diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/ioopcallbacks/AbstractLSMIOOperationCallback.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/ioopcallbacks/AbstractLSMIOOperationCallback.java
index e31fea3..6f7c220 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/ioopcallbacks/AbstractLSMIOOperationCallback.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/ioopcallbacks/AbstractLSMIOOperationCallback.java
@@ -21,6 +21,7 @@
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexMetaDataFrame;
+import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMComponent;
 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.common.buffercache.IBufferCache;
@@ -42,14 +43,14 @@
     }
 
     @Override
-    public synchronized void afterFinalize(ILSMIOOperation operation, Object newComponent) {
+    public synchronized void afterFinalize(ILSMIOOperation operation, ILSMComponent newComponent) {
         // Wake up all blocked index operations that were waiting for this io operation to complete.
         opTracker.notifyAll();
     }
 
-    protected abstract long getComponentLSN(List<Object> oldComponents) throws HyracksDataException;
+    protected abstract long getComponentLSN(List<ILSMComponent> oldComponents) throws HyracksDataException;
     
-    protected void putLSNIntoMetadata(ITreeIndex treeIndex, List<Object> oldComponents) throws HyracksDataException {
+    protected void putLSNIntoMetadata(ITreeIndex treeIndex, List<ILSMComponent> oldComponents) throws HyracksDataException {
         long componentLSN = getComponentLSN(oldComponents);
         int fileId = treeIndex.getFileId();
         IBufferCache bufferCache = treeIndex.getBufferCache();
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/ioopcallbacks/LSMBTreeIOOperationCallback.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/ioopcallbacks/LSMBTreeIOOperationCallback.java
index a29b20c..434e6ef 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/ioopcallbacks/LSMBTreeIOOperationCallback.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/ioopcallbacks/LSMBTreeIOOperationCallback.java
@@ -20,6 +20,8 @@
 import edu.uci.ics.asterix.transaction.management.opcallbacks.IndexOperationTracker;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTree;
+import edu.uci.ics.hyracks.storage.am.lsm.btree.impls.LSMBTreeComponent;
+import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMComponent;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation;
 
 public class LSMBTreeIOOperationCallback extends AbstractLSMIOOperationCallback {
@@ -29,13 +31,14 @@
     }
 
     @Override
-    public void afterOperation(ILSMIOOperation operation, List<Object> oldComponents, Object newComponent) throws HyracksDataException {
-        BTree btree = (BTree) newComponent;
-        putLSNIntoMetadata(btree, oldComponents);
+    public void afterOperation(ILSMIOOperation operation, List<ILSMComponent> oldComponents, ILSMComponent newComponent)
+            throws HyracksDataException {
+        LSMBTreeComponent btreeComponent = (LSMBTreeComponent) newComponent;
+        putLSNIntoMetadata(btreeComponent.getBTree(), oldComponents);
     }
 
     @Override
-    protected long getComponentLSN(List<Object> oldComponents) throws HyracksDataException {
+    protected long getComponentLSN(List<ILSMComponent> oldComponents) throws HyracksDataException {
         if (oldComponents == null) {
             // Implies a flush IO operation.
             return opTracker.getLastLSN();
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/ioopcallbacks/LSMInvertedIndexIOOperationCallback.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/ioopcallbacks/LSMInvertedIndexIOOperationCallback.java
index f5f60f9..b1450c1 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/ioopcallbacks/LSMInvertedIndexIOOperationCallback.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/ioopcallbacks/LSMInvertedIndexIOOperationCallback.java
@@ -19,8 +19,9 @@
 
 import edu.uci.ics.asterix.transaction.management.opcallbacks.IndexOperationTracker;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMComponent;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation;
-import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.impls.LSMInvertedIndex.LSMInvertedIndexComponent;
+import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.impls.LSMInvertedIndexComponent;
 
 public class LSMInvertedIndexIOOperationCallback extends AbstractLSMIOOperationCallback {
 
@@ -29,14 +30,14 @@
     }
 
     @Override
-    public void afterOperation(ILSMIOOperation operation, List<Object> oldComponents, Object newComponent)
+    public void afterOperation(ILSMIOOperation operation, List<ILSMComponent> oldComponents, ILSMComponent newComponent)
             throws HyracksDataException {
         LSMInvertedIndexComponent invIndexComponent = (LSMInvertedIndexComponent) newComponent;
         putLSNIntoMetadata(invIndexComponent.getDeletedKeysBTree(), oldComponents);
     }
 
     @Override
-    protected long getComponentLSN(List<Object> oldComponents) throws HyracksDataException {
+    protected long getComponentLSN(List<ILSMComponent> oldComponents) throws HyracksDataException {
         if (oldComponents == null) {
             // Implies a flush IO operation.
             return opTracker.getLastLSN();
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/ioopcallbacks/LSMRTreeIOOperationCallback.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/ioopcallbacks/LSMRTreeIOOperationCallback.java
index f02c49e..ab3c9a6 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/ioopcallbacks/LSMRTreeIOOperationCallback.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/ioopcallbacks/LSMRTreeIOOperationCallback.java
@@ -19,8 +19,9 @@
 
 import edu.uci.ics.asterix.transaction.management.opcallbacks.IndexOperationTracker;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
+import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMComponent;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation;
-import edu.uci.ics.hyracks.storage.am.lsm.rtree.impls.AbstractLSMRTree.LSMRTreeComponent;
+import edu.uci.ics.hyracks.storage.am.lsm.rtree.impls.LSMRTreeComponent;
 
 public class LSMRTreeIOOperationCallback extends AbstractLSMIOOperationCallback {
 
@@ -29,14 +30,14 @@
     }
 
     @Override
-    public void afterOperation(ILSMIOOperation operation, List<Object> oldComponents, Object newComponent) throws HyracksDataException {
+    public void afterOperation(ILSMIOOperation operation, List<ILSMComponent> oldComponents, ILSMComponent newComponent) throws HyracksDataException {
         LSMRTreeComponent rtreeComponent = (LSMRTreeComponent) newComponent;
         putLSNIntoMetadata(rtreeComponent.getRTree(), oldComponents);
         putLSNIntoMetadata(rtreeComponent.getBTree(), oldComponents);
     }
 
     @Override
-    protected long getComponentLSN(List<Object> oldComponents) throws HyracksDataException {
+    protected long getComponentLSN(List<ILSMComponent> oldComponents) throws HyracksDataException {
         if (oldComponents == null) {
             // Implies a flush IO operation.
             return opTracker.getLastLSN();
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/IndexOperationTracker.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/IndexOperationTracker.java
index d53765e..d6b9dba 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/IndexOperationTracker.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/IndexOperationTracker.java
@@ -30,17 +30,15 @@
     // Number of active operations on a ILSMIndex instance.
     private int numActiveOperations = 0;
     private long lastLsn;
-    private final ILSMIndex index;
-    private final ILSMIndexAccessor accessor;
+    private final ILSMIndex index;    
     private final ILSMIOOperationCallback ioOpCallback;
+    private ILSMIndexAccessor accessor;
 
     public IndexOperationTracker(ILSMIndex index, ILSMIOOperationCallbackFactory ioOpCallbackFactory) {
         this.index = index;
         //TODO 
         //This code is added to avoid NullPointException when the index's comparatorFactory is null.
         //The null comparator factory is set in the constructor of the IndexDropOperatorDescriptor.
-        accessor = (ILSMIndexAccessor) index.createAccessor(NoOpOperationCallback.INSTANCE,
-                NoOpOperationCallback.INSTANCE);
         if (ioOpCallbackFactory != null) {
             ioOpCallback = ioOpCallbackFactory.createIOOperationCallback(this);
         } else {
@@ -93,10 +91,13 @@
         if (opCallback != null) {
             opCallback.decrementLocalNumActiveOperations();
         }
-
         // If we need a flush, and this is the last completing operation, then schedule the flush.
         // Once the flush has completed notify all waiting operations.
         if (index.getFlushController().getFlushStatus(index) && numActiveOperations == 0) {
+            if (accessor == null) {
+                accessor = (ILSMIndexAccessor) index.createAccessor(NoOpOperationCallback.INSTANCE,
+                        NoOpOperationCallback.INSTANCE);
+            }
             index.getIOScheduler().scheduleOperation(accessor.createFlushOperation(ioOpCallback));
         }
     }
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/PrimaryIndexModificationOperationCallback.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/PrimaryIndexModificationOperationCallback.java
index 6e9e936..19e4396 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/PrimaryIndexModificationOperationCallback.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/PrimaryIndexModificationOperationCallback.java
@@ -18,7 +18,6 @@
 import edu.uci.ics.asterix.transaction.management.exception.ACIDException;
 import edu.uci.ics.asterix.transaction.management.service.locking.ILockManager;
 import edu.uci.ics.asterix.transaction.management.service.logging.IndexLogger;
-import edu.uci.ics.asterix.transaction.management.service.transaction.IResourceManager.ResourceType;
 import edu.uci.ics.asterix.transaction.management.service.transaction.TransactionContext;
 import edu.uci.ics.asterix.transaction.management.service.transaction.TransactionManagementConstants.LockManagerConstants.LockMode;
 import edu.uci.ics.asterix.transaction.management.service.transaction.TransactionSubsystem;
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/PrimaryIndexModificationOperationCallbackFactory.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/PrimaryIndexModificationOperationCallbackFactory.java
index be972a7..af1cb9d 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/PrimaryIndexModificationOperationCallbackFactory.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/PrimaryIndexModificationOperationCallbackFactory.java
@@ -17,9 +17,6 @@
 
 import edu.uci.ics.asterix.transaction.management.exception.ACIDException;
 import edu.uci.ics.asterix.transaction.management.resource.TransactionalResourceRepository;
-import edu.uci.ics.asterix.transaction.management.service.logging.IndexResourceManager;
-import edu.uci.ics.asterix.transaction.management.service.transaction.IResourceManager;
-import edu.uci.ics.asterix.transaction.management.service.transaction.IResourceManager.ResourceType;
 import edu.uci.ics.asterix.transaction.management.service.transaction.ITransactionSubsystemProvider;
 import edu.uci.ics.asterix.transaction.management.service.transaction.JobId;
 import edu.uci.ics.asterix.transaction.management.service.transaction.TransactionContext;
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/SecondaryIndexModificationOperationCallback.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/SecondaryIndexModificationOperationCallback.java
index 8c1aac0..fa28c0c 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/SecondaryIndexModificationOperationCallback.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/SecondaryIndexModificationOperationCallback.java
@@ -18,7 +18,6 @@
 import edu.uci.ics.asterix.transaction.management.exception.ACIDException;
 import edu.uci.ics.asterix.transaction.management.service.locking.ILockManager;
 import edu.uci.ics.asterix.transaction.management.service.logging.IndexLogger;
-import edu.uci.ics.asterix.transaction.management.service.transaction.IResourceManager.ResourceType;
 import edu.uci.ics.asterix.transaction.management.service.transaction.TransactionContext;
 import edu.uci.ics.asterix.transaction.management.service.transaction.TransactionSubsystem;
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryHashFunctionFactory;