-        diskInvertedIndexList.addFirst(index);
+        diskComponents.addFirst(index);
     }
 
     @Override
     public InMemoryFreePageManager getInMemoryFreePageManager() {
-        // TODO This code should be changed more generally if IInMemoryInvertedIndex interface is defined and
-        //      InMemoryBtreeInvertedIndex implements IInMemoryInvertedIndex
-        InMemoryInvertedIndex memoryBTreeInvertedIndex = (InMemoryInvertedIndex) memoryInvertedIndex;
-        return (InMemoryFreePageManager) memoryBTreeInvertedIndex.getBTree().getFreePageManager();
+        return memFreePageManager;
     }
 
     @Override
     public void resetInMemoryComponent() throws HyracksDataException {
-        // TODO This code should be changed more generally if IInMemoryInvertedIndex interface is defined and
-        //      InMemoryBtreeInvertedIndex implements IInMemoryInvertedIndex
-        InMemoryInvertedIndex memoryBTreeInvertedIndex = (InMemoryInvertedIndex) memoryInvertedIndex;
-        BTree memBTree = memoryBTreeInvertedIndex.getBTree();
-        InMemoryFreePageManager memFreePageManager = (InMemoryFreePageManager) memBTree.getFreePageManager();
         memFreePageManager.reset();
-        memBTree.create(memBTree.getFileId());
+        memComponent.getInvIndex().clear();
+        memComponent.getDeletedKeysBTree().clear();
     }
 
     @Override
@@ -595,4 +514,29 @@
     public ILSMComponentFinalizer getComponentFinalizer() {
         return componentFinalizer;
     }
+    
+    @Override
+    public ILSMFlushController getFlushController() {
+        return lsmHarness.getFlushController();
+    }
+
+    @Override
+    public ILSMOperationTracker getOperationTracker() {
+        return lsmHarness.getOperationTracker();
+    }
+
+    @Override
+    public ILSMIOOperationScheduler getIOScheduler() {
+        return lsmHarness.getIOScheduler();
+    }
+
+    @Override
+    public IBufferCache getBufferCache() {
+        return diskBufferCache;
+    }
+
+    @Override
+    public IndexType getIndexType() {
+        return IndexType.INVERTED;
+    }
 }
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexFileManager.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexFileManager.java
index 26fd72e..1132f36 100644
--- a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexFileManager.java
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexFileManager.java
@@ -31,20 +31,21 @@
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMComponentFinalizer;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.LSMIndexFileManager;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.TreeIndexFactory;
+import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedIndexFileNameMapper;
 import edu.uci.ics.hyracks.storage.common.file.IFileMapProvider;
 
-// TODO: Implement this one properly!
-public class LSMInvertedIndexFileManager extends LSMIndexFileManager {
-    private static final String BTREE_SUFFIX = "b";
+// TODO: Refactor for better code sharing with other file managers.
+public class LSMInvertedIndexFileManager extends LSMIndexFileManager implements IInvertedIndexFileNameMapper {
+    private static final String DICT_BTREE_SUFFIX = "b";
     private static final String INVLISTS_SUFFIX = "i";
     private static final String DELETED_KEYS_BTREE_SUFFIX = "d";
 
-    private final TreeIndexFactory<? extends ITreeIndex> rtreeFactory;
+    // We only need a BTree factory because the inverted indexes consistency is validated against its dictionary BTree.
     private final TreeIndexFactory<? extends ITreeIndex> btreeFactory;
 
-    private static FilenameFilter btreeFilter = new FilenameFilter() {
+    private static FilenameFilter dictBTreeFilter = new FilenameFilter() {
         public boolean accept(File dir, String name) {
-            return !name.startsWith(".") && name.endsWith(BTREE_SUFFIX);
+            return !name.startsWith(".") && name.endsWith(DICT_BTREE_SUFFIX);
         }
     };
 
@@ -55,32 +56,29 @@
     };
 
     public LSMInvertedIndexFileManager(IIOManager ioManager, IFileMapProvider fileMapProvider, FileReference file,
-            TreeIndexFactory<? extends ITreeIndex> rtreeFactory, TreeIndexFactory<? extends ITreeIndex> btreeFactory) {
+            TreeIndexFactory<? extends ITreeIndex> btreeFactory) {
         super(ioManager, fileMapProvider, file, null);
-        this.rtreeFactory = rtreeFactory;
         this.btreeFactory = btreeFactory;
     }
 
     @Override
     public Object getRelFlushFileName() {
         String baseName = (String) super.getRelFlushFileName();
-        return new LSMInvertedIndexFileNameComponent(baseName + SPLIT_STRING + BTREE_SUFFIX, baseName + SPLIT_STRING
-                + INVLISTS_SUFFIX, baseName + DELETED_KEYS_BTREE_SUFFIX);
+        return new LSMInvertedIndexFileNameComponent(baseName + SPLIT_STRING + DICT_BTREE_SUFFIX, baseName
+                + DELETED_KEYS_BTREE_SUFFIX);
 
     }
 
     @Override
     public Object getRelMergeFileName(String firstFileName, String lastFileName) throws HyracksDataException {
         String baseName = (String) super.getRelMergeFileName(firstFileName, lastFileName);
-        return new LSMInvertedIndexFileNameComponent(baseName + SPLIT_STRING + BTREE_SUFFIX, baseName + SPLIT_STRING
-                + INVLISTS_SUFFIX, baseName + DELETED_KEYS_BTREE_SUFFIX);
+        return new LSMInvertedIndexFileNameComponent(baseName + SPLIT_STRING + DICT_BTREE_SUFFIX, baseName + DELETED_KEYS_BTREE_SUFFIX);
     }
 
     @Override
     public List<Object> cleanupAndGetValidFiles(ILSMComponentFinalizer componentFinalizer) throws HyracksDataException {
         List<Object> validFiles = new ArrayList<Object>();
-        ArrayList<ComparableFileName> allBTreeFiles = new ArrayList<ComparableFileName>();
-        ArrayList<ComparableFileName> allInvListsFiles = new ArrayList<ComparableFileName>();
+        ArrayList<ComparableFileName> allDictBTreeFiles = new ArrayList<ComparableFileName>();
         ArrayList<ComparableFileName> allDeletedKeysBTreeFiles = new ArrayList<ComparableFileName>();
 
         // Gather files from all IODeviceHandles.
@@ -88,27 +86,26 @@
             cleanupAndGetValidFilesInternal(dev, deletedKeysBTreeFilter, btreeFactory, componentFinalizer,
                     allDeletedKeysBTreeFiles);
             HashSet<String> deletedKeysBTreeFilesSet = new HashSet<String>();
-            for (ComparableFileName cmpFileName : allBTreeFiles) {
+            for (ComparableFileName cmpFileName : allDictBTreeFiles) {
                 int index = cmpFileName.fileName.lastIndexOf(SPLIT_STRING);
                 deletedKeysBTreeFilesSet.add(cmpFileName.fileName.substring(0, index));
             }
             // We use the dictionary BTree of the inverted index for validation.
             // List of valid dictionary BTree files that may or may not have a deleted-keys BTree buddy. Will check for buddies below.
             ArrayList<ComparableFileName> tmpAllBTreeFiles = new ArrayList<ComparableFileName>();
-            // TODO: Fix factory.
-            cleanupAndGetValidFilesInternal(dev, btreeFilter, rtreeFactory, componentFinalizer, tmpAllBTreeFiles);
+            cleanupAndGetValidFilesInternal(dev, dictBTreeFilter, btreeFactory, componentFinalizer, tmpAllBTreeFiles);
             // Look for buddy deleted-keys BTrees for all valid dictionary BTrees. 
             // If no buddy is found, delete the file, otherwise add the dictionary BTree to allBTreeFiles. 
             for (ComparableFileName cmpFileName : tmpAllBTreeFiles) {
                 int index = cmpFileName.fileName.lastIndexOf(SPLIT_STRING);
                 String file = cmpFileName.fileName.substring(0, index);
                 if (deletedKeysBTreeFilesSet.contains(file)) {
-                    allBTreeFiles.add(cmpFileName);
+                    allDictBTreeFiles.add(cmpFileName);
                 } else {
                     // Couldn't find the corresponding BTree file; thus, delete
                     // the deleted-keys BTree file.
                     // There is no need to delete the inverted-lists file corresponding to the non-existent
-                    // dictionary BTree, because we flush the dictionary BTree first. So if it a dictionary BTree 
+                    // dictionary BTree, because we flush the dictionary BTree first. So if a dictionary BTree 
                     // file does not exists, then neither can its inverted-list file.
                     File invalidDeletedKeysBTreeFile = new File(cmpFileName.fullPath);
                     invalidDeletedKeysBTreeFile.delete();
@@ -116,48 +113,47 @@
             }
         }
         // Sanity check.
-        if (allBTreeFiles.size() != allDeletedKeysBTreeFiles.size()) {
+        if (allDictBTreeFiles.size() != allDeletedKeysBTreeFiles.size()) {
             throw new HyracksDataException("Unequal number of valid RTree and BTree files found. Aborting cleanup.");
         }
 
         // Trivial cases.
-        if (allBTreeFiles.isEmpty() || allDeletedKeysBTreeFiles.isEmpty()) {
+        if (allDictBTreeFiles.isEmpty() || allDeletedKeysBTreeFiles.isEmpty()) {
             return validFiles;
         }
 
-        // TODO: Continue from here.
-        if (allBTreeFiles.size() == 1 && allDeletedKeysBTreeFiles.size() == 1) {
-            validFiles.add(new LSMInvertedIndexFileNameComponent(allRTreeFiles.get(0).fullPath,
-                    allBTreeFiles.get(0).fullPath));
+        if (allDictBTreeFiles.size() == 1 && allDeletedKeysBTreeFiles.size() == 1) {
+            validFiles.add(new LSMInvertedIndexFileNameComponent(allDictBTreeFiles.get(0).fullPath,
+                    allDeletedKeysBTreeFiles.get(0).fullPath));
             return validFiles;
         }
 
         // Sorts files names from earliest to latest timestamp.
         Collections.sort(allDeletedKeysBTreeFiles);
-        Collections.sort(allBTreeFiles);
+        Collections.sort(allDictBTreeFiles);
 
-        List<ComparableFileName> validComparableRTreeFiles = new ArrayList<ComparableFileName>();
-        ComparableFileName lastRTree = allRTreeFiles.get(0);
-        validComparableRTreeFiles.add(lastRTree);
+        List<ComparableFileName> validComparableDictBTreeFiles = new ArrayList<ComparableFileName>();
+        ComparableFileName lastDictBTree = allDictBTreeFiles.get(0);
+        validComparableDictBTreeFiles.add(lastDictBTree);
 
-        List<ComparableFileName> validComparableBTreeFiles = new ArrayList<ComparableFileName>();
-        ComparableFileName lastBTree = allBTreeFiles.get(0);
-        validComparableBTreeFiles.add(lastBTree);
+        List<ComparableFileName> validComparableDeletedKeysBTreeFiles = new ArrayList<ComparableFileName>();
+        ComparableFileName lastDeletedKeysBTree = allDeletedKeysBTreeFiles.get(0);
+        validComparableDeletedKeysBTreeFiles.add(lastDeletedKeysBTree);
 
-        for (int i = 1; i < allRTreeFiles.size(); i++) {
-            ComparableFileName currentRTree = allRTreeFiles.get(i);
-            ComparableFileName currentBTree = allBTreeFiles.get(i);
+        for (int i = 1; i < allDictBTreeFiles.size(); i++) {
+            ComparableFileName currentRTree = allDictBTreeFiles.get(i);
+            ComparableFileName currentBTree = allDictBTreeFiles.get(i);
             // Current start timestamp is greater than last stop timestamp.
-            if (currentRTree.interval[0].compareTo(lastRTree.interval[1]) > 0
-                    && currentBTree.interval[0].compareTo(lastBTree.interval[1]) > 0) {
-                validComparableRTreeFiles.add(currentRTree);
-                validComparableBTreeFiles.add(currentBTree);
-                lastRTree = currentRTree;
-                lastBTree = currentBTree;
-            } else if (currentRTree.interval[0].compareTo(lastRTree.interval[0]) >= 0
-                    && currentRTree.interval[1].compareTo(lastRTree.interval[1]) <= 0
-                    && currentBTree.interval[0].compareTo(lastBTree.interval[0]) >= 0
-                    && currentBTree.interval[1].compareTo(lastBTree.interval[1]) <= 0) {
+            if (currentRTree.interval[0].compareTo(lastDeletedKeysBTree.interval[1]) > 0
+                    && currentBTree.interval[0].compareTo(lastDeletedKeysBTree.interval[1]) > 0) {
+                validComparableDictBTreeFiles.add(currentRTree);
+                validComparableDeletedKeysBTreeFiles.add(currentBTree);
+                lastDictBTree = currentRTree;
+                lastDeletedKeysBTree = currentBTree;
+            } else if (currentRTree.interval[0].compareTo(lastDictBTree.interval[0]) >= 0
+                    && currentRTree.interval[1].compareTo(lastDictBTree.interval[1]) <= 0
+                    && currentBTree.interval[0].compareTo(lastDeletedKeysBTree.interval[0]) >= 0
+                    && currentBTree.interval[1].compareTo(lastDeletedKeysBTree.interval[1]) <= 0) {
                 // Invalid files are completely contained in last interval.
                 File invalidRTreeFile = new File(currentRTree.fullPath);
                 invalidRTreeFile.delete();
@@ -171,37 +167,43 @@
 
         // Sort valid files in reverse lexicographical order, such that newer
         // files come first.
-        Collections.sort(validComparableRTreeFiles, recencyCmp);
-        Collections.sort(validComparableBTreeFiles, recencyCmp);
+        Collections.sort(validComparableDictBTreeFiles, recencyCmp);
+        Collections.sort(validComparableDeletedKeysBTreeFiles, recencyCmp);
 
-        Iterator<ComparableFileName> rtreeFileIter = validComparableRTreeFiles.iterator();
-        Iterator<ComparableFileName> btreeFileIter = validComparableBTreeFiles.iterator();
-        while (rtreeFileIter.hasNext() && btreeFileIter.hasNext()) {
-            ComparableFileName cmpRTreeFileName = rtreeFileIter.next();
-            ComparableFileName cmpBTreeFileName = btreeFileIter.next();
-            validFiles.add(new LSMInvertedIndexFileNameComponent(cmpRTreeFileName.fullPath, cmpBTreeFileName.fullPath));
+        Iterator<ComparableFileName> dictBTreeFileIter = validComparableDictBTreeFiles.iterator();
+        Iterator<ComparableFileName> deletedKeysBTreeIter = validComparableDeletedKeysBTreeFiles.iterator();
+        while (dictBTreeFileIter.hasNext() && deletedKeysBTreeIter.hasNext()) {
+            ComparableFileName cmpDictBTreeFile = dictBTreeFileIter.next();
+            ComparableFileName cmpDeletedKeysBTreeFile = deletedKeysBTreeIter.next();
+            validFiles.add(new LSMInvertedIndexFileNameComponent(cmpDictBTreeFile.fullPath,
+                    cmpDeletedKeysBTreeFile.fullPath));
         }
 
         return validFiles;
     }
 
+    @Override
+    public String getInvListsFilePath(String dictBTreeFilePath) {
+        int index = dictBTreeFilePath.lastIndexOf(SPLIT_STRING);
+        String file = dictBTreeFilePath.substring(0, index);
+        return file + SPLIT_STRING + INVLISTS_SUFFIX;
+    }
+
+    /**
+     * No need to store the inverted-lists file name because it can be mapped from the
+     * dictionary BTree file name. 
+     */
     public class LSMInvertedIndexFileNameComponent {
-        private final String btreeFileName;
-        private final String invListsFileName;
+        private final String dictBTreeFileName;
         private final String deletedKeysBTreeFileName;
 
-        LSMInvertedIndexFileNameComponent(String btreeFileName, String invListsFileName, String deletedKeysBTreeFileName) {
-            this.btreeFileName = btreeFileName;
-            this.invListsFileName = invListsFileName;
+        LSMInvertedIndexFileNameComponent(String dictBTreeFileName, String deletedKeysBTreeFileName) {
+            this.dictBTreeFileName = dictBTreeFileName;
             this.deletedKeysBTreeFileName = deletedKeysBTreeFileName;
         }
 
-        public String getBTreeFileName() {
-            return btreeFileName;
-        }
-
-        public String getInvListsFileName() {
-            return invListsFileName;
+        public String getDictBTreeFileName() {
+            return dictBTreeFileName;
         }
 
         public String getDeletedKeysBTreeFileName() {
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexFlushOperation.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexFlushOperation.java
new file mode 100644
index 0000000..3055f52
--- /dev/null
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexFlushOperation.java
@@ -0,0 +1,74 @@
+/*
+ * 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.impls;
+
+import java.util.Collections;
+import java.util.List;
+
+import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+import edu.uci.ics.hyracks.api.io.FileReference;
+import edu.uci.ics.hyracks.api.io.IODeviceHandle;
+import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
+import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
+import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation;
+import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperationCallback;
+import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndex;
+import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexAccessor;
+
+public class LSMInvertedIndexFlushOperation implements ILSMIOOperation {
+    private final ILSMIndex index;
+    private final FileReference dictBTreeFlushTarget;
+    private final FileReference deletedKeysBTreeFlushTarget;
+    private final ILSMIOOperationCallback callback;
+
+    public LSMInvertedIndexFlushOperation(ILSMIndex index, FileReference dictBTreeFlushTarget,
+            FileReference deletedKeysBTreeFlushTarget, ILSMIOOperationCallback callback) {
+        this.index = index;
+        this.dictBTreeFlushTarget = dictBTreeFlushTarget;
+        this.deletedKeysBTreeFlushTarget = deletedKeysBTreeFlushTarget;
+        this.callback = callback;
+    }
+
+    @Override
+    public List<IODeviceHandle> getReadDevices() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public List<IODeviceHandle> getWriteDevices() {
+        return Collections.singletonList(dictBTreeFlushTarget.getDevideHandle());
+    }
+
+    @Override
+    public void perform() throws HyracksDataException, IndexException {
+        ILSMIndexAccessor accessor = (ILSMIndexAccessor) index.createAccessor(NoOpOperationCallback.INSTANCE,
+                NoOpOperationCallback.INSTANCE);
+        accessor.flush(this);
+    }
+
+    @Override
+    public ILSMIOOperationCallback getCallback() {
+        return callback;
+    }
+
+    public FileReference getDictBTreeFlushTarget() {
+        return dictBTreeFlushTarget;
+    }
+
+    public FileReference getDeletedKeysBTreeFlushTarget() {
+        return deletedKeysBTreeFlushTarget;
+    }
+}
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexOpContext.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexOpContext.java
index 3ea50e0..1e961e9 100644
--- a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexOpContext.java
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexOpContext.java
@@ -15,12 +15,14 @@
 
 package edu.uci.ics.hyracks.storage.am.lsm.invertedindex.impls;
 
-import edu.uci.ics.hyracks.storage.am.btree.impls.BTree;
+import edu.uci.ics.hyracks.storage.am.common.api.IIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexOpContext;
+import edu.uci.ics.hyracks.storage.am.common.dataflow.IIndex;
+import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.IndexOp;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedIndex;
-import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.inmemory.InMemoryInvertedIndex;
+import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedIndexAccessor;
 
 public class LSMInvertedIndexOpContext implements IIndexOpContext {
     
@@ -28,22 +30,45 @@
     private final MultiComparator cmp;
     private final int invListFieldCount;
     private final int tokenFieldCount;
+    private final IInvertedIndex memInvIndex;
+    private final IIndex memDeletedKeysBTree;
     
-    public LSMInvertedIndexOpContext(IInvertedIndex memoryInvertedIndex) {
-    	InMemoryInvertedIndex memoryBTreeInvertedIndex = (InMemoryInvertedIndex)memoryInvertedIndex;
-    	BTree btree = memoryBTreeInvertedIndex.getBTree();
+    // Accessor to the in-memory inverted index.
+    public IInvertedIndexAccessor insertAccessor;
+    // Accessor to the deleted-keys BTree.
+    public IIndexAccessor deleteAccessor;
+    
+    public LSMInvertedIndexOpContext(IInvertedIndex memInvIndex, IIndex memDeletedKeysBTree) {
+        this.memInvIndex = memInvIndex;
+        this.memDeletedKeysBTree = memDeletedKeysBTree;
+        /*
     	this.cmp = MultiComparator.create(btree.getComparatorFactories());
     	this.invListFieldCount = memoryBTreeInvertedIndex.getInvListCmpFactories().length;
     	this.tokenFieldCount = cmp.getKeyFieldCount() - invListFieldCount;
+    	*/
     }
     
     @Override
     public void reset() {
-        // TODO Auto-generated method stub
     }
 
     @Override
+    // TODO: Ignore opcallback for now.
     public void reset(IndexOp newOp) {
+        switch (newOp) {
+            case INSERT: {
+                if (insertAccessor == null) {
+                    insertAccessor = (IInvertedIndexAccessor) memInvIndex.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
+                }
+                break;
+            }
+            case DELETE: {
+                if (deleteAccessor == null) {
+                    deleteAccessor = memDeletedKeysBTree.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
+                }
+                break;
+            }
+        }
         op = newOp;
     }
     
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/InMemoryInvertedIndexAccessor.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/InMemoryInvertedIndexAccessor.java
index 4a97465..f4f48d2 100644
--- a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/InMemoryInvertedIndexAccessor.java
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/InMemoryInvertedIndexAccessor.java
@@ -81,6 +81,10 @@
         return searcher;
     }
     
+    public BTreeAccessor getBTreeAccessor() {
+        return btreeAccessor;
+    }
+    
     @Override
     public void delete(ITupleReference tuple) throws HyracksDataException, IndexException {
         throw new UnsupportedOperationException("Delete not supported by in-memory inverted index.");
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 bd2605c..b044ebe 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
@@ -23,6 +23,7 @@
 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.common.buffercache.IBufferCache;
 import edu.uci.ics.hyracks.storage.common.file.IFileMapProvider;
 
@@ -33,23 +34,26 @@
     protected final IBinaryComparatorFactory[] invListCmpFactories;
     protected final ITypeTraits[] tokenTypeTraits;
     protected final IBinaryComparatorFactory[] tokenCmpFactories;
+    protected final IInvertedIndexFileNameMapper fileNameMapper;
 
     public OnDiskInvertedIndexFactory(IBufferCache bufferCache, IFileMapProvider fileMapProvider,
             IInvertedListBuilder invListBuilder, ITypeTraits[] invListTypeTraits,
             IBinaryComparatorFactory[] invListCmpFactories, ITypeTraits[] tokenTypeTraits,
-            IBinaryComparatorFactory[] tokenCmpFactories) {
+            IBinaryComparatorFactory[] tokenCmpFactories, IInvertedIndexFileNameMapper fileNameMapper) {
         super(bufferCache, fileMapProvider, null);
         this.invListBuilder = invListBuilder;
         this.invListTypeTraits = invListTypeTraits;
         this.invListCmpFactories = invListCmpFactories;
         this.tokenTypeTraits = tokenTypeTraits;
         this.tokenCmpFactories = tokenCmpFactories;
+        this.fileNameMapper = fileNameMapper;
     }
 
     @Override
-    public IInvertedIndex createIndexInstance(FileReference file) throws IndexException {
-        FileReference btreeFile = new FileReference(new File(file.getFile().getPath() + "_btree"));
-        return new OnDiskInvertedIndex(bufferCache, fileMapProvider, invListBuilder, invListTypeTraits, invListCmpFactories,
-                tokenTypeTraits, tokenCmpFactories, btreeFile, file);
+    public IInvertedIndex createIndexInstance(FileReference dictBTreeFile) throws IndexException {
+        String invListsFilePath = fileNameMapper.getInvListsFilePath(dictBTreeFile.getFile().getPath());
+        FileReference invListsFile = new FileReference(new File(invListsFilePath));
+        return new OnDiskInvertedIndex(bufferCache, fileMapProvider, invListBuilder, invListTypeTraits,
+                invListCmpFactories, tokenTypeTraits, tokenCmpFactories, dictBTreeFile, invListsFile);
     }
 }