diff --git a/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/am/btree/BTreePrimaryIndexScanOperatorTest.java b/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/am/btree/BTreePrimaryIndexScanOperatorTest.java
index 34a4d50..36b1364 100644
--- a/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/am/btree/BTreePrimaryIndexScanOperatorTest.java
+++ b/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/am/btree/BTreePrimaryIndexScanOperatorTest.java
@@ -42,7 +42,7 @@
     @Before
     public void setup() throws Exception {
         super.setup();
-	createPrimaryIndex();
+        createPrimaryIndex();
         loadPrimaryIndex();
     }
 
diff --git a/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/am/btree/BTreePrimaryIndexSearchOperatorTest.java b/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/am/btree/BTreePrimaryIndexSearchOperatorTest.java
index 304bbef..661e057 100644
--- a/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/am/btree/BTreePrimaryIndexSearchOperatorTest.java
+++ b/hyracks-examples/hyracks-integration-tests/src/test/java/edu/uci/ics/hyracks/tests/am/btree/BTreePrimaryIndexSearchOperatorTest.java
@@ -42,7 +42,7 @@
     @Before
     public void setup() throws Exception {
         super.setup();
-	createPrimaryIndex();
+        createPrimaryIndex();
         loadPrimaryIndex();
     }
 
diff --git a/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/dataflow/BTreeDataflowHelper.java b/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/dataflow/BTreeDataflowHelper.java
index 699915d..41a63a6 100644
--- a/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/dataflow/BTreeDataflowHelper.java
+++ b/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/dataflow/BTreeDataflowHelper.java
@@ -32,8 +32,7 @@
     @Override
     public ITreeIndex createIndexInstance() throws HyracksDataException {
         try {
-            return BTreeUtils.createBTree(opDesc.getStorageManager().getBufferCache(ctx), opDesc
-                    .getOpCallbackProvider().getOperationCallback(), treeOpDesc.getTreeIndexTypeTraits(), treeOpDesc
+            return BTreeUtils.createBTree(opDesc.getStorageManager().getBufferCache(ctx), treeOpDesc.getTreeIndexTypeTraits(), treeOpDesc
                     .getTreeIndexComparatorFactories(), BTreeLeafFrameType.REGULAR_NSM);
         } catch (BTreeException e) {
             throw new HyracksDataException(e);
diff --git a/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/impls/BTree.java b/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/impls/BTree.java
index 397d95a..b9a3863 100644
--- a/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/impls/BTree.java
+++ b/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/impls/BTree.java
@@ -33,7 +33,8 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IFreePageManager;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexBulkLoadContext;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexCursor;
-import edu.uci.ics.hyracks.storage.am.common.api.IOperationCallback;
+import edu.uci.ics.hyracks.storage.am.common.api.IModificationOperationCallback;
+import edu.uci.ics.hyracks.storage.am.common.api.ISearchOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.api.ISearchPredicate;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexAccessor;
@@ -63,7 +64,6 @@
 
     private final IFreePageManager freePageManager;
     private final IBufferCache bufferCache;
-    private final IOperationCallback opCallback;
     private final ITreeIndexFrameFactory interiorFrameFactory;
     private final ITreeIndexFrameFactory leafFrameFactory;
     private final int fieldCount;
@@ -71,11 +71,10 @@
     private final ReadWriteLock treeLatch;
     private int fileId;
 
-    public BTree(IBufferCache bufferCache, IOperationCallback opCallback, int fieldCount,
-            IBinaryComparatorFactory[] cmpFactories, IFreePageManager freePageManager,
-            ITreeIndexFrameFactory interiorFrameFactory, ITreeIndexFrameFactory leafFrameFactory) {
+    public BTree(IBufferCache bufferCache, int fieldCount, IBinaryComparatorFactory[] cmpFactories,
+            IFreePageManager freePageManager, ITreeIndexFrameFactory interiorFrameFactory,
+            ITreeIndexFrameFactory leafFrameFactory) {
         this.bufferCache = bufferCache;
-        this.opCallback = opCallback;
         this.fieldCount = fieldCount;
         this.cmpFactories = cmpFactories;
         this.interiorFrameFactory = interiorFrameFactory;
@@ -406,13 +405,10 @@
         boolean restartOp = false;
         ITupleReference beforeTuple = ctx.leafFrame.getUpsertBeforeTuple(tuple, targetTupleIndex);
         if (beforeTuple == null) {
-            opCallback.pre(null);
             restartOp = insertLeaf(tuple, targetTupleIndex, pageId, ctx);
         } else {
-            opCallback.pre(beforeTuple);
             restartOp = updateLeaf(tuple, targetTupleIndex, pageId, ctx);
         }
-        opCallback.post(tuple);
         return restartOp;
     }
 
@@ -1011,7 +1007,7 @@
     }
 
     @Override
-    public ITreeIndexAccessor createAccessor() {
+    public ITreeIndexAccessor createAccessor(IModificationOperationCallback modificationCallback, ISearchOperationCallback searchCallback) {
         return new BTreeAccessor(this);
     }
 
diff --git a/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/util/BTreeUtils.java b/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/util/BTreeUtils.java
index 57e3a96..48b5b38 100644
--- a/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/util/BTreeUtils.java
+++ b/hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/util/BTreeUtils.java
@@ -11,7 +11,6 @@
 import edu.uci.ics.hyracks.storage.am.btree.frames.BTreeNSMLeafFrameFactory;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTree;
 import edu.uci.ics.hyracks.storage.am.common.api.IFreePageManager;
-import edu.uci.ics.hyracks.storage.am.common.api.IOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexFrameFactory;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexMetaDataFrameFactory;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexTupleWriterFactory;
@@ -22,13 +21,13 @@
 import edu.uci.ics.hyracks.storage.common.buffercache.IBufferCache;
 
 public class BTreeUtils {
-    public static BTree createBTree(IBufferCache bufferCache, IOperationCallback opCallback, ITypeTraits[] typeTraits, IBinaryComparatorFactory[] cmpFactories, BTreeLeafFrameType leafType) throws BTreeException {
+    public static BTree createBTree(IBufferCache bufferCache, ITypeTraits[] typeTraits, IBinaryComparatorFactory[] cmpFactories, BTreeLeafFrameType leafType) throws BTreeException {
         TypeAwareTupleWriterFactory tupleWriterFactory = new TypeAwareTupleWriterFactory(typeTraits);
         ITreeIndexFrameFactory leafFrameFactory = getLeafFrameFactory(tupleWriterFactory, leafType);
         ITreeIndexFrameFactory interiorFrameFactory = new BTreeNSMInteriorFrameFactory(tupleWriterFactory);
         ITreeIndexMetaDataFrameFactory metaFrameFactory = new LIFOMetaDataFrameFactory();
         IFreePageManager freePageManager = new LinkedListFreePageManager(bufferCache, 0, metaFrameFactory);
-        BTree btree = new BTree(bufferCache, opCallback, typeTraits.length, cmpFactories, freePageManager, interiorFrameFactory, leafFrameFactory);
+        BTree btree = new BTree(bufferCache, typeTraits.length, cmpFactories, freePageManager, interiorFrameFactory, leafFrameFactory);
         return btree;
     }
     
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/IModificationOperationCallback.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/IModificationOperationCallback.java
new file mode 100644
index 0000000..0e2ff20
--- /dev/null
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/IModificationOperationCallback.java
@@ -0,0 +1,11 @@
+package edu.uci.ics.hyracks.storage.am.common.api;
+
+import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
+
+public interface IModificationOperationCallback {
+    public void before(ITupleReference tuple);
+
+    public void commence(ITupleReference tuple);
+
+    public void found(ITupleReference tuple);
+}
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/IOperationCallback.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/IOperationCallback.java
deleted file mode 100644
index 9e66b43..0000000
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/IOperationCallback.java
+++ /dev/null
@@ -1,9 +0,0 @@
-package edu.uci.ics.hyracks.storage.am.common.api;
-
-import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
-
-public interface IOperationCallback {
-    public void pre(ITupleReference tuple);
-
-    public void post(ITupleReference tuple);
-}
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/IOperationCallbackProvider.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/IOperationCallbackProvider.java
index 974ef1a..98e297f 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/IOperationCallbackProvider.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/IOperationCallbackProvider.java
@@ -3,5 +3,7 @@
 import java.io.Serializable;
 
 public interface IOperationCallbackProvider extends Serializable {
-    public IOperationCallback getOperationCallback();
+    public IModificationOperationCallback getModificationOperationCallback();
+
+    public ISearchOperationCallback getSearchOperationCallback();
 }
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/ISearchOperationCallback.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/ISearchOperationCallback.java
new file mode 100644
index 0000000..ad4e001
--- /dev/null
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/api/ISearchOperationCallback.java
@@ -0,0 +1,11 @@
+package edu.uci.ics.hyracks.storage.am.common.api;
+
+import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
+
+public interface ISearchOperationCallback {
+    public void before(ITupleReference tuple);
+
+    public boolean proceed(ITupleReference tuple);
+
+    public void reconcile(ITupleReference tuple);
+}
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/IIndex.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/IIndex.java
index 64cbd58..06efe6b 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/IIndex.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/IIndex.java
@@ -19,6 +19,8 @@
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexBulkLoadContext;
+import edu.uci.ics.hyracks.storage.am.common.api.IModificationOperationCallback;
+import edu.uci.ics.hyracks.storage.am.common.api.ISearchOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
 import edu.uci.ics.hyracks.storage.am.common.api.IndexType;
 import edu.uci.ics.hyracks.storage.common.buffercache.IBufferCache;
@@ -60,8 +62,11 @@
      * on the same IIndex
      * 
      * @returns IIndexAccessor An accessor for this tree.
+     * @param modificationCallback TODO
+     * @param searchCallback TODO
      */
-    public IIndexAccessor createAccessor();
+    public IIndexAccessor createAccessor(IModificationOperationCallback modificationCallback,
+            ISearchOperationCallback searchCallback);
 
     /**
      * Prepares the index for bulk loading, returning a bulk load context. The
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/TreeIndexDiskOrderScanOperatorNodePushable.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/TreeIndexDiskOrderScanOperatorNodePushable.java
index d02a570..eb47db7 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/TreeIndexDiskOrderScanOperatorNodePushable.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/TreeIndexDiskOrderScanOperatorNodePushable.java
@@ -24,6 +24,7 @@
 import edu.uci.ics.hyracks.dataflow.common.comm.util.FrameUtils;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
 import edu.uci.ics.hyracks.dataflow.std.base.AbstractUnaryOutputSourceOperatorNodePushable;
+import edu.uci.ics.hyracks.storage.am.common.api.IOperationCallbackProvider;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexCursor;
@@ -32,11 +33,13 @@
 public class TreeIndexDiskOrderScanOperatorNodePushable extends AbstractUnaryOutputSourceOperatorNodePushable {
     private final TreeIndexDataflowHelper treeIndexHelper;
     private ITreeIndex treeIndex;
+    private final IOperationCallbackProvider callbackProvider;
 
     public TreeIndexDiskOrderScanOperatorNodePushable(AbstractTreeIndexOperatorDescriptor opDesc,
             IHyracksTaskContext ctx, int partition) {
         treeIndexHelper = (TreeIndexDataflowHelper) opDesc.getIndexDataflowHelperFactory().createIndexDataflowHelper(
                 opDesc, ctx, partition);
+        this.callbackProvider = opDesc.getOpCallbackProvider();
     }
 
     @Override
@@ -46,7 +49,8 @@
             treeIndex = (ITreeIndex) treeIndexHelper.getIndex();
             ITreeIndexFrame cursorFrame = treeIndex.getLeafFrameFactory().createFrame();
             ITreeIndexCursor cursor = treeIndexHelper.createDiskOrderScanCursor(cursorFrame);
-            ITreeIndexAccessor indexAccessor = (ITreeIndexAccessor) treeIndex.createAccessor();
+            ITreeIndexAccessor indexAccessor = (ITreeIndexAccessor) treeIndex.createAccessor(
+                    callbackProvider.getModificationOperationCallback(), callbackProvider.getSearchOperationCallback());
             writer.open();
             try {
                 indexAccessor.diskOrderScan(cursor);
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/TreeIndexInsertUpdateDeleteOperatorNodePushable.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/TreeIndexInsertUpdateDeleteOperatorNodePushable.java
index e432456..a57cef7 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/TreeIndexInsertUpdateDeleteOperatorNodePushable.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/TreeIndexInsertUpdateDeleteOperatorNodePushable.java
@@ -25,6 +25,7 @@
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.FrameTupleReference;
 import edu.uci.ics.hyracks.dataflow.std.base.AbstractUnaryInputUnaryOutputOperatorNodePushable;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexAccessor;
+import edu.uci.ics.hyracks.storage.am.common.api.IOperationCallbackProvider;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.api.ITupleFilter;
 import edu.uci.ics.hyracks.storage.am.common.api.ITupleFilterFactory;
@@ -40,7 +41,8 @@
     private ByteBuffer writeBuffer;
     private IIndexAccessor indexAccessor;
     private ITupleFilter tupleFilter;
-    
+    private final IOperationCallbackProvider callbackProvider;
+
     public TreeIndexInsertUpdateDeleteOperatorNodePushable(AbstractTreeIndexOperatorDescriptor opDesc,
             IHyracksTaskContext ctx, int partition, int[] fieldPermutation,
             IRecordDescriptorProvider recordDescProvider, IndexOp op) {
@@ -48,6 +50,7 @@
                 opDesc, ctx, partition);
         this.recordDescProvider = recordDescProvider;
         this.op = op;
+        this.callbackProvider = opDesc.getOpCallbackProvider();
         tuple.setFieldPermutation(fieldPermutation);
     }
 
@@ -62,11 +65,12 @@
         try {
             treeIndexHelper.init(false);
             ITreeIndex treeIndex = (ITreeIndex) treeIndexHelper.getIndex();
-            indexAccessor = treeIndex.createAccessor();
+            indexAccessor = treeIndex.createAccessor(callbackProvider.getModificationOperationCallback(),
+                    callbackProvider.getSearchOperationCallback());
             ITupleFilterFactory tupleFilterFactory = opDesc.getTupleFilterFactory();
             if (tupleFilterFactory != null) {
-            	tupleFilter = tupleFilterFactory.createTupleFilter();
-            	frameTuple = new FrameTupleReference();
+                tupleFilter = tupleFilterFactory.createTupleFilter();
+                frameTuple = new FrameTupleReference();
             }
         } catch (Exception e) {
             // cleanup in case of failure
@@ -79,15 +83,15 @@
     public void nextFrame(ByteBuffer buffer) throws HyracksDataException {
         accessor.reset(buffer);
         int tupleCount = accessor.getTupleCount();
-        for (int i = 0; i < tupleCount; i++) {            
+        for (int i = 0; i < tupleCount; i++) {
             try {
-            	if (tupleFilter != null) {
+                if (tupleFilter != null) {
                     frameTuple.reset(accessor, i);
                     if (!tupleFilter.accept(frameTuple)) {
                         continue;
                     }
                 }
-            	tuple.reset(accessor, i);
+                tuple.reset(accessor, i);
                 switch (op) {
                     case INSERT: {
                         indexAccessor.insert(tuple);
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/TreeIndexSearchOperatorNodePushable.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/TreeIndexSearchOperatorNodePushable.java
index 0bd970a..c0217c3 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/TreeIndexSearchOperatorNodePushable.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/TreeIndexSearchOperatorNodePushable.java
@@ -29,6 +29,7 @@
 import edu.uci.ics.hyracks.dataflow.std.base.AbstractUnaryInputUnaryOutputOperatorNodePushable;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexCursor;
+import edu.uci.ics.hyracks.storage.am.common.api.IOperationCallbackProvider;
 import edu.uci.ics.hyracks.storage.am.common.api.ISearchPredicate;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexFrame;
@@ -50,11 +51,14 @@
 
     protected RecordDescriptor recDesc;
 
+    private final IOperationCallbackProvider callbackProvider;
+
     public TreeIndexSearchOperatorNodePushable(AbstractTreeIndexOperatorDescriptor opDesc, IHyracksTaskContext ctx,
             int partition, IRecordDescriptorProvider recordDescProvider) {
         treeIndexHelper = (TreeIndexDataflowHelper) opDesc.getIndexDataflowHelperFactory().createIndexDataflowHelper(
                 opDesc, ctx, partition);
         this.recDesc = recordDescProvider.getInputRecordDescriptor(opDesc.getOperatorId(), 0);
+        this.callbackProvider = opDesc.getOpCallbackProvider();
     }
 
     protected abstract ISearchPredicate createSearchPredicate();
@@ -79,7 +83,8 @@
             dos = tb.getDataOutput();
             appender = new FrameTupleAppender(treeIndexHelper.getHyracksTaskContext().getFrameSize());
             appender.reset(writeBuffer, true);
-            indexAccessor = treeIndex.createAccessor();
+            indexAccessor = treeIndex.createAccessor(callbackProvider.getModificationOperationCallback(),
+                    callbackProvider.getSearchOperationCallback());
             cursor = createCursor();
         } catch (Exception e) {
             treeIndexHelper.deinit();
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/impls/NoOpOperationCallback.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/impls/NoOpOperationCallback.java
index 828dd81..36d2585 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/impls/NoOpOperationCallback.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/impls/NoOpOperationCallback.java
@@ -16,26 +16,39 @@
 package edu.uci.ics.hyracks.storage.am.common.impls;
 
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
-import edu.uci.ics.hyracks.storage.am.common.api.IOperationCallback;
+import edu.uci.ics.hyracks.storage.am.common.api.IModificationOperationCallback;
+import edu.uci.ics.hyracks.storage.am.common.api.ISearchOperationCallback;
 
 /**
  * Dummy operation callback that simply does nothing. Mainly, intended to be
  * used in non-transaction access method testing.
  */
-public class NoOpOperationCallback implements IOperationCallback {
+public enum NoOpOperationCallback implements IModificationOperationCallback, ISearchOperationCallback {
+    INSTANCE;
 
-    public static IOperationCallback INSTANCE = new NoOpOperationCallback();
-    
-    private NoOpOperationCallback() {
-    }
-    
     @Override
-    public void pre(ITupleReference tuple) {
+    public boolean proceed(ITupleReference tuple) {
+        // Always proceed.
+        return true;
+    }
+
+    @Override
+    public void reconcile(ITupleReference tuple) {
         // Do nothing.
     }
 
     @Override
-    public void post(ITupleReference tuple) {
-        // Do nothing.
+    public void before(ITupleReference tuple) {
+        // Do nothing.        
+    }
+
+    @Override
+    public void commence(ITupleReference tuple) {
+        // Do nothing.        
+    }
+
+    @Override
+    public void found(ITupleReference tuple) {
+        // Do nothing.        
     }
 }
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/impls/NoOpOperationCallbackProvider.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/impls/NoOpOperationCallbackProvider.java
index 55dfb74..bda1f69 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/impls/NoOpOperationCallbackProvider.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/impls/NoOpOperationCallbackProvider.java
@@ -1,7 +1,8 @@
 package edu.uci.ics.hyracks.storage.am.common.impls;
 
-import edu.uci.ics.hyracks.storage.am.common.api.IOperationCallback;
+import edu.uci.ics.hyracks.storage.am.common.api.IModificationOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.api.IOperationCallbackProvider;
+import edu.uci.ics.hyracks.storage.am.common.api.ISearchOperationCallback;
 
 /**
  * Dummy NoOp callback provider used primarily for testing. Always returns the 
@@ -13,7 +14,12 @@
     INSTANCE;
 
     @Override
-    public IOperationCallback getOperationCallback() {
+    public IModificationOperationCallback getModificationOperationCallback() {
+        return NoOpOperationCallback.INSTANCE;
+    }
+
+    @Override
+    public ISearchOperationCallback getSearchOperationCallback() {
         return NoOpOperationCallback.INSTANCE;
     }
 }
diff --git a/hyracks-storage-am-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/invertedindex/dataflow/InvertedIndexSearchOperatorNodePushable.java b/hyracks-storage-am-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/invertedindex/dataflow/InvertedIndexSearchOperatorNodePushable.java
index 8536a07..4b506aa 100644
--- a/hyracks-storage-am-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/invertedindex/dataflow/InvertedIndexSearchOperatorNodePushable.java
+++ b/hyracks-storage-am-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/invertedindex/dataflow/InvertedIndexSearchOperatorNodePushable.java
@@ -32,6 +32,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexCursor;
 import edu.uci.ics.hyracks.storage.am.common.dataflow.TreeIndexDataflowHelper;
+import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.invertedindex.api.IInvertedIndexSearchModifier;
 import edu.uci.ics.hyracks.storage.am.invertedindex.impls.InvertedIndex;
 import edu.uci.ics.hyracks.storage.am.invertedindex.impls.InvertedIndexSearchPredicate;
@@ -106,7 +107,7 @@
         appender = new FrameTupleAppender(btreeDataflowHelper.getHyracksTaskContext().getFrameSize());
         appender.reset(writeBuffer, true);
 
-        indexAccessor = invIndex.createAccessor();
+        indexAccessor = invIndex.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
         resultCursor = indexAccessor.createSearchCursor();
         writer.open();
     }
diff --git a/hyracks-storage-am-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/invertedindex/impls/InvertedIndex.java b/hyracks-storage-am-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/invertedindex/impls/InvertedIndex.java
index 722cacc..6d94f77 100644
--- a/hyracks-storage-am-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/invertedindex/impls/InvertedIndex.java
+++ b/hyracks-storage-am-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/invertedindex/impls/InvertedIndex.java
@@ -32,6 +32,8 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexBulkLoadContext;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexCursor;
+import edu.uci.ics.hyracks.storage.am.common.api.IModificationOperationCallback;
+import edu.uci.ics.hyracks.storage.am.common.api.ISearchOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.api.ISearchPredicate;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexCursor;
@@ -340,7 +342,7 @@
     }
     
     @Override
-    public IIndexAccessor createAccessor() {
+    public IIndexAccessor createAccessor(IModificationOperationCallback modificationCallback, ISearchOperationCallback searchCallback) {
         return new InvertedIndexAccessor(this);
     }
 
diff --git a/hyracks-storage-am-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/invertedindex/impls/TOccurrenceSearcher.java b/hyracks-storage-am-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/invertedindex/impls/TOccurrenceSearcher.java
index 3270216..bf4857e 100644
--- a/hyracks-storage-am-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/invertedindex/impls/TOccurrenceSearcher.java
+++ b/hyracks-storage-am-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/invertedindex/impls/TOccurrenceSearcher.java
@@ -42,6 +42,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexCursor;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexFrame;
 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.common.ophelpers.MultiComparator;
 import edu.uci.ics.hyracks.storage.am.invertedindex.api.IInvertedIndexSearchModifier;
 import edu.uci.ics.hyracks.storage.am.invertedindex.api.IInvertedIndexSearcher;
@@ -129,7 +130,8 @@
         queryTokenAppender = new FrameTupleAppender(ctx.getFrameSize());
         queryTokenFrame = ctx.allocateFrame();
 
-        btreeAccessor = invIndex.getBTree().createAccessor();
+        btreeAccessor = invIndex.getBTree().createAccessor(NoOpOperationCallback.INSTANCE,
+                NoOpOperationCallback.INSTANCE);
         currentNumResults = 0;
     }
 
@@ -143,12 +145,13 @@
         currentNumResults = 0;
     }
 
-    public void search(InvertedIndexSearchCursor resultCursor, InvertedIndexSearchPredicate searchPred) throws HyracksDataException, IndexException {
+    public void search(InvertedIndexSearchCursor resultCursor, InvertedIndexSearchPredicate searchPred)
+            throws HyracksDataException, IndexException {
         ITupleReference queryTuple = searchPred.getQueryTuple();
         int queryFieldIndex = searchPred.getQueryFieldIndex();
         IInvertedIndexSearchModifier searchModifier = searchPred.getSearchModifier();
-        
-        queryTokenAppender.reset(queryTokenFrame, true);                
+
+        queryTokenAppender.reset(queryTokenFrame, true);
         queryTokenizer.reset(queryTuple.getFieldData(queryFieldIndex), queryTuple.getFieldStart(queryFieldIndex),
                 queryTuple.getFieldLength(queryFieldIndex));
 
@@ -216,7 +219,8 @@
         return maxPrevBufIdx;
     }
 
-    protected int mergeSuffixLists(int numPrefixTokens, int numQueryTokens, int maxPrevBufIdx) throws HyracksDataException {
+    protected int mergeSuffixLists(int numPrefixTokens, int numQueryTokens, int maxPrevBufIdx)
+            throws HyracksDataException {
         for (int i = numPrefixTokens; i < numQueryTokens; i++) {
             swap = prevResultBuffers;
             prevResultBuffers = newResultBuffers;
diff --git a/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/dataflow/LSMBTreeDataflowHelper.java b/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/dataflow/LSMBTreeDataflowHelper.java
index d748af4..ded4570 100644
--- a/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/dataflow/LSMBTreeDataflowHelper.java
+++ b/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/dataflow/LSMBTreeDataflowHelper.java
@@ -66,10 +66,9 @@
             file.delete();
         }
         InMemoryFreePageManager memFreePageManager = new InMemoryFreePageManager(memNumPages, metaDataFrameFactory);
-        return LSMBTreeUtils.createLSMTree(memBufferCache, opDesc.getOpCallbackProvider().getOperationCallback(),
-                memFreePageManager, ctx.getIOManager(), file.getFile().getPath(), opDesc.getStorageManager()
+        return LSMBTreeUtils.createLSMTree(memBufferCache, memFreePageManager,
+                ctx.getIOManager(), file.getFile().getPath(), opDesc.getStorageManager()
                         .getBufferCache(ctx), opDesc.getStorageManager().getFileMapProvider(ctx), treeOpDesc
-                        .getTreeIndexTypeTraits(), treeOpDesc.getTreeIndexComparatorFactories(), flushPolicy,
-                mergePolicy);
+                        .getTreeIndexTypeTraits(), treeOpDesc.getTreeIndexComparatorFactories(), flushPolicy, mergePolicy);
     }
 }
diff --git a/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTree.java b/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTree.java
index 7d46a37..547cf2d 100644
--- a/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTree.java
+++ b/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTree.java
@@ -33,7 +33,8 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexBulkLoadContext;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexCursor;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexOpContext;
-import edu.uci.ics.hyracks.storage.am.common.api.IOperationCallback;
+import edu.uci.ics.hyracks.storage.am.common.api.IModificationOperationCallback;
+import edu.uci.ics.hyracks.storage.am.common.api.ISearchOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.api.ISearchPredicate;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexAccessor;
@@ -42,6 +43,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
 import edu.uci.ics.hyracks.storage.am.common.api.IndexType;
 import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
+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.common.api.ILSMComponentFinalizer;
@@ -87,14 +89,14 @@
 
     private boolean isOpen = false;
 
-    public LSMBTree(IBufferCache memBufferCache, IOperationCallback memOpCallback,
-            InMemoryFreePageManager memFreePageManager, ITreeIndexFrameFactory interiorFrameFactory,
-            ITreeIndexFrameFactory insertLeafFrameFactory, ITreeIndexFrameFactory deleteLeafFrameFactory,
-            ILSMFileManager fileNameManager, BTreeFactory diskBTreeFactory, BTreeFactory bulkLoadBTreeFactory,
-            IFileMapProvider diskFileMapProvider, int fieldCount, IBinaryComparatorFactory[] cmpFactories,
-            ILSMFlushPolicy flushPolicy, ILSMMergePolicy mergePolicy) {
-        memBTree = new BTree(memBufferCache, memOpCallback, fieldCount, cmpFactories, memFreePageManager,
-                interiorFrameFactory, insertLeafFrameFactory);
+    public LSMBTree(IBufferCache memBufferCache, InMemoryFreePageManager memFreePageManager,
+            ITreeIndexFrameFactory interiorFrameFactory, ITreeIndexFrameFactory insertLeafFrameFactory,
+            ITreeIndexFrameFactory deleteLeafFrameFactory, ILSMFileManager fileNameManager,
+            BTreeFactory diskBTreeFactory, BTreeFactory bulkLoadBTreeFactory, IFileMapProvider diskFileMapProvider,
+            int fieldCount, IBinaryComparatorFactory[] cmpFactories, ILSMFlushPolicy flushPolicy,
+            ILSMMergePolicy mergePolicy) {
+        memBTree = new BTree(memBufferCache, fieldCount, cmpFactories, memFreePageManager, interiorFrameFactory,
+                insertLeafFrameFactory);
         this.memFreePageManager = memFreePageManager;
         this.insertLeafFrameFactory = insertLeafFrameFactory;
         this.deleteLeafFrameFactory = deleteLeafFrameFactory;
@@ -179,7 +181,8 @@
     public ITreeIndex flush() throws HyracksDataException, IndexException {
         // Bulk load a new on-disk BTree from the in-memory BTree.        
         RangePredicate nullPred = new RangePredicate(null, null, true, true, null, null);
-        ITreeIndexAccessor memBTreeAccessor = memBTree.createAccessor();
+        ITreeIndexAccessor memBTreeAccessor = memBTree.createAccessor(NoOpOperationCallback.INSTANCE,
+                NoOpOperationCallback.INSTANCE);
         IIndexCursor scanCursor = memBTreeAccessor.createSearchCursor();
         memBTreeAccessor.search(scanCursor, nullPred);
         BTree diskBTree = createFlushTarget();
@@ -274,7 +277,8 @@
         ListIterator<Object> diskBTreesIter = diskComponents.listIterator();
         while (diskBTreesIter.hasNext()) {
             BTree diskBTree = (BTree) diskBTreesIter.next();
-            diskBTreeAccessors[diskBTreeIx] = diskBTree.createAccessor();
+            diskBTreeAccessors[diskBTreeIx] = diskBTree.createAccessor(NoOpOperationCallback.INSTANCE,
+                    NoOpOperationCallback.INSTANCE);
             diskBTreeAccessors[diskBTreeIx].search(lsmTreeCursor.getCursor(cursorIx), pred);
             cursorIx++;
             diskBTreeIx++;
@@ -428,7 +432,8 @@
     }
 
     @Override
-    public IIndexAccessor createAccessor() {
+    public IIndexAccessor createAccessor(IModificationOperationCallback modificationCallback,
+            ISearchOperationCallback searchCallback) {
         return new LSMBTreeIndexAccessor(lsmHarness, createOpContext());
     }
 
diff --git a/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreeOpContext.java b/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreeOpContext.java
index 4f096ef..d94dc52 100644
--- a/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreeOpContext.java
+++ b/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreeOpContext.java
@@ -20,87 +20,89 @@
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTreeOpContext;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexOpContext;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexFrameFactory;
+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;
 
 public final class LSMBTreeOpContext implements IIndexOpContext {
-    
-	public ITreeIndexFrameFactory insertLeafFrameFactory;
-	public ITreeIndexFrameFactory deleteLeafFrameFactory;
-	public IBTreeLeafFrame insertLeafFrame;
-	public IBTreeLeafFrame deleteLeafFrame;
-	public final BTree memBTree;
-	public BTree.BTreeAccessor memBTreeAccessor;
-	public BTreeOpContext memBTreeOpCtx;
-	public IndexOp op;
-	public final MultiComparator cmp;
-	
+
+    public ITreeIndexFrameFactory insertLeafFrameFactory;
+    public ITreeIndexFrameFactory deleteLeafFrameFactory;
+    public IBTreeLeafFrame insertLeafFrame;
+    public IBTreeLeafFrame deleteLeafFrame;
+    public final BTree memBTree;
+    public BTree.BTreeAccessor memBTreeAccessor;
+    public BTreeOpContext memBTreeOpCtx;
+    public IndexOp op;
+    public final MultiComparator cmp;
+
     public LSMBTreeOpContext(BTree memBTree, ITreeIndexFrameFactory insertLeafFrameFactory,
             ITreeIndexFrameFactory deleteLeafFrameFactory) {
-		this.cmp = MultiComparator.create(memBTree.getComparatorFactories());
+        this.cmp = MultiComparator.create(memBTree.getComparatorFactories());
         this.memBTree = memBTree;
-		this.insertLeafFrameFactory = insertLeafFrameFactory;
-		this.deleteLeafFrameFactory = deleteLeafFrameFactory;
-		this.insertLeafFrame = (IBTreeLeafFrame) insertLeafFrameFactory.createFrame();
-		this.deleteLeafFrame = (IBTreeLeafFrame) deleteLeafFrameFactory.createFrame();
-		if (insertLeafFrame != null) {
-			insertLeafFrame.setMultiComparator(cmp);
+        this.insertLeafFrameFactory = insertLeafFrameFactory;
+        this.deleteLeafFrameFactory = deleteLeafFrameFactory;
+        this.insertLeafFrame = (IBTreeLeafFrame) insertLeafFrameFactory.createFrame();
+        this.deleteLeafFrame = (IBTreeLeafFrame) deleteLeafFrameFactory.createFrame();
+        if (insertLeafFrame != null) {
+            insertLeafFrame.setMultiComparator(cmp);
         }
         if (deleteLeafFrame != null) {
-        	deleteLeafFrame.setMultiComparator(cmp);
+            deleteLeafFrame.setMultiComparator(cmp);
         }
-	}
+    }
 
     @Override
     public void reset(IndexOp newOp) {
-    	this.op = newOp;
+        this.op = newOp;
         switch (newOp) {
-    	    case SEARCH:
-    	        setMemBTreeAccessor();
-    	        break;
-    	        
-    	    case DISKORDERSCAN:
-    	    case UPDATE:
+            case SEARCH:
+                setMemBTreeAccessor();
+                break;
+
+            case DISKORDERSCAN:
+            case UPDATE:
                 // Attention: It is important to leave the leafFrame and
                 // leafFrameFactory of the memBTree as is when doing an update.
                 // Update will only be set if a previous attempt to delete or
                 // insert failed, so we must preserve the semantics of the
                 // previously requested operation.
-    	        return;
-    	        
-    	    case INSERT:    	    
-    	        setInsertMode();
-    	        break;
-    	        
-    	    case DELETE:
+                return;
+
+            case INSERT:
+                setInsertMode();
+                break;
+
+            case DELETE:
                 setDeleteMode();
                 break;
-    	}
+        }
     }
-	
+
     private void setMemBTreeAccessor() {
         if (memBTreeAccessor == null) {
-            memBTreeAccessor = (BTree.BTreeAccessor) memBTree.createAccessor();
+            memBTreeAccessor = (BTree.BTreeAccessor) memBTree.createAccessor(NoOpOperationCallback.INSTANCE,
+                    NoOpOperationCallback.INSTANCE);
             memBTreeOpCtx = memBTreeAccessor.getOpContext();
         }
     }
-    
-	public void setInsertMode() {
-	    setMemBTreeAccessor();
-	    memBTreeOpCtx.leafFrame = insertLeafFrame;
-	    memBTreeOpCtx.leafFrameFactory = insertLeafFrameFactory;
-	}
-	
-	public void setDeleteMode() {
-	    setMemBTreeAccessor();
-	    memBTreeOpCtx.leafFrame = deleteLeafFrame;
+
+    public void setInsertMode() {
+        setMemBTreeAccessor();
+        memBTreeOpCtx.leafFrame = insertLeafFrame;
+        memBTreeOpCtx.leafFrameFactory = insertLeafFrameFactory;
+    }
+
+    public void setDeleteMode() {
+        setMemBTreeAccessor();
+        memBTreeOpCtx.leafFrame = deleteLeafFrame;
         memBTreeOpCtx.leafFrameFactory = deleteLeafFrameFactory;
-	}
+    }
 
     @Override
     public void reset() {
     }
-    
+
     public IndexOp getIndexOp() {
         return op;
     }
diff --git a/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeUtils.java b/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeUtils.java
index 94512a5..f91912f 100644
--- a/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeUtils.java
+++ b/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeUtils.java
@@ -20,12 +20,10 @@
 import edu.uci.ics.hyracks.api.io.IIOManager;
 import edu.uci.ics.hyracks.storage.am.btree.frames.BTreeNSMInteriorFrameFactory;
 import edu.uci.ics.hyracks.storage.am.btree.frames.BTreeNSMLeafFrameFactory;
-import edu.uci.ics.hyracks.storage.am.common.api.IOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexFrameFactory;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexMetaDataFrameFactory;
 import edu.uci.ics.hyracks.storage.am.common.frames.LIFOMetaDataFrameFactory;
 import edu.uci.ics.hyracks.storage.am.common.freepage.LinkedListFreePageManagerFactory;
-import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.lsm.btree.impls.LSMBTree;
 import edu.uci.ics.hyracks.storage.am.lsm.btree.tuples.LSMBTreeCopyTupleWriterFactory;
 import edu.uci.ics.hyracks.storage.am.lsm.btree.tuples.LSMBTreeTupleWriterFactory;
@@ -40,10 +38,10 @@
 import edu.uci.ics.hyracks.storage.common.file.IFileMapProvider;
 
 public class LSMBTreeUtils {
-    public static LSMBTree createLSMTree(InMemoryBufferCache memBufferCache, IOperationCallback memOpCallback,
-            InMemoryFreePageManager memFreePageManager, IIOManager ioManager, String onDiskDir,
-            IBufferCache diskBufferCache, IFileMapProvider diskFileMapProvider, ITypeTraits[] typeTraits,
-            IBinaryComparatorFactory[] cmpFactories, ILSMFlushPolicy flushPolicy, ILSMMergePolicy mergePolicy) {
+    public static LSMBTree createLSMTree(InMemoryBufferCache memBufferCache, InMemoryFreePageManager memFreePageManager,
+            IIOManager ioManager, String onDiskDir, IBufferCache diskBufferCache,
+            IFileMapProvider diskFileMapProvider, ITypeTraits[] typeTraits, IBinaryComparatorFactory[] cmpFactories,
+            ILSMFlushPolicy flushPolicy, ILSMMergePolicy mergePolicy) {
         LSMBTreeTupleWriterFactory insertTupleWriterFactory = new LSMBTreeTupleWriterFactory(typeTraits,
                 cmpFactories.length, false);
         LSMBTreeTupleWriterFactory deleteTupleWriterFactory = new LSMBTreeTupleWriterFactory(typeTraits,
@@ -57,15 +55,14 @@
         ITreeIndexMetaDataFrameFactory metaFrameFactory = new LIFOMetaDataFrameFactory();
         LinkedListFreePageManagerFactory freePageManagerFactory = new LinkedListFreePageManagerFactory(diskBufferCache,
                 metaFrameFactory);
-        BTreeFactory diskBTreeFactory = new BTreeFactory(diskBufferCache, NoOpOperationCallback.INSTANCE,
-                freePageManagerFactory, cmpFactories, typeTraits.length, interiorFrameFactory,
-                copyTupleLeafFrameFactory);
-        BTreeFactory bulkLoadBTreeFactory = new BTreeFactory(diskBufferCache, NoOpOperationCallback.INSTANCE,
-                freePageManagerFactory, cmpFactories, typeTraits.length, interiorFrameFactory, insertLeafFrameFactory);
+        BTreeFactory diskBTreeFactory = new BTreeFactory(diskBufferCache, freePageManagerFactory,
+                cmpFactories, typeTraits.length, interiorFrameFactory, copyTupleLeafFrameFactory);
+        BTreeFactory bulkLoadBTreeFactory = new BTreeFactory(diskBufferCache, freePageManagerFactory,
+                cmpFactories, typeTraits.length, interiorFrameFactory, insertLeafFrameFactory);
         ILSMFileManager fileNameManager = new LSMTreeFileManager(ioManager, diskFileMapProvider, onDiskDir);
-        LSMBTree lsmTree = new LSMBTree(memBufferCache, memOpCallback, memFreePageManager, interiorFrameFactory,
-                insertLeafFrameFactory, deleteLeafFrameFactory, fileNameManager, diskBTreeFactory,
-                bulkLoadBTreeFactory, diskFileMapProvider, typeTraits.length, cmpFactories, flushPolicy, mergePolicy);
+        LSMBTree lsmTree = new LSMBTree(memBufferCache, memFreePageManager, interiorFrameFactory, insertLeafFrameFactory,
+                deleteLeafFrameFactory, fileNameManager, diskBTreeFactory, bulkLoadBTreeFactory,
+                diskFileMapProvider, typeTraits.length, cmpFactories, flushPolicy, mergePolicy);
         return lsmTree;
     }
 }
diff --git a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/BTreeFactory.java b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/BTreeFactory.java
index 0578976..b51b84b 100644
--- a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/BTreeFactory.java
+++ b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/BTreeFactory.java
@@ -17,25 +17,21 @@
 
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTree;
-import edu.uci.ics.hyracks.storage.am.common.api.IOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexFrameFactory;
 import edu.uci.ics.hyracks.storage.am.common.freepage.LinkedListFreePageManagerFactory;
 import edu.uci.ics.hyracks.storage.common.buffercache.IBufferCache;
 
 public class BTreeFactory extends TreeFactory<BTree> {
 
-    private final IOperationCallback opCallback;
-    
-    public BTreeFactory(IBufferCache bufferCache, IOperationCallback opCallback, LinkedListFreePageManagerFactory freePageManagerFactory,
+    public BTreeFactory(IBufferCache bufferCache, LinkedListFreePageManagerFactory freePageManagerFactory,
             IBinaryComparatorFactory[] cmpFactories, int fieldCount, ITreeIndexFrameFactory interiorFrameFactory,
             ITreeIndexFrameFactory leafFrameFactory) {
         super(bufferCache, freePageManagerFactory, cmpFactories, fieldCount, interiorFrameFactory, leafFrameFactory);
-        this.opCallback = opCallback;
     }
 
     @Override
     public BTree createIndexInstance() {
-        return new BTree(bufferCache, opCallback, fieldCount, cmpFactories, freePageManagerFactory.createFreePageManager(),
+        return new BTree(bufferCache, fieldCount, cmpFactories, freePageManagerFactory.createFreePageManager(),
                 interiorFrameFactory, leafFrameFactory);
     }
 
diff --git a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/SequentialScheduler.java b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/SequentialScheduler.java
index 8be892b..90ef3e3 100644
--- a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/SequentialScheduler.java
+++ b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/SequentialScheduler.java
@@ -5,6 +5,7 @@
 
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 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.ILSMIOScheduler;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndex;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexAccessor;
@@ -21,7 +22,8 @@
             @Override
             public void run() {
                 try {
-                    ((ILSMIndexAccessor) index.createAccessor()).flush();
+                    ((ILSMIndexAccessor) index.createAccessor(NoOpOperationCallback.INSTANCE,
+                            NoOpOperationCallback.INSTANCE)).flush();
                 } catch (HyracksDataException e) {
                     e.printStackTrace();
                 } catch (IndexException e) {
@@ -38,7 +40,8 @@
             @Override
             public void run() {
                 try {
-                    ((ILSMIndexAccessor) index.createAccessor()).merge();
+                    ((ILSMIndexAccessor) index.createAccessor(NoOpOperationCallback.INSTANCE,
+                            NoOpOperationCallback.INSTANCE)).merge();
                 } catch (LSMMergeInProgressException e) {
                     // Ignore!
                 } catch (HyracksDataException e) {
diff --git a/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTree.java b/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTree.java
index 6ae80ae..2bea518 100644
--- a/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTree.java
+++ b/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTree.java
@@ -34,6 +34,8 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexBulkLoadContext;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexCursor;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexOpContext;
+import edu.uci.ics.hyracks.storage.am.common.api.IModificationOperationCallback;
+import edu.uci.ics.hyracks.storage.am.common.api.ISearchOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.api.ISearchPredicate;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexAccessor;
@@ -129,8 +131,8 @@
         RTree memRTree = new RTree(memBufferCache, fieldCount, rtreeCmpFactories, memFreePageManager,
                 rtreeInteriorFrameFactory, rtreeLeafFrameFactory);
         // TODO: Do we need another operation callback here?
-        BTree memBTree = new BTree(memBufferCache, NoOpOperationCallback.INSTANCE, fieldCount, btreeCmpFactories,
-                memFreePageManager, btreeInteriorFrameFactory, btreeLeafFrameFactory);
+        BTree memBTree = new BTree(memBufferCache, fieldCount, btreeCmpFactories, memFreePageManager,
+                btreeInteriorFrameFactory, btreeLeafFrameFactory);
         memComponent = new LSMRTreeComponent(memRTree, memBTree);
         this.memFreePageManager = memFreePageManager;
         this.diskBufferCache = diskBTreeFactory.getBufferCache();
@@ -375,8 +377,10 @@
             LSMRTreeComponent component = (LSMRTreeComponent) diskTreesIter.next();
             RTree diskRTree = component.getRTree();
             BTree diskBTree = component.getBTree();
-            rTreeAccessors[diskTreeIx] = diskRTree.createAccessor();
-            bTreeAccessors[diskTreeIx] = diskBTree.createAccessor();
+            rTreeAccessors[diskTreeIx] = diskRTree.createAccessor(NoOpOperationCallback.INSTANCE,
+                    NoOpOperationCallback.INSTANCE);
+            bTreeAccessors[diskTreeIx] = diskBTree.createAccessor(NoOpOperationCallback.INSTANCE,
+                    NoOpOperationCallback.INSTANCE);
             diskTreeIx++;
         }
 
@@ -394,7 +398,8 @@
         // The RTree should be renamed before the BTree.
 
         // scan the memory RTree
-        ITreeIndexAccessor memRTreeAccessor = memComponent.getRTree().createAccessor();
+        ITreeIndexAccessor memRTreeAccessor = memComponent.getRTree().createAccessor(NoOpOperationCallback.INSTANCE,
+                NoOpOperationCallback.INSTANCE);
         RTreeSearchCursor rtreeScanCursor = (RTreeSearchCursor) memRTreeAccessor.createSearchCursor();
         SearchPredicate rtreeNullPredicate = new SearchPredicate(null, null);
         memRTreeAccessor.search(rtreeScanCursor, rtreeNullPredicate);
@@ -435,7 +440,8 @@
         diskRTree.endBulkLoad(rtreeBulkLoadCtx);
 
         // scan the memory BTree
-        ITreeIndexAccessor memBTreeAccessor = memComponent.getBTree().createAccessor();
+        ITreeIndexAccessor memBTreeAccessor = memComponent.getBTree().createAccessor(NoOpOperationCallback.INSTANCE,
+                NoOpOperationCallback.INSTANCE);
         IIndexCursor btreeScanCursor = memBTreeAccessor.createSearchCursor();
         RangePredicate btreeNullPredicate = new RangePredicate(null, null, true, true, null, null);
         memBTreeAccessor.search(btreeScanCursor, btreeNullPredicate);
@@ -551,16 +557,19 @@
     }
 
     protected LSMRTreeOpContext createOpContext() {
-        return new LSMRTreeOpContext((RTree.RTreeAccessor) memComponent.getRTree().createAccessor(),
+        return new LSMRTreeOpContext((RTree.RTreeAccessor) memComponent.getRTree().createAccessor(
+                NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE),
                 (IRTreeLeafFrame) rtreeLeafFrameFactory.createFrame(),
                 (IRTreeInteriorFrame) rtreeInteriorFrameFactory.createFrame(), memFreePageManager
                         .getMetaDataFrameFactory().createFrame(), 8, (BTree.BTreeAccessor) memComponent.getBTree()
-                        .createAccessor(), btreeLeafFrameFactory, btreeInteriorFrameFactory, memFreePageManager
-                        .getMetaDataFrameFactory().createFrame(), rtreeCmpFactories, btreeCmpFactories);
+                        .createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE),
+                btreeLeafFrameFactory, btreeInteriorFrameFactory, memFreePageManager.getMetaDataFrameFactory()
+                        .createFrame(), rtreeCmpFactories, btreeCmpFactories);
     }
 
     @Override
-    public IIndexAccessor createAccessor() {
+    public IIndexAccessor createAccessor(IModificationOperationCallback modificationCallback,
+            ISearchOperationCallback searchCallback) {
         return new LSMRTreeAccessor(lsmHarness, createOpContext());
     }
 
diff --git a/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/utils/LSMRTreeUtils.java b/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/utils/LSMRTreeUtils.java
index 94f6e1d..2a41962 100644
--- a/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/utils/LSMRTreeUtils.java
+++ b/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/utils/LSMRTreeUtils.java
@@ -25,7 +25,6 @@
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexMetaDataFrameFactory;
 import edu.uci.ics.hyracks.storage.am.common.frames.LIFOMetaDataFrameFactory;
 import edu.uci.ics.hyracks.storage.am.common.freepage.LinkedListFreePageManagerFactory;
-import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMFileManager;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMFlushPolicy;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMMergePolicy;
@@ -66,9 +65,8 @@
         RTreeFactory diskRTreeFactory = new RTreeFactory(diskBufferCache, freePageManagerFactory, rtreeCmpFactories,
                 typeTraits.length, rtreeInteriorFrameFactory, rtreeLeafFrameFactory);
         // TODO: Do we need another operation callback here?
-        BTreeFactory diskBTreeFactory = new BTreeFactory(diskBufferCache, NoOpOperationCallback.INSTANCE,
-                freePageManagerFactory, btreeCmpFactories, typeTraits.length, btreeInteriorFrameFactory,
-                btreeLeafFrameFactory);
+        BTreeFactory diskBTreeFactory = new BTreeFactory(diskBufferCache, freePageManagerFactory,
+                btreeCmpFactories, typeTraits.length, btreeInteriorFrameFactory, btreeLeafFrameFactory);
 
         ILSMFileManager fileNameManager = new LSMRTreeFileManager(ioManager, diskFileMapProvider, onDiskDir);
         LSMRTree lsmTree = new LSMRTree(memBufferCache, memFreePageManager, rtreeInteriorFrameFactory,
diff --git a/hyracks-storage-am-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/impls/RTree.java b/hyracks-storage-am-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/impls/RTree.java
index cc3cf5b..03091b0 100644
--- a/hyracks-storage-am-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/impls/RTree.java
+++ b/hyracks-storage-am-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/impls/RTree.java
@@ -28,6 +28,8 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexBulkLoadContext;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexCursor;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexOpContext;
+import edu.uci.ics.hyracks.storage.am.common.api.IModificationOperationCallback;
+import edu.uci.ics.hyracks.storage.am.common.api.ISearchOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.api.ISearchPredicate;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexAccessor;
@@ -39,6 +41,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IndexType;
 import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
 import edu.uci.ics.hyracks.storage.am.common.frames.FrameOpSpaceStatus;
+import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.impls.TreeDiskOrderScanCursor;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.IndexOp;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
@@ -856,7 +859,7 @@
 
         public BulkLoadContext(float fillFactor, IRTreeFrame leafFrame, IRTreeFrame interiorFrame,
                 ITreeIndexMetaDataFrame metaFrame) throws HyracksDataException {
-            indexAccessor = createAccessor();
+            indexAccessor = createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
         }
     }
 
@@ -928,7 +931,8 @@
     }
 
     @Override
-    public ITreeIndexAccessor createAccessor() {
+    public ITreeIndexAccessor createAccessor(IModificationOperationCallback modificationCallback,
+            ISearchOperationCallback searchCallback) {
         return new RTreeAccessor(this);
     }
 
diff --git a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexExamplesTest.java b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexExamplesTest.java
index a29be89..659325b 100644
--- a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexExamplesTest.java
+++ b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexExamplesTest.java
@@ -42,6 +42,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexCursor;
 import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
+import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.impls.TreeDiskOrderScanCursor;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
 
@@ -93,7 +94,7 @@
         }
         ArrayTupleBuilder tb = new ArrayTupleBuilder(fieldCount);
         ArrayTupleReference tuple = new ArrayTupleReference();
-        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor();
+        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
         int numInserts = 10000;
         for (int i = 0; i < numInserts; i++) {
             int f0 = rnd.nextInt() % numInserts;
@@ -172,7 +173,7 @@
         }
         ArrayTupleBuilder tb = new ArrayTupleBuilder(fieldCount);
         ArrayTupleReference tuple = new ArrayTupleReference();
-        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor();
+        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
         int numInserts = 10000;
         for (int i = 0; i < 10000; i++) {
             int f0 = rnd.nextInt() % 2000;
@@ -249,7 +250,7 @@
         }
         ArrayTupleBuilder tb = new ArrayTupleBuilder(fieldCount);
         ArrayTupleReference tuple = new ArrayTupleReference();
-        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor();
+        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
         // Max string length to be generated.
         int maxLength = 10;
         int numInserts = 10000;
@@ -324,7 +325,7 @@
 
         ArrayTupleBuilder tb = new ArrayTupleBuilder(fieldCount);
         ArrayTupleReference tuple = new ArrayTupleReference();
-        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor();
+        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
         // Max string length to be generated.
         int runs = 3;
         for (int run = 0; run < runs; run++) {
@@ -426,7 +427,7 @@
         if (LOGGER.isLoggable(Level.INFO)) {
             LOGGER.info("Inserting into tree...");
         }
-        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor();
+        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
         ArrayTupleBuilder tb = new ArrayTupleBuilder(fieldCount);
         ArrayTupleReference tuple = new ArrayTupleReference();
         int maxLength = 10;
@@ -529,7 +530,7 @@
             LOGGER.info(ins + " tuples loaded in " + (end - start) + "ms");
         }
 
-        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor();
+        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
 
         // Build low key.
         ArrayTupleBuilder lowKeyTb = new ArrayTupleBuilder(1);
diff --git a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/AbstractTreeIndexTestWorker.java b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/AbstractTreeIndexTestWorker.java
index eca9b35..60d041b 100644
--- a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/AbstractTreeIndexTestWorker.java
+++ b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/AbstractTreeIndexTestWorker.java
@@ -25,6 +25,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.datagen.DataGenThread;
 import edu.uci.ics.hyracks.storage.am.common.datagen.TupleBatch;
+import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 
 public abstract class AbstractTreeIndexTestWorker extends Thread implements ITreeIndexTestWorker {
     private Random rnd = new Random();
@@ -38,7 +39,7 @@
         this.dataGen = dataGen;
         this.opSelector = opSelector;
         this.numBatches = numBatches;
-        indexAccessor = index.createAccessor();
+        indexAccessor = index.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
     }
     
     @Override
diff --git a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TreeIndexTestContext.java b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TreeIndexTestContext.java
index bc5312c..259cf1e 100644
--- a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TreeIndexTestContext.java
+++ b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TreeIndexTestContext.java
@@ -22,6 +22,7 @@
 import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleReference;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
+import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 
 @SuppressWarnings("rawtypes")
 public abstract class TreeIndexTestContext<T extends CheckTuple> implements ITreeIndexTestContext<T> {
@@ -34,7 +35,7 @@
     public TreeIndexTestContext(ISerializerDeserializer[] fieldSerdes, ITreeIndex treeIndex) {
         this.fieldSerdes = fieldSerdes;
         this.treeIndex = treeIndex;
-        this.indexAccessor = (IIndexAccessor) treeIndex.createAccessor();
+        this.indexAccessor = (IIndexAccessor) treeIndex.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
         this.tupleBuilder = new ArrayTupleBuilder(fieldSerdes.length);
     }
 
diff --git a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/AbstractRTreeExamplesTest.java b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/AbstractRTreeExamplesTest.java
index 7192c53..baa04f5 100644
--- a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/AbstractRTreeExamplesTest.java
+++ b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/AbstractRTreeExamplesTest.java
@@ -40,6 +40,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexCursor;
 import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
+import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.impls.TreeDiskOrderScanCursor;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
 import edu.uci.ics.hyracks.storage.am.rtree.impls.SearchPredicate;
@@ -117,7 +118,7 @@
         }
         ArrayTupleBuilder tb = new ArrayTupleBuilder(fieldCount);
         ArrayTupleReference tuple = new ArrayTupleReference();
-        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor();
+        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
         int numInserts = 10000;
         for (int i = 0; i < numInserts; i++) {
             int p1x = rnd.nextInt();
@@ -224,7 +225,7 @@
         }
         ArrayTupleBuilder tb = new ArrayTupleBuilder(fieldCount);
         ArrayTupleReference tuple = new ArrayTupleReference();
-        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor();
+        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
         int numInserts = 10000;
         for (int i = 0; i < numInserts; i++) {
             double p1x = rnd.nextDouble();
@@ -319,7 +320,7 @@
 
         ArrayTupleBuilder tb = new ArrayTupleBuilder(fieldCount);
         ArrayTupleReference tuple = new ArrayTupleReference();
-        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor();
+        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
 
         int runs = 3;
         for (int run = 0; run < runs; run++) {
@@ -478,7 +479,7 @@
             LOGGER.info(numInserts + " tuples loaded in " + (end - start) + "ms");
         }
 
-        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor();
+        IIndexAccessor indexAccessor = (IIndexAccessor) treeIndex.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
 
         // Build key.
         ArrayTupleBuilder keyTb = new ArrayTupleBuilder(rtreeKeyFieldCount);
diff --git a/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeExamplesTest.java b/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeExamplesTest.java
index f4f8b12f..a89239c 100644
--- a/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeExamplesTest.java
+++ b/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeExamplesTest.java
@@ -42,8 +42,7 @@
     }
     
     protected ITreeIndex createTreeIndex(ITypeTraits[] typeTraits, IBinaryComparatorFactory[] cmpFactories) throws TreeIndexException {
-        return BTreeUtils.createBTree(harness.getBufferCache(), harness.getOpCallback(), typeTraits, cmpFactories,
-                BTreeLeafFrameType.REGULAR_NSM);
+        return BTreeUtils.createBTree(harness.getBufferCache(), typeTraits, cmpFactories, BTreeLeafFrameType.REGULAR_NSM);
     }
     
     protected int getIndexFileId() {
diff --git a/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeSearchCursorTest.java b/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeSearchCursorTest.java
index 4003cf1..46a8520 100644
--- a/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeSearchCursorTest.java
+++ b/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeSearchCursorTest.java
@@ -100,14 +100,14 @@
 
         IFreePageManager freePageManager = new LinkedListFreePageManager(bufferCache, 0, metaFrameFactory);
 
-        BTree btree = new BTree(bufferCache, NoOpOperationCallback.INSTANCE, fieldCount, cmpFactories, freePageManager, interiorFrameFactory, leafFrameFactory);
+        BTree btree = new BTree(bufferCache, fieldCount, cmpFactories, freePageManager, interiorFrameFactory, leafFrameFactory);
         btree.create(btreeFileId);
         btree.open(btreeFileId);
 
         ArrayTupleBuilder tupleBuilder = new ArrayTupleBuilder(fieldCount);
         ArrayTupleReference tuple = new ArrayTupleReference();
 
-        ITreeIndexAccessor indexAccessor = btree.createAccessor();
+        ITreeIndexAccessor indexAccessor = btree.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
 
         // generate keys
         int numKeys = 50;
@@ -173,14 +173,14 @@
 
         IFreePageManager freePageManager = new LinkedListFreePageManager(bufferCache, 0, metaFrameFactory);
 
-        BTree btree = new BTree(bufferCache, NoOpOperationCallback.INSTANCE, fieldCount, cmpFactories, freePageManager, interiorFrameFactory, leafFrameFactory);
+        BTree btree = new BTree(bufferCache, fieldCount, cmpFactories, freePageManager, interiorFrameFactory, leafFrameFactory);
         btree.create(btreeFileId);
         btree.open(btreeFileId);
 
         ArrayTupleBuilder tupleBuilder = new ArrayTupleBuilder(fieldCount);
         ArrayTupleReference tuple = new ArrayTupleReference();
 
-        ITreeIndexAccessor indexAccessor = btree.createAccessor();
+        ITreeIndexAccessor indexAccessor = btree.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
 
         // generate keys
         int numKeys = 50;
@@ -243,14 +243,14 @@
 
         IFreePageManager freePageManager = new LinkedListFreePageManager(bufferCache, 0, metaFrameFactory);
 
-        BTree btree = new BTree(bufferCache, NoOpOperationCallback.INSTANCE, fieldCount, cmpFactories, freePageManager, interiorFrameFactory, leafFrameFactory);
+        BTree btree = new BTree(bufferCache, fieldCount, cmpFactories, freePageManager, interiorFrameFactory, leafFrameFactory);
         btree.create(btreeFileId);
         btree.open(btreeFileId);
 
         ArrayTupleBuilder tupleBuilder = new ArrayTupleBuilder(fieldCount);
         ArrayTupleReference tuple = new ArrayTupleReference();
 
-        ITreeIndexAccessor indexAccessor = btree.createAccessor();
+        ITreeIndexAccessor indexAccessor = btree.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
 
         // generate keys
         int numKeys = 50;
@@ -347,7 +347,7 @@
                 ITreeIndexCursor rangeCursor = new BTreeRangeSearchCursor(leafFrame, false);
                 RangePredicate rangePred = createRangePredicate(lowKey, highKey, lowKeyInclusive,
                         highKeyInclusive);
-                ITreeIndexAccessor indexAccessor = btree.createAccessor();
+                ITreeIndexAccessor indexAccessor = btree.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
                 indexAccessor.search(rangeCursor, rangePred);
 
                 try {
diff --git a/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeStatsTest.java b/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeStatsTest.java
index c33b4e9..5b6dfe0 100644
--- a/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeStatsTest.java
+++ b/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeStatsTest.java
@@ -87,7 +87,8 @@
 
         IFreePageManager freePageManager = new LinkedListFreePageManager(bufferCache, 0, metaFrameFactory);
 
-        BTree btree = new BTree(bufferCache, NoOpOperationCallback.INSTANCE, fieldCount, cmpFactories, freePageManager, interiorFrameFactory, leafFrameFactory);
+        BTree btree = new BTree(bufferCache, fieldCount, cmpFactories, freePageManager, interiorFrameFactory,
+                leafFrameFactory);
         btree.create(fileId);
         btree.open(fileId);
 
@@ -112,7 +113,8 @@
         accessor.reset(frame);
         FrameTupleReference tuple = new FrameTupleReference();
 
-        ITreeIndexAccessor indexAccessor = btree.createAccessor();
+        ITreeIndexAccessor indexAccessor = btree.createAccessor(NoOpOperationCallback.INSTANCE,
+                NoOpOperationCallback.INSTANCE);
         // 10000
         for (int i = 0; i < 100000; i++) {
 
diff --git a/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeUpdateSearchTest.java b/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeUpdateSearchTest.java
index 2b03a6a..0a1c193 100644
--- a/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeUpdateSearchTest.java
+++ b/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/BTreeUpdateSearchTest.java
@@ -42,7 +42,7 @@
     public void test01() throws Exception {
         IBufferCache bufferCache = harness.getBufferCache();
         int btreeFileId = harness.getBTreeFileId();
-        
+
         // declare fields
         int fieldCount = 2;
         ITypeTraits[] typeTraits = new ITypeTraits[fieldCount];
@@ -65,7 +65,8 @@
         IBTreeLeafFrame leafFrame = (IBTreeLeafFrame) leafFrameFactory.createFrame();
 
         IFreePageManager freePageManager = new LinkedListFreePageManager(bufferCache, 0, metaFrameFactory);
-        BTree btree = new BTree(bufferCache, NoOpOperationCallback.INSTANCE, fieldCount, cmpFactories, freePageManager, interiorFrameFactory, leafFrameFactory);
+        BTree btree = new BTree(bufferCache, fieldCount, cmpFactories, freePageManager, interiorFrameFactory,
+                leafFrameFactory);
         btree.create(btreeFileId);
         btree.open(btreeFileId);
 
@@ -80,7 +81,8 @@
 
         ArrayTupleBuilder tb = new ArrayTupleBuilder(fieldCount);
         ArrayTupleReference insertTuple = new ArrayTupleReference();
-        ITreeIndexAccessor indexAccessor = btree.createAccessor();
+        ITreeIndexAccessor indexAccessor = btree.createAccessor(NoOpOperationCallback.INSTANCE,
+                NoOpOperationCallback.INSTANCE);
 
         int numInserts = 10000;
         for (int i = 0; i < numInserts; i++) {
diff --git a/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/multithread/BTreeMultiThreadTest.java b/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/multithread/BTreeMultiThreadTest.java
index 596fa31..26919b0 100644
--- a/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/multithread/BTreeMultiThreadTest.java
+++ b/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/multithread/BTreeMultiThreadTest.java
@@ -48,7 +48,7 @@
 
     @Override
     protected ITreeIndex createTreeIndex(ITypeTraits[] typeTraits, IBinaryComparatorFactory[] cmpFactories) throws TreeIndexException {
-        return BTreeUtils.createBTree(harness.getBufferCache(), harness.getOpCallback(), typeTraits, cmpFactories, BTreeLeafFrameType.REGULAR_NSM);
+        return BTreeUtils.createBTree(harness.getBufferCache(), typeTraits, cmpFactories, BTreeLeafFrameType.REGULAR_NSM);
     }
 
     @Override
diff --git a/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/util/BTreeTestContext.java b/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/util/BTreeTestContext.java
index b820f93..8442131 100644
--- a/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/util/BTreeTestContext.java
+++ b/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/util/BTreeTestContext.java
@@ -23,7 +23,6 @@
 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.common.api.ITreeIndex;
-import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.common.buffercache.IBufferCache;
 
 @SuppressWarnings("rawtypes")
@@ -48,7 +47,7 @@
     public static BTreeTestContext create(IBufferCache bufferCache, int btreeFileId, ISerializerDeserializer[] fieldSerdes, int numKeyFields, BTreeLeafFrameType leafType) throws Exception {        
         ITypeTraits[] typeTraits = SerdeUtils.serdesToTypeTraits(fieldSerdes);
         IBinaryComparatorFactory[] cmpFactories = SerdeUtils.serdesToComparatorFactories(fieldSerdes, numKeyFields);
-        BTree btree = BTreeUtils.createBTree(bufferCache, NoOpOperationCallback.INSTANCE, typeTraits, cmpFactories, leafType);
+        BTree btree = BTreeUtils.createBTree(bufferCache, typeTraits, cmpFactories, leafType);
         btree.create(btreeFileId);
         btree.open(btreeFileId);
         BTreeTestContext testCtx = new BTreeTestContext(fieldSerdes, btree);
diff --git a/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/util/BTreeTestHarness.java b/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/util/BTreeTestHarness.java
index 1b450d8..f5f8af5 100644
--- a/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/util/BTreeTestHarness.java
+++ b/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/util/BTreeTestHarness.java
@@ -24,52 +24,50 @@
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.api.io.FileReference;
 import edu.uci.ics.hyracks.storage.am.btree.frames.BTreeLeafFrameType;
-import edu.uci.ics.hyracks.storage.am.common.api.IOperationCallback;
-import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.common.buffercache.IBufferCache;
 import edu.uci.ics.hyracks.storage.common.file.IFileMapProvider;
 import edu.uci.ics.hyracks.test.support.TestStorageManagerComponentHolder;
 import edu.uci.ics.hyracks.test.support.TestUtils;
 
-public class BTreeTestHarness {    
+public class BTreeTestHarness {
     public static final BTreeLeafFrameType[] LEAF_FRAMES_TO_TEST = new BTreeLeafFrameType[] {
-        BTreeLeafFrameType.REGULAR_NSM, BTreeLeafFrameType.FIELD_PREFIX_COMPRESSED_NSM };
-    
+            BTreeLeafFrameType.REGULAR_NSM, BTreeLeafFrameType.FIELD_PREFIX_COMPRESSED_NSM };
+
     private static final long RANDOM_SEED = 50;
     private static final int DEFAULT_PAGE_SIZE = 256;
     private static final int DEFAULT_NUM_PAGES = 100;
     private static final int DEFAULT_MAX_OPEN_FILES = 10;
     private static final int DEFAULT_HYRACKS_FRAME_SIZE = 128;
-    
+
     protected final int pageSize;
     protected final int numPages;
     protected final int maxOpenFiles;
     protected final int hyracksFrameSize;
-        
-    protected IHyracksTaskContext ctx; 
+
+    protected IHyracksTaskContext ctx;
     protected IBufferCache bufferCache;
     protected int btreeFileId;
-    
+
     protected final Random rnd = new Random();
     protected final SimpleDateFormat simpleDateFormat = new SimpleDateFormat("ddMMyy-hhmmssSS");
     protected final String tmpDir = System.getProperty("java.io.tmpdir");
     protected final String sep = System.getProperty("file.separator");
     protected String fileName;
-    
+
     public BTreeTestHarness() {
-    	this.pageSize = DEFAULT_PAGE_SIZE;
-    	this.numPages = DEFAULT_NUM_PAGES;
-    	this.maxOpenFiles = DEFAULT_MAX_OPEN_FILES;
-    	this.hyracksFrameSize = DEFAULT_HYRACKS_FRAME_SIZE;
+        this.pageSize = DEFAULT_PAGE_SIZE;
+        this.numPages = DEFAULT_NUM_PAGES;
+        this.maxOpenFiles = DEFAULT_MAX_OPEN_FILES;
+        this.hyracksFrameSize = DEFAULT_HYRACKS_FRAME_SIZE;
     }
-    
+
     public BTreeTestHarness(int pageSize, int numPages, int maxOpenFiles, int hyracksFrameSize) {
-    	this.pageSize = pageSize;
-    	this.numPages = numPages;
-    	this.maxOpenFiles = maxOpenFiles;
-    	this.hyracksFrameSize = hyracksFrameSize;
+        this.pageSize = pageSize;
+        this.numPages = numPages;
+        this.maxOpenFiles = maxOpenFiles;
+        this.hyracksFrameSize = hyracksFrameSize;
     }
-    
+
     public void setUp() throws HyracksDataException {
         fileName = tmpDir + sep + simpleDateFormat.format(new Date());
         ctx = TestUtils.create(getHyracksFrameSize());
@@ -82,51 +80,47 @@
         bufferCache.openFile(btreeFileId);
         rnd.setSeed(RANDOM_SEED);
     }
-    
+
     public void tearDown() throws HyracksDataException {
         bufferCache.closeFile(btreeFileId);
         bufferCache.close();
         File f = new File(fileName);
         f.deleteOnExit();
     }
-    
+
     public IHyracksTaskContext getHyracksTaskContext() {
-    	return ctx;
+        return ctx;
     }
-    
+
     public IBufferCache getBufferCache() {
-    	return bufferCache;
+        return bufferCache;
     }
-    
+
     public int getBTreeFileId() {
-    	return btreeFileId;
+        return btreeFileId;
     }
-    
+
     public String getFileName() {
         return fileName;
     }
-    
+
     public Random getRandom() {
-    	return rnd;
+        return rnd;
     }
-    
+
     public int getPageSize() {
         return pageSize;
     }
-    
+
     public int getNumPages() {
         return numPages;
     }
-    
+
     public int getHyracksFrameSize() {
         return hyracksFrameSize;
     }
-    
+
     public int getMaxOpenFiles() {
         return maxOpenFiles;
     }
-    
-    public IOperationCallback getOpCallback() {
-        return NoOpOperationCallback.INSTANCE;
-    }
 }
diff --git a/hyracks-tests/hyracks-storage-am-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/invertedindex/AbstractInvIndexSearchTest.java b/hyracks-tests/hyracks-storage-am-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/invertedindex/AbstractInvIndexSearchTest.java
index c5055a6..9962ef4 100644
--- a/hyracks-tests/hyracks-storage-am-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/invertedindex/AbstractInvIndexSearchTest.java
+++ b/hyracks-tests/hyracks-storage-am-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/invertedindex/AbstractInvIndexSearchTest.java
@@ -47,7 +47,6 @@
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexMetaDataFrameFactory;
 import edu.uci.ics.hyracks.storage.am.common.frames.LIFOMetaDataFrameFactory;
 import edu.uci.ics.hyracks.storage.am.common.freepage.LinkedListFreePageManager;
-import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.tuples.TypeAwareTupleWriterFactory;
 import edu.uci.ics.hyracks.storage.am.invertedindex.api.IInvertedListBuilder;
 import edu.uci.ics.hyracks.storage.am.invertedindex.impls.FixedSizeElementInvertedListBuilder;
@@ -158,8 +157,8 @@
 
         freePageManager = new LinkedListFreePageManager(bufferCache, 0, metaFrameFactory);
 
-        btree = new BTree(bufferCache, NoOpOperationCallback.INSTANCE, btreeTypeTraits.length, btreeCmpFactories,
-                freePageManager, interiorFrameFactory, leafFrameFactory);
+        btree = new BTree(bufferCache, btreeTypeTraits.length, btreeCmpFactories, freePageManager,
+                interiorFrameFactory, leafFrameFactory);
         btree.create(btreeFileId);
         btree.open(btreeFileId);
 
diff --git a/hyracks-tests/hyracks-storage-am-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/invertedindex/BulkLoadTest.java b/hyracks-tests/hyracks-storage-am-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/invertedindex/BulkLoadTest.java
index 49c3723..4c78c2b 100644
--- a/hyracks-tests/hyracks-storage-am-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/invertedindex/BulkLoadTest.java
+++ b/hyracks-tests/hyracks-storage-am-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/invertedindex/BulkLoadTest.java
@@ -123,8 +123,8 @@
 
         IFreePageManager freePageManager = new LinkedListFreePageManager(bufferCache, 0, metaFrameFactory);
 
-        BTree btree = new BTree(bufferCache, NoOpOperationCallback.INSTANCE, btreeTypeTraits.length, cmpFactories,
-                freePageManager, interiorFrameFactory, leafFrameFactory);
+        BTree btree = new BTree(bufferCache, btreeTypeTraits.length, cmpFactories, freePageManager,
+                interiorFrameFactory, leafFrameFactory);
         btree.create(btreeFileId);
         btree.open(btreeFileId);
 
@@ -137,7 +137,8 @@
         invListCmpFactories[0] = PointableBinaryComparatorFactory.of(IntegerPointable.FACTORY);
 
         IInvertedListBuilder invListBuilder = new FixedSizeElementInvertedListBuilder(invListTypeTraits);
-        InvertedIndex invIndex = new InvertedIndex(bufferCache, btree, invListTypeTraits, invListCmpFactories, invListBuilder, null);
+        InvertedIndex invIndex = new InvertedIndex(bufferCache, btree, invListTypeTraits, invListCmpFactories,
+                invListBuilder, null);
         invIndex.open(invListsFileId);
 
         Random rnd = new Random();
@@ -224,7 +225,8 @@
         IFrameTupleAccessor tokenAccessor = new FrameTupleAccessor(stageletCtx.getFrameSize(), tokenRecDesc);
         tokenAccessor.reset(frame);
 
-        ITreeIndexAccessor btreeAccessor = invIndex.getBTree().createAccessor();
+        ITreeIndexAccessor btreeAccessor = invIndex.getBTree().createAccessor(NoOpOperationCallback.INSTANCE,
+                NoOpOperationCallback.INSTANCE);
 
         // verify created inverted lists one-by-one
         for (int i = 0; i < tokens.size(); i++) {
diff --git a/hyracks-tests/hyracks-storage-am-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/invertedindex/SearchPerfTest.java b/hyracks-tests/hyracks-storage-am-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/invertedindex/SearchPerfTest.java
index ef0a6fb..11ae4a6 100644
--- a/hyracks-tests/hyracks-storage-am-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/invertedindex/SearchPerfTest.java
+++ b/hyracks-tests/hyracks-storage-am-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/invertedindex/SearchPerfTest.java
@@ -30,6 +30,7 @@
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTree;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexBulkLoadContext;
 import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
+import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.invertedindex.api.IInvertedIndexSearchModifier;
 import edu.uci.ics.hyracks.storage.am.invertedindex.impls.InvertedIndex.InvertedIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.invertedindex.impls.InvertedIndexSearchPredicate;
@@ -51,253 +52,245 @@
  */
 public class SearchPerfTest extends AbstractInvIndexSearchTest {
 
-	protected List<String> tokens = new ArrayList<String>();
+    protected List<String> tokens = new ArrayList<String>();
 
-	@Override
-	protected void setTokenizer() {
-		tokenFactory = new UTF8WordTokenFactory();
-		tokenizer = new DelimitedUTF8StringBinaryTokenizer(true, false,
-				tokenFactory);
-	}
-	
-	@Before
-	public void start() throws Exception {
-		super.start();
-		loadData();
-	}
+    @Override
+    protected void setTokenizer() {
+        tokenFactory = new UTF8WordTokenFactory();
+        tokenizer = new DelimitedUTF8StringBinaryTokenizer(true, false, tokenFactory);
+    }
 
-	public void loadData() throws HyracksDataException, TreeIndexException {
-		tokens.add("compilers");
-		tokens.add("computer");
-		tokens.add("databases");
-		tokens.add("fast");
-		tokens.add("hyracks");
-		tokens.add("major");
-		tokens.add("science");
-		tokens.add("systems");
-		tokens.add("university");
+    @Before
+    public void start() throws Exception {
+        super.start();
+        loadData();
+    }
 
-		for (int i = 0; i < tokens.size(); i++) {
-			checkInvLists.add(new ArrayList<Integer>());
-		}
+    public void loadData() throws HyracksDataException, TreeIndexException {
+        tokens.add("compilers");
+        tokens.add("computer");
+        tokens.add("databases");
+        tokens.add("fast");
+        tokens.add("hyracks");
+        tokens.add("major");
+        tokens.add("science");
+        tokens.add("systems");
+        tokens.add("university");
 
-		// for generating length-skewed inverted lists
-		int addProb = 0;
-		int addProbStep = 10;
+        for (int i = 0; i < tokens.size(); i++) {
+            checkInvLists.add(new ArrayList<Integer>());
+        }
 
-		IIndexBulkLoadContext ctx = invIndex.beginBulkLoad(BTree.DEFAULT_FILL_FACTOR);
+        // for generating length-skewed inverted lists
+        int addProb = 0;
+        int addProbStep = 10;
 
-		for (int i = 0; i < tokens.size(); i++) {
+        IIndexBulkLoadContext ctx = invIndex.beginBulkLoad(BTree.DEFAULT_FILL_FACTOR);
 
-			addProb += addProbStep * (i + 1);
-			for (int j = 0; j < maxId; j++) {
-				if ((Math.abs(rnd.nextInt()) % addProb) == 0) {
-					tb.reset();
-					UTF8StringSerializerDeserializer.INSTANCE.serialize(
-							tokens.get(i), tb.getDataOutput());
-					tb.addFieldEndOffset();
-					IntegerSerializerDeserializer.INSTANCE.serialize(j, tb.getDataOutput());
-					tb.addFieldEndOffset();
-					tuple.reset(tb.getFieldEndOffsets(), tb.getByteArray());
-					checkInvLists.get(i).add(j);
-					try {
-						invIndex.bulkLoadAddTuple(tuple, ctx);
-					} catch (Exception e) {
-						e.printStackTrace();
-					}
-				}
-			}
-		}
-		invIndex.endBulkLoad(ctx);
-	}
+        for (int i = 0; i < tokens.size(); i++) {
 
-	/**
-	 * Determine the expected results with the ScanCount algorithm. The
-	 * ScanCount algorithm is very simple, so we can be confident the results
-	 * are correct.
-	 * 
-	 */
-	protected void fillExpectedResults(int[] queryTokenIndexes,
-			int numQueryTokens, int occurrenceThreshold) {
-		// reset scan count array
-		for (int i = 0; i < maxId; i++) {
-			scanCountArray[i] = 0;
-		}
+            addProb += addProbStep * (i + 1);
+            for (int j = 0; j < maxId; j++) {
+                if ((Math.abs(rnd.nextInt()) % addProb) == 0) {
+                    tb.reset();
+                    UTF8StringSerializerDeserializer.INSTANCE.serialize(tokens.get(i), tb.getDataOutput());
+                    tb.addFieldEndOffset();
+                    IntegerSerializerDeserializer.INSTANCE.serialize(j, tb.getDataOutput());
+                    tb.addFieldEndOffset();
+                    tuple.reset(tb.getFieldEndOffsets(), tb.getByteArray());
+                    checkInvLists.get(i).add(j);
+                    try {
+                        invIndex.bulkLoadAddTuple(tuple, ctx);
+                    } catch (Exception e) {
+                        e.printStackTrace();
+                    }
+                }
+            }
+        }
+        invIndex.endBulkLoad(ctx);
+    }
 
-		// count occurrences
-		for (int i = 0; i < numQueryTokens; i++) {
-			ArrayList<Integer> list = checkInvLists.get(queryTokenIndexes[i]);
-			for (int j = 0; j < list.size(); j++) {
-				scanCountArray[list.get(j)]++;
-			}
-		}
+    /**
+     * Determine the expected results with the ScanCount algorithm. The
+     * ScanCount algorithm is very simple, so we can be confident the results
+     * are correct.
+     * 
+     */
+    protected void fillExpectedResults(int[] queryTokenIndexes, int numQueryTokens, int occurrenceThreshold) {
+        // reset scan count array
+        for (int i = 0; i < maxId; i++) {
+            scanCountArray[i] = 0;
+        }
 
-		// check threshold
-		expectedResults.clear();
-		for (int i = 0; i < maxId; i++) {
-			if (scanCountArray[i] >= occurrenceThreshold) {
-				expectedResults.add(i);
-			}
-		}
-	}
+        // count occurrences
+        for (int i = 0; i < numQueryTokens; i++) {
+            ArrayList<Integer> list = checkInvLists.get(queryTokenIndexes[i]);
+            for (int j = 0; j < list.size(); j++) {
+                scanCountArray[list.get(j)]++;
+            }
+        }
 
-	/**
-	 * Generates a specified number of queries. Each query consists of a set of
-	 * randomly chosen tokens that are picked from the pre-defined set of
-	 * tokens. We run each query, measure it's time, and verify it's results
-	 * against the results produced by ScanCount, implemented in
-	 * fillExpectedResults().
-	 * 
-	 */
-	private void runQueries(IInvertedIndexSearchModifier searchModifier,
-			int numQueries) throws Exception {
+        // check threshold
+        expectedResults.clear();
+        for (int i = 0; i < maxId; i++) {
+            if (scanCountArray[i] >= occurrenceThreshold) {
+                expectedResults.add(i);
+            }
+        }
+    }
 
-		rnd.setSeed(50);
+    /**
+     * Generates a specified number of queries. Each query consists of a set of
+     * randomly chosen tokens that are picked from the pre-defined set of
+     * tokens. We run each query, measure it's time, and verify it's results
+     * against the results produced by ScanCount, implemented in
+     * fillExpectedResults().
+     * 
+     */
+    private void runQueries(IInvertedIndexSearchModifier searchModifier, int numQueries) throws Exception {
 
-		InvertedIndexAccessor accessor = (InvertedIndexAccessor) invIndex.createAccessor();
-		InvertedIndexSearchPredicate searchPred = new InvertedIndexSearchPredicate(searchModifier);
-		
-		// generate random queries
-		int[] queryTokenIndexes = new int[tokens.size()];
-		for (int i = 0; i < numQueries; i++) {
+        rnd.setSeed(50);
 
-			int numQueryTokens = Math.abs(rnd.nextInt() % tokens.size()) + 1;
-			for (int j = 0; j < numQueryTokens; j++) {
-				queryTokenIndexes[j] = Math.abs(rnd.nextInt() % tokens.size());
-			}
+        InvertedIndexAccessor accessor = (InvertedIndexAccessor) invIndex.createAccessor(
+                NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
+        InvertedIndexSearchPredicate searchPred = new InvertedIndexSearchPredicate(searchModifier);
 
-			StringBuilder strBuilder = new StringBuilder();
-			for (int j = 0; j < numQueryTokens; j++) {
-				strBuilder.append(tokens.get(queryTokenIndexes[j]));
-				if (j + 1 != numQueryTokens) {
-					strBuilder.append(" ");
-				}
-			}
+        // generate random queries
+        int[] queryTokenIndexes = new int[tokens.size()];
+        for (int i = 0; i < numQueries; i++) {
 
-			String queryString = strBuilder.toString();
+            int numQueryTokens = Math.abs(rnd.nextInt() % tokens.size()) + 1;
+            for (int j = 0; j < numQueryTokens; j++) {
+                queryTokenIndexes[j] = Math.abs(rnd.nextInt() % tokens.size());
+            }
 
-			// Serialize query.
-			queryTb.reset();
-			UTF8StringSerializerDeserializer.INSTANCE.serialize(queryString,
-					queryTb.getDataOutput());
-			queryTb.addFieldEndOffset();
-			queryTuple.reset(queryTb.getFieldEndOffsets(), queryTb.getByteArray());
+            StringBuilder strBuilder = new StringBuilder();
+            for (int j = 0; j < numQueryTokens; j++) {
+                strBuilder.append(tokens.get(queryTokenIndexes[j]));
+                if (j + 1 != numQueryTokens) {
+                    strBuilder.append(" ");
+                }
+            }
 
-			// Set query tuple in search predicate.
-			searchPred.setQueryTuple(queryTuple);
-			searchPred.setQueryFieldIndex(0);
-			
-			boolean panic = false;
+            String queryString = strBuilder.toString();
 
-			resultCursor = accessor.createSearchCursor();
-			int repeats = 1;
-			double totalTime = 0;
-			for (int j = 0; j < repeats; j++) {
-				long timeStart = System.currentTimeMillis();
-				try {
-					resultCursor.reset();
-					accessor.search(resultCursor, searchPred);
-				} catch (OccurrenceThresholdPanicException e) {
-					panic = true;
-				}
-				long timeEnd = System.currentTimeMillis();
-				totalTime += timeEnd - timeStart;
-			}
-			double avgTime = totalTime / (double) repeats;
-			if (LOGGER.isLoggable(Level.INFO)) {
-				LOGGER.info(i + ": " + "\"" + queryString + "\": " + avgTime
-						+ "ms");
-			}
+            // Serialize query.
+            queryTb.reset();
+            UTF8StringSerializerDeserializer.INSTANCE.serialize(queryString, queryTb.getDataOutput());
+            queryTb.addFieldEndOffset();
+            queryTuple.reset(queryTb.getFieldEndOffsets(), queryTb.getByteArray());
 
-			if (!panic) {
-				TOccurrenceSearcher searcher = (TOccurrenceSearcher) accessor.getSearcher();
-				fillExpectedResults(queryTokenIndexes, numQueryTokens,
-						searcher.getOccurrenceThreshold());
-				// verify results
-				int checkIndex = 0;
-				while (resultCursor.hasNext()) {
-					resultCursor.next();
-					ITupleReference resultTuple = resultCursor.getTuple();
-					int id = IntegerSerializerDeserializer.getInt(
-							resultTuple.getFieldData(0),
-							resultTuple.getFieldStart(0));
-					Assert.assertEquals(expectedResults.get(checkIndex)
-							.intValue(), id);
-					checkIndex++;
-				}
+            // Set query tuple in search predicate.
+            searchPred.setQueryTuple(queryTuple);
+            searchPred.setQueryFieldIndex(0);
 
-				if (expectedResults.size() != checkIndex) {
-					if (LOGGER.isLoggable(Level.INFO)) {
-						LOGGER.info("CHECKING");
-					}
-					StringBuilder expectedStrBuilder = new StringBuilder();
-					for (Integer x : expectedResults) {
-						expectedStrBuilder.append(x + " ");
-					}
-					if (LOGGER.isLoggable(Level.INFO)) {
-						LOGGER.info(expectedStrBuilder.toString());
-					}
-				}
+            boolean panic = false;
 
-				Assert.assertEquals(expectedResults.size(), checkIndex);
-			}
-		}
-	}
+            resultCursor = accessor.createSearchCursor();
+            int repeats = 1;
+            double totalTime = 0;
+            for (int j = 0; j < repeats; j++) {
+                long timeStart = System.currentTimeMillis();
+                try {
+                    resultCursor.reset();
+                    accessor.search(resultCursor, searchPred);
+                } catch (OccurrenceThresholdPanicException e) {
+                    panic = true;
+                }
+                long timeEnd = System.currentTimeMillis();
+                totalTime += timeEnd - timeStart;
+            }
+            double avgTime = totalTime / (double) repeats;
+            if (LOGGER.isLoggable(Level.INFO)) {
+                LOGGER.info(i + ": " + "\"" + queryString + "\": " + avgTime + "ms");
+            }
 
-	/**
-	 * Runs 50 random conjunctive search queries to test the
-	 * ConjunctiveSearchModifier.
-	 * 
-	 */
-	@Test
-	public void conjunctiveKeywordQueryTest() throws Exception {
-		IInvertedIndexSearchModifier searchModifier = new ConjunctiveSearchModifier();
-		runQueries(searchModifier, 50);
-	}
+            if (!panic) {
+                TOccurrenceSearcher searcher = (TOccurrenceSearcher) accessor.getSearcher();
+                fillExpectedResults(queryTokenIndexes, numQueryTokens, searcher.getOccurrenceThreshold());
+                // verify results
+                int checkIndex = 0;
+                while (resultCursor.hasNext()) {
+                    resultCursor.next();
+                    ITupleReference resultTuple = resultCursor.getTuple();
+                    int id = IntegerSerializerDeserializer.getInt(resultTuple.getFieldData(0),
+                            resultTuple.getFieldStart(0));
+                    Assert.assertEquals(expectedResults.get(checkIndex).intValue(), id);
+                    checkIndex++;
+                }
 
-	/**
-	 * Runs 50 random jaccard-based search queries with thresholds 1.0, 0.9,
-	 * 0.8, 0.7, 0.6, 0.5. Tests the JaccardSearchModifier.
-	 * 
-	 */
-	@Test
-	public void jaccardKeywordQueryTest() throws Exception {
-		JaccardSearchModifier searchModifier = new JaccardSearchModifier(1.0f);
+                if (expectedResults.size() != checkIndex) {
+                    if (LOGGER.isLoggable(Level.INFO)) {
+                        LOGGER.info("CHECKING");
+                    }
+                    StringBuilder expectedStrBuilder = new StringBuilder();
+                    for (Integer x : expectedResults) {
+                        expectedStrBuilder.append(x + " ");
+                    }
+                    if (LOGGER.isLoggable(Level.INFO)) {
+                        LOGGER.info(expectedStrBuilder.toString());
+                    }
+                }
 
-		if (LOGGER.isLoggable(Level.INFO)) {
-			LOGGER.info("JACCARD: " + 1.0f);
-		}
-		searchModifier.setJaccThresh(1.0f);
-		runQueries(searchModifier, 50);
+                Assert.assertEquals(expectedResults.size(), checkIndex);
+            }
+        }
+    }
 
-		if (LOGGER.isLoggable(Level.INFO)) {
-			LOGGER.info("JACCARD: " + 0.9f);
-		}
-		searchModifier.setJaccThresh(0.9f);
-		runQueries(searchModifier, 50);
+    /**
+     * Runs 50 random conjunctive search queries to test the
+     * ConjunctiveSearchModifier.
+     * 
+     */
+    @Test
+    public void conjunctiveKeywordQueryTest() throws Exception {
+        IInvertedIndexSearchModifier searchModifier = new ConjunctiveSearchModifier();
+        runQueries(searchModifier, 50);
+    }
 
-		if (LOGGER.isLoggable(Level.INFO)) {
-			LOGGER.info("JACCARD: " + 0.8f);
-		}
-		searchModifier.setJaccThresh(0.8f);
-		runQueries(searchModifier, 50);
+    /**
+     * Runs 50 random jaccard-based search queries with thresholds 1.0, 0.9,
+     * 0.8, 0.7, 0.6, 0.5. Tests the JaccardSearchModifier.
+     * 
+     */
+    @Test
+    public void jaccardKeywordQueryTest() throws Exception {
+        JaccardSearchModifier searchModifier = new JaccardSearchModifier(1.0f);
 
-		if (LOGGER.isLoggable(Level.INFO)) {
-			LOGGER.info("JACCARD: " + 0.7f);
-		}
-		searchModifier.setJaccThresh(0.7f);
-		runQueries(searchModifier, 50);
+        if (LOGGER.isLoggable(Level.INFO)) {
+            LOGGER.info("JACCARD: " + 1.0f);
+        }
+        searchModifier.setJaccThresh(1.0f);
+        runQueries(searchModifier, 50);
 
-		if (LOGGER.isLoggable(Level.INFO)) {
-			LOGGER.info("JACCARD: " + 0.6f);
-		}
-		searchModifier.setJaccThresh(0.6f);
-		runQueries(searchModifier, 50);
+        if (LOGGER.isLoggable(Level.INFO)) {
+            LOGGER.info("JACCARD: " + 0.9f);
+        }
+        searchModifier.setJaccThresh(0.9f);
+        runQueries(searchModifier, 50);
 
-		if (LOGGER.isLoggable(Level.INFO)) {
-			LOGGER.info("JACCARD: " + 0.5f);
-		}
-		searchModifier.setJaccThresh(0.5f);
-		runQueries(searchModifier, 50);
-	}
+        if (LOGGER.isLoggable(Level.INFO)) {
+            LOGGER.info("JACCARD: " + 0.8f);
+        }
+        searchModifier.setJaccThresh(0.8f);
+        runQueries(searchModifier, 50);
+
+        if (LOGGER.isLoggable(Level.INFO)) {
+            LOGGER.info("JACCARD: " + 0.7f);
+        }
+        searchModifier.setJaccThresh(0.7f);
+        runQueries(searchModifier, 50);
+
+        if (LOGGER.isLoggable(Level.INFO)) {
+            LOGGER.info("JACCARD: " + 0.6f);
+        }
+        searchModifier.setJaccThresh(0.6f);
+        runQueries(searchModifier, 50);
+
+        if (LOGGER.isLoggable(Level.INFO)) {
+            LOGGER.info("JACCARD: " + 0.5f);
+        }
+        searchModifier.setJaccThresh(0.5f);
+        runQueries(searchModifier, 50);
+    }
 }
diff --git a/hyracks-tests/hyracks-storage-am-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/invertedindex/SearchTest.java b/hyracks-tests/hyracks-storage-am-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/invertedindex/SearchTest.java
index 49295d2..933e848 100644
--- a/hyracks-tests/hyracks-storage-am-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/invertedindex/SearchTest.java
+++ b/hyracks-tests/hyracks-storage-am-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/invertedindex/SearchTest.java
@@ -33,6 +33,7 @@
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTree;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexBulkLoadContext;
 import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
+import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.invertedindex.api.IInvertedIndexSearchModifier;
 import edu.uci.ics.hyracks.storage.am.invertedindex.impls.InvertedIndex.InvertedIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.invertedindex.impls.InvertedIndexSearchPredicate;
@@ -46,263 +47,256 @@
 
 public class SearchTest extends AbstractInvIndexSearchTest {
 
-	protected List<String> dataStrings = new ArrayList<String>();
-	protected List<String> firstNames = new ArrayList<String>();
-	protected List<String> lastNames = new ArrayList<String>();
+    protected List<String> dataStrings = new ArrayList<String>();
+    protected List<String> firstNames = new ArrayList<String>();
+    protected List<String> lastNames = new ArrayList<String>();
 
-	protected IBinaryComparator[] btreeBinCmps;
-	
-	@Override
-	protected void setTokenizer() {
-		tokenFactory = new UTF8NGramTokenFactory();
-		tokenizer = new NGramUTF8StringBinaryTokenizer(3, false, true, false,
-				tokenFactory);
-	}
-	
-	@Before
-	public void start() throws Exception {
-		super.start();
-		btreeBinCmps = new IBinaryComparator[btreeCmpFactories.length];
-		for (int i = 0; i < btreeCmpFactories.length; i++) {
-			btreeBinCmps[i] = btreeCmpFactories[i].createBinaryComparator();
-		}
-		generateDataStrings();
-		loadData();
-	}
+    protected IBinaryComparator[] btreeBinCmps;
 
-	public void generateDataStrings() {
-		firstNames.add("Kathrin");
-		firstNames.add("Cathrin");
-		firstNames.add("Kathryn");
-		firstNames.add("Cathryn");
-		firstNames.add("Kathrine");
-		firstNames.add("Cathrine");
-		firstNames.add("Kathryne");
-		firstNames.add("Cathryne");
-		firstNames.add("Katherin");
-		firstNames.add("Catherin");
-		firstNames.add("Katheryn");
-		firstNames.add("Catheryn");
-		firstNames.add("Katherine");
-		firstNames.add("Catherine");
-		firstNames.add("Katheryne");
-		firstNames.add("Catheryne");
-		firstNames.add("John");
-		firstNames.add("Jack");
-		firstNames.add("Jonathan");
-		firstNames.add("Nathan");
+    @Override
+    protected void setTokenizer() {
+        tokenFactory = new UTF8NGramTokenFactory();
+        tokenizer = new NGramUTF8StringBinaryTokenizer(3, false, true, false, tokenFactory);
+    }
 
-		lastNames.add("Miller");
-		lastNames.add("Myller");
-		lastNames.add("Keller");
-		lastNames.add("Ketler");
-		lastNames.add("Muller");
-		lastNames.add("Fuller");
-		lastNames.add("Smith");
-		lastNames.add("Smyth");
-		lastNames.add("Smithe");
-		lastNames.add("Smythe");
+    @Before
+    public void start() throws Exception {
+        super.start();
+        btreeBinCmps = new IBinaryComparator[btreeCmpFactories.length];
+        for (int i = 0; i < btreeCmpFactories.length; i++) {
+            btreeBinCmps[i] = btreeCmpFactories[i].createBinaryComparator();
+        }
+        generateDataStrings();
+        loadData();
+    }
 
-		// Generate all 'firstName lastName' combinations as data strings
-		for (String f : firstNames) {
-			for (String l : lastNames) {
-				dataStrings.add(f + " " + l);
-			}
-		}
-	}
+    public void generateDataStrings() {
+        firstNames.add("Kathrin");
+        firstNames.add("Cathrin");
+        firstNames.add("Kathryn");
+        firstNames.add("Cathryn");
+        firstNames.add("Kathrine");
+        firstNames.add("Cathrine");
+        firstNames.add("Kathryne");
+        firstNames.add("Cathryne");
+        firstNames.add("Katherin");
+        firstNames.add("Catherin");
+        firstNames.add("Katheryn");
+        firstNames.add("Catheryn");
+        firstNames.add("Katherine");
+        firstNames.add("Catherine");
+        firstNames.add("Katheryne");
+        firstNames.add("Catheryne");
+        firstNames.add("John");
+        firstNames.add("Jack");
+        firstNames.add("Jonathan");
+        firstNames.add("Nathan");
 
-	private class TokenIdPair implements Comparable<TokenIdPair> {
-		public ByteArrayAccessibleOutputStream baaos = new ByteArrayAccessibleOutputStream();
-		public DataOutputStream dos = new DataOutputStream(baaos);
-		public int id;
+        lastNames.add("Miller");
+        lastNames.add("Myller");
+        lastNames.add("Keller");
+        lastNames.add("Ketler");
+        lastNames.add("Muller");
+        lastNames.add("Fuller");
+        lastNames.add("Smith");
+        lastNames.add("Smyth");
+        lastNames.add("Smithe");
+        lastNames.add("Smythe");
 
-		TokenIdPair(IToken token, int id) throws IOException {
-			token.serializeToken(dos);
-			this.id = id;
-		}
+        // Generate all 'firstName lastName' combinations as data strings
+        for (String f : firstNames) {
+            for (String l : lastNames) {
+                dataStrings.add(f + " " + l);
+            }
+        }
+    }
 
-		@Override
-		public int compareTo(TokenIdPair o) {
-			int cmp = btreeBinCmps[0].compare(baaos.getByteArray(), 0,
-					baaos.getByteArray().length, o.baaos.getByteArray(), 0,
-					o.baaos.getByteArray().length);
-			if (cmp == 0) {
-				return id - o.id;
-			} else {
-				return cmp;
-			}
-		}
-	}
+    private class TokenIdPair implements Comparable<TokenIdPair> {
+        public ByteArrayAccessibleOutputStream baaos = new ByteArrayAccessibleOutputStream();
+        public DataOutputStream dos = new DataOutputStream(baaos);
+        public int id;
 
-	public void loadData() throws IOException, TreeIndexException {
-		List<TokenIdPair> pairs = new ArrayList<TokenIdPair>();
-		// generate pairs for subsequent sorting and bulk-loading
-		int id = 0;
-		for (String s : dataStrings) {
-			ByteArrayAccessibleOutputStream baaos = new ByteArrayAccessibleOutputStream();
-			DataOutputStream dos = new DataOutputStream(baaos);
-			UTF8StringSerializerDeserializer.INSTANCE.serialize(s, dos);
-			tokenizer.reset(baaos.getByteArray(), 0, baaos.size());
-			while (tokenizer.hasNext()) {
-				tokenizer.next();
-				IToken token = tokenizer.getToken();
-				pairs.add(new TokenIdPair(token, id));
-			}
-			++id;
-		}
-		Collections.sort(pairs);
+        TokenIdPair(IToken token, int id) throws IOException {
+            token.serializeToken(dos);
+            this.id = id;
+        }
 
-		// bulk load index
-		IIndexBulkLoadContext ctx = invIndex.beginBulkLoad(BTree.DEFAULT_FILL_FACTOR);
+        @Override
+        public int compareTo(TokenIdPair o) {
+            int cmp = btreeBinCmps[0].compare(baaos.getByteArray(), 0, baaos.getByteArray().length,
+                    o.baaos.getByteArray(), 0, o.baaos.getByteArray().length);
+            if (cmp == 0) {
+                return id - o.id;
+            } else {
+                return cmp;
+            }
+        }
+    }
 
-		for (TokenIdPair t : pairs) {
-			tb.reset();
-			tb.addField(t.baaos.getByteArray(), 0,
-					t.baaos.getByteArray().length);
-			IntegerSerializerDeserializer.INSTANCE.serialize(t.id, tb.getDataOutput());
-			tb.addFieldEndOffset();
-			tuple.reset(tb.getFieldEndOffsets(), tb.getByteArray());
+    public void loadData() throws IOException, TreeIndexException {
+        List<TokenIdPair> pairs = new ArrayList<TokenIdPair>();
+        // generate pairs for subsequent sorting and bulk-loading
+        int id = 0;
+        for (String s : dataStrings) {
+            ByteArrayAccessibleOutputStream baaos = new ByteArrayAccessibleOutputStream();
+            DataOutputStream dos = new DataOutputStream(baaos);
+            UTF8StringSerializerDeserializer.INSTANCE.serialize(s, dos);
+            tokenizer.reset(baaos.getByteArray(), 0, baaos.size());
+            while (tokenizer.hasNext()) {
+                tokenizer.next();
+                IToken token = tokenizer.getToken();
+                pairs.add(new TokenIdPair(token, id));
+            }
+            ++id;
+        }
+        Collections.sort(pairs);
 
-			try {
-				invIndex.bulkLoadAddTuple(tuple, ctx);
-			} catch (Exception e) {
-				e.printStackTrace();
-			}
-		}
-		invIndex.endBulkLoad(ctx);
-	}
+        // bulk load index
+        IIndexBulkLoadContext ctx = invIndex.beginBulkLoad(BTree.DEFAULT_FILL_FACTOR);
 
-	/**
-	 * Runs a specified number of randomly picked strings from dataStrings as
-	 * queries. We run each query, measure it's time, and print it's results.
-	 * 
-	 */
-	private void runQueries(IInvertedIndexSearchModifier searchModifier,
-			int numQueries) throws Exception {
+        for (TokenIdPair t : pairs) {
+            tb.reset();
+            tb.addField(t.baaos.getByteArray(), 0, t.baaos.getByteArray().length);
+            IntegerSerializerDeserializer.INSTANCE.serialize(t.id, tb.getDataOutput());
+            tb.addFieldEndOffset();
+            tuple.reset(tb.getFieldEndOffsets(), tb.getByteArray());
 
-		rnd.setSeed(50);
+            try {
+                invIndex.bulkLoadAddTuple(tuple, ctx);
+            } catch (Exception e) {
+                e.printStackTrace();
+            }
+        }
+        invIndex.endBulkLoad(ctx);
+    }
 
-		InvertedIndexAccessor accessor = (InvertedIndexAccessor) invIndex.createAccessor();
-		InvertedIndexSearchPredicate searchPred = new InvertedIndexSearchPredicate(searchModifier);
-		
-		for (int i = 0; i < numQueries; i++) {
+    /**
+     * Runs a specified number of randomly picked strings from dataStrings as
+     * queries. We run each query, measure it's time, and print it's results.
+     * 
+     */
+    private void runQueries(IInvertedIndexSearchModifier searchModifier, int numQueries) throws Exception {
 
-			int queryIndex = Math.abs(rnd.nextInt() % dataStrings.size());
-			String queryString = dataStrings.get(queryIndex);
+        rnd.setSeed(50);
 
-			// Serialize query.
-			queryTb.reset();
-			UTF8StringSerializerDeserializer.INSTANCE.serialize(queryString,
-					queryTb.getDataOutput());
-			queryTb.addFieldEndOffset();
-			queryTuple.reset(queryTb.getFieldEndOffsets(), queryTb.getByteArray());
+        InvertedIndexAccessor accessor = (InvertedIndexAccessor) invIndex.createAccessor(
+                NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
+        InvertedIndexSearchPredicate searchPred = new InvertedIndexSearchPredicate(searchModifier);
 
-			// Set query tuple in search predicate.
-			searchPred.setQueryTuple(queryTuple);
-			searchPred.setQueryFieldIndex(0);
-			
-			resultCursor = accessor.createSearchCursor();
-			
-			int repeats = 1;
-			double totalTime = 0;
-			for (int j = 0; j < repeats; j++) {
-				long timeStart = System.currentTimeMillis();
-				try {
-					resultCursor.reset();
-					accessor.search(resultCursor, searchPred);
-				} catch (OccurrenceThresholdPanicException e) {
-					// ignore panic queries
-				}
-				long timeEnd = System.currentTimeMillis();
-				totalTime += timeEnd - timeStart;
-			}
-			double avgTime = totalTime / (double) repeats;
-			StringBuilder strBuilder = new StringBuilder();
-			strBuilder.append(i + ": " + "\"" + queryString + "\": " + avgTime
-					+ "ms" + "\n");
-			strBuilder.append("CANDIDATE RESULTS:\n");
-			while (resultCursor.hasNext()) {
-				resultCursor.next();
-				ITupleReference resultTuple = resultCursor.getTuple();
-				int id = IntegerSerializerDeserializer.getInt(
-						resultTuple.getFieldData(0),
-						resultTuple.getFieldStart(0));
-				strBuilder.append(id + " " + dataStrings.get(id));
-				strBuilder.append('\n');
-			}
-			// remove trailing newline
-			strBuilder.deleteCharAt(strBuilder.length() - 1);
-			if (LOGGER.isLoggable(Level.INFO)) {
-				LOGGER.info(strBuilder.toString());
-			}
-		}
-	}
+        for (int i = 0; i < numQueries; i++) {
 
-	/**
-	 * Runs 5 random conjunctive search queries to test the
-	 * ConjunctiveSearchModifier.
-	 * 
-	 */
-	@Test
-	public void conjunctiveQueryTest() throws Exception {
-		IInvertedIndexSearchModifier searchModifier = new ConjunctiveSearchModifier();
-		runQueries(searchModifier, 5);
-	}
+            int queryIndex = Math.abs(rnd.nextInt() % dataStrings.size());
+            String queryString = dataStrings.get(queryIndex);
 
-	/**
-	 * Runs 5 random jaccard-based search queries with thresholds 0.9, 0.8, 0.7.
-	 * Tests the JaccardSearchModifier.
-	 * 
-	 */
-	@Test
-	public void jaccardQueryTest() throws Exception {
-		JaccardSearchModifier searchModifier = new JaccardSearchModifier(1.0f);
+            // Serialize query.
+            queryTb.reset();
+            UTF8StringSerializerDeserializer.INSTANCE.serialize(queryString, queryTb.getDataOutput());
+            queryTb.addFieldEndOffset();
+            queryTuple.reset(queryTb.getFieldEndOffsets(), queryTb.getByteArray());
 
-		if (LOGGER.isLoggable(Level.INFO)) {
-			LOGGER.info("JACCARD: " + 0.9f);
-		}
-		searchModifier.setJaccThresh(0.9f);
-		runQueries(searchModifier, 5);
+            // Set query tuple in search predicate.
+            searchPred.setQueryTuple(queryTuple);
+            searchPred.setQueryFieldIndex(0);
 
-		if (LOGGER.isLoggable(Level.INFO)) {
-			LOGGER.info("JACCARD: " + 0.8f);
-		}
-		searchModifier.setJaccThresh(0.8f);
-		runQueries(searchModifier, 5);
+            resultCursor = accessor.createSearchCursor();
 
-		if (LOGGER.isLoggable(Level.INFO)) {
-			LOGGER.info("JACCARD: " + 0.7f);
-		}
-		searchModifier.setJaccThresh(0.7f);
-		runQueries(searchModifier, 5);
-	}
+            int repeats = 1;
+            double totalTime = 0;
+            for (int j = 0; j < repeats; j++) {
+                long timeStart = System.currentTimeMillis();
+                try {
+                    resultCursor.reset();
+                    accessor.search(resultCursor, searchPred);
+                } catch (OccurrenceThresholdPanicException e) {
+                    // ignore panic queries
+                }
+                long timeEnd = System.currentTimeMillis();
+                totalTime += timeEnd - timeStart;
+            }
+            double avgTime = totalTime / (double) repeats;
+            StringBuilder strBuilder = new StringBuilder();
+            strBuilder.append(i + ": " + "\"" + queryString + "\": " + avgTime + "ms" + "\n");
+            strBuilder.append("CANDIDATE RESULTS:\n");
+            while (resultCursor.hasNext()) {
+                resultCursor.next();
+                ITupleReference resultTuple = resultCursor.getTuple();
+                int id = IntegerSerializerDeserializer
+                        .getInt(resultTuple.getFieldData(0), resultTuple.getFieldStart(0));
+                strBuilder.append(id + " " + dataStrings.get(id));
+                strBuilder.append('\n');
+            }
+            // remove trailing newline
+            strBuilder.deleteCharAt(strBuilder.length() - 1);
+            if (LOGGER.isLoggable(Level.INFO)) {
+                LOGGER.info(strBuilder.toString());
+            }
+        }
+    }
 
-	/**
-	 * Runs 5 random edit-distance based search queries with thresholds 1, 2, 3.
-	 * Tests the EditDistanceSearchModifier.
-	 * 
-	 */
-	@Test
-	public void editDistanceQueryTest() throws Exception {
-		EditDistanceSearchModifier searchModifier = new EditDistanceSearchModifier(
-				3, 0);
+    /**
+     * Runs 5 random conjunctive search queries to test the
+     * ConjunctiveSearchModifier.
+     * 
+     */
+    @Test
+    public void conjunctiveQueryTest() throws Exception {
+        IInvertedIndexSearchModifier searchModifier = new ConjunctiveSearchModifier();
+        runQueries(searchModifier, 5);
+    }
 
-		if (LOGGER.isLoggable(Level.INFO)) {
-			LOGGER.info("EDIT DISTANCE: " + 1);
-		}
-		searchModifier.setEdThresh(1);
-		runQueries(searchModifier, 5);
+    /**
+     * Runs 5 random jaccard-based search queries with thresholds 0.9, 0.8, 0.7.
+     * Tests the JaccardSearchModifier.
+     * 
+     */
+    @Test
+    public void jaccardQueryTest() throws Exception {
+        JaccardSearchModifier searchModifier = new JaccardSearchModifier(1.0f);
 
-		if (LOGGER.isLoggable(Level.INFO)) {
-			LOGGER.info("EDIT DISTANCE: " + 2);
-		}
-		searchModifier.setEdThresh(2);
-		runQueries(searchModifier, 5);
+        if (LOGGER.isLoggable(Level.INFO)) {
+            LOGGER.info("JACCARD: " + 0.9f);
+        }
+        searchModifier.setJaccThresh(0.9f);
+        runQueries(searchModifier, 5);
 
-		if (LOGGER.isLoggable(Level.INFO)) {
-			LOGGER.info("EDIT DISTANCE: " + 3);
-		}
-		searchModifier.setEdThresh(3);
-		runQueries(searchModifier, 5);
-	}
+        if (LOGGER.isLoggable(Level.INFO)) {
+            LOGGER.info("JACCARD: " + 0.8f);
+        }
+        searchModifier.setJaccThresh(0.8f);
+        runQueries(searchModifier, 5);
+
+        if (LOGGER.isLoggable(Level.INFO)) {
+            LOGGER.info("JACCARD: " + 0.7f);
+        }
+        searchModifier.setJaccThresh(0.7f);
+        runQueries(searchModifier, 5);
+    }
+
+    /**
+     * Runs 5 random edit-distance based search queries with thresholds 1, 2, 3.
+     * Tests the EditDistanceSearchModifier.
+     * 
+     */
+    @Test
+    public void editDistanceQueryTest() throws Exception {
+        EditDistanceSearchModifier searchModifier = new EditDistanceSearchModifier(3, 0);
+
+        if (LOGGER.isLoggable(Level.INFO)) {
+            LOGGER.info("EDIT DISTANCE: " + 1);
+        }
+        searchModifier.setEdThresh(1);
+        runQueries(searchModifier, 5);
+
+        if (LOGGER.isLoggable(Level.INFO)) {
+            LOGGER.info("EDIT DISTANCE: " + 2);
+        }
+        searchModifier.setEdThresh(2);
+        runQueries(searchModifier, 5);
+
+        if (LOGGER.isLoggable(Level.INFO)) {
+            LOGGER.info("EDIT DISTANCE: " + 3);
+        }
+        searchModifier.setEdThresh(3);
+        runQueries(searchModifier, 5);
+    }
 }
diff --git a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeExamplesTest.java b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeExamplesTest.java
index 0b2c645..8ebe248 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeExamplesTest.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeExamplesTest.java
@@ -36,10 +36,10 @@
     @Override
     protected ITreeIndex createTreeIndex(ITypeTraits[] typeTraits, IBinaryComparatorFactory[] cmpFactories)
             throws TreeIndexException {
-        return LSMBTreeUtils.createLSMTree(harness.getMemBufferCache(), harness.getMemOpCallback(),
-                harness.getMemFreePageManager(), harness.getIOManager(), harness.getOnDiskDir(),
-                harness.getDiskBufferCache(), harness.getDiskFileMapProvider(), typeTraits, cmpFactories,
-                new ImmediateFlushPolicy(harness.getIOScheduler()), NoMergePolicy.INSTANCE);
+        return LSMBTreeUtils.createLSMTree(harness.getMemBufferCache(), harness.getMemFreePageManager(),
+                harness.getIOManager(), harness.getOnDiskDir(), harness.getDiskBufferCache(),
+                harness.getDiskFileMapProvider(), typeTraits, cmpFactories, new ImmediateFlushPolicy(harness.getIOScheduler()),
+                NoMergePolicy.INSTANCE);
     }
 
     @Override
diff --git a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeMultiThreadTest.java b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeMultiThreadTest.java
index 8dbfd75..81fa29c 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeMultiThreadTest.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeMultiThreadTest.java
@@ -51,10 +51,10 @@
     @Override
     protected ITreeIndex createTreeIndex(ITypeTraits[] typeTraits, IBinaryComparatorFactory[] cmpFactories)
             throws TreeIndexException {
-        return LSMBTreeUtils.createLSMTree(harness.getMemBufferCache(), harness.getMemOpCallback(),
-                harness.getMemFreePageManager(), harness.getIOManager(), harness.getOnDiskDir(),
-                harness.getDiskBufferCache(), harness.getDiskFileMapProvider(), typeTraits, cmpFactories,
-                new ImmediateFlushPolicy(harness.getIOScheduler()), NoMergePolicy.INSTANCE);
+        return LSMBTreeUtils.createLSMTree(harness.getMemBufferCache(), harness.getMemFreePageManager(),
+                harness.getIOManager(), harness.getOnDiskDir(), harness.getDiskBufferCache(),
+                harness.getDiskFileMapProvider(), typeTraits, cmpFactories, new ImmediateFlushPolicy(harness.getIOScheduler()),
+                NoMergePolicy.INSTANCE);
     }
 
     @Override
diff --git a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/BTreeRunner.java b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/BTreeRunner.java
index 2ecd9f8..ed0f373 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/BTreeRunner.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/BTreeRunner.java
@@ -25,7 +25,6 @@
 import edu.uci.ics.hyracks.storage.am.btree.exceptions.BTreeException;
 import edu.uci.ics.hyracks.storage.am.btree.frames.BTreeLeafFrameType;
 import edu.uci.ics.hyracks.storage.am.btree.util.BTreeUtils;
-import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.common.file.IFileMapProvider;
 import edu.uci.ics.hyracks.test.support.TestStorageManagerComponentHolder;
 import edu.uci.ics.hyracks.test.support.TestUtils;
@@ -49,7 +48,6 @@
         bufferCache.createFile(file);
         btreeFileId = fmp.lookupFileId(file);
         bufferCache.openFile(btreeFileId);
-        btree = BTreeUtils.createBTree(bufferCache, NoOpOperationCallback.INSTANCE, typeTraits, cmpFactories,
-                BTreeLeafFrameType.REGULAR_NSM);
+        btree = BTreeUtils.createBTree(bufferCache, typeTraits, cmpFactories, BTreeLeafFrameType.REGULAR_NSM);
     }
 }
diff --git a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/InMemoryBTreeRunner.java b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/InMemoryBTreeRunner.java
index 20520c0..b7f5a7d 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/InMemoryBTreeRunner.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/InMemoryBTreeRunner.java
@@ -44,21 +44,22 @@
 public class InMemoryBTreeRunner extends Thread implements IExperimentRunner {
     protected IBufferCache bufferCache;
     protected int btreeFileId;
-    
+
     protected final static SimpleDateFormat simpleDateFormat = new SimpleDateFormat("ddMMyy-hhmmssSS");
     protected final static String tmpDir = System.getProperty("java.io.tmpdir");
     protected final static String sep = System.getProperty("file.separator");
     protected String fileName;
-    
+
     protected final int numBatches;
-    protected BTree btree;    
-    
-    public InMemoryBTreeRunner(int numBatches, int pageSize, int numPages, ITypeTraits[] typeTraits, IBinaryComparatorFactory[] cmpFactories) throws HyracksDataException, BTreeException {
+    protected BTree btree;
+
+    public InMemoryBTreeRunner(int numBatches, int pageSize, int numPages, ITypeTraits[] typeTraits,
+            IBinaryComparatorFactory[] cmpFactories) throws HyracksDataException, BTreeException {
         this.numBatches = numBatches;
         fileName = tmpDir + sep + simpleDateFormat.format(new Date());
         init(pageSize, numPages, typeTraits, cmpFactories);
     }
-    
+
     protected void init(int pageSize, int numPages, ITypeTraits[] typeTraits, IBinaryComparatorFactory[] cmpFactories)
             throws HyracksDataException, BTreeException {
         ICacheMemoryAllocator allocator = new HeapBufferAllocator();
@@ -70,30 +71,30 @@
         ITreeIndexFrameFactory interiorFrameFactory = new BTreeNSMInteriorFrameFactory(tupleWriterFactory);
         ITreeIndexMetaDataFrameFactory metaFrameFactory = new LIFOMetaDataFrameFactory();
         IFreePageManager freePageManager = new InMemoryFreePageManager(bufferCache.getNumPages(), metaFrameFactory);
-        btree = new BTree(bufferCache, NoOpOperationCallback.INSTANCE, typeTraits.length, cmpFactories,
-                freePageManager, interiorFrameFactory, leafFrameFactory);
+        btree = new BTree(bufferCache, typeTraits.length, cmpFactories, freePageManager, interiorFrameFactory,
+                leafFrameFactory);
     }
 
     @Override
-    public long runExperiment(DataGenThread dataGen, int numThreads) throws Exception {        
+    public long runExperiment(DataGenThread dataGen, int numThreads) throws Exception {
         BTreeThread[] threads = new BTreeThread[numThreads];
         int threadNumBatches = numBatches / numThreads;
-    	for (int i = 0; i < numThreads; i++) {
-    		threads[i] = new BTreeThread(dataGen, btree, threadNumBatches);
-    	}
-    	// Wait until the tupleBatchQueue is completely full.
+        for (int i = 0; i < numThreads; i++) {
+            threads[i] = new BTreeThread(dataGen, btree, threadNumBatches);
+        }
+        // Wait until the tupleBatchQueue is completely full.
         while (dataGen.tupleBatchQueue.remainingCapacity() != 0) {
             Thread.sleep(10);
         }
 
-    	long start = System.currentTimeMillis();
-    	for (int i = 0; i < numThreads; i++) {
-    		threads[i].start();
-    	}
-    	for (int i = 0; i < numThreads; i++) {
-    		threads[i].join();
-    	}
-    	long end = System.currentTimeMillis();
+        long start = System.currentTimeMillis();
+        for (int i = 0; i < numThreads; i++) {
+            threads[i].start();
+        }
+        for (int i = 0; i < numThreads; i++) {
+            threads[i].join();
+        }
+        long end = System.currentTimeMillis();
         long time = end - start;
         return time;
     }
@@ -108,21 +109,22 @@
         bufferCache.close();
     }
 
-	@Override
-	public void reset() throws Exception {
-		btree.create(btreeFileId);		
-	}
-	
-	public class BTreeThread extends Thread {
-    	private final DataGenThread dataGen;
-    	private final int numBatches;
-    	private final ITreeIndexAccessor indexAccessor;
-    	public BTreeThread(DataGenThread dataGen, BTree btree, int numBatches) {
-    		this.dataGen = dataGen;
-    		this.numBatches = numBatches;
-    		indexAccessor = btree.createAccessor();
-    	}
-    	
+    @Override
+    public void reset() throws Exception {
+        btree.create(btreeFileId);
+    }
+
+    public class BTreeThread extends Thread {
+        private final DataGenThread dataGen;
+        private final int numBatches;
+        private final ITreeIndexAccessor indexAccessor;
+
+        public BTreeThread(DataGenThread dataGen, BTree btree, int numBatches) {
+            this.dataGen = dataGen;
+            this.numBatches = numBatches;
+            indexAccessor = btree.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
+        }
+
         @Override
         public void run() {
             try {
@@ -130,7 +132,7 @@
                     TupleBatch batch = dataGen.tupleBatchQueue.take();
                     for (int j = 0; j < batch.size(); j++) {
                         try {
-                        	indexAccessor.insert(batch.get(j));
+                            indexAccessor.insert(batch.get(j));
                         } catch (TreeIndexException e) {
                         }
                     }
diff --git a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/LSMTreeRunner.java b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/LSMTreeRunner.java
index d244af4..38c52ed 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/LSMTreeRunner.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/perf/LSMTreeRunner.java
@@ -84,9 +84,9 @@
         InMemoryFreePageManager memFreePageManager = new InMemoryFreePageManager(inMemNumPages,
                 new LIFOMetaDataFrameFactory());
 
-        lsmtree = LSMBTreeUtils.createLSMTree(memBufferCache, NoOpOperationCallback.INSTANCE, memFreePageManager,
-                ioManager, onDiskDir, bufferCache, fmp, typeTraits, cmpFactories, new ImmediateFlushPolicy(
-                        SequentialScheduler.INSTANCE), NoMergePolicy.INSTANCE);
+        lsmtree = LSMBTreeUtils.createLSMTree(memBufferCache, memFreePageManager, ioManager, onDiskDir, bufferCache,
+                fmp, typeTraits, cmpFactories, new ImmediateFlushPolicy(SequentialScheduler.INSTANCE),
+                NoMergePolicy.INSTANCE);
     }
 
     @Override
@@ -138,7 +138,7 @@
         public LSMTreeThread(DataGenThread dataGen, LSMBTree lsmTree, int numBatches) {
             this.dataGen = dataGen;
             this.numBatches = numBatches;
-            lsmTreeAccessor = lsmTree.createAccessor();
+            lsmTreeAccessor = lsmTree.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
         }
 
         @Override
diff --git a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeTestContext.java b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeTestContext.java
index c59e223..fcc6245 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeTestContext.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeTestContext.java
@@ -25,7 +25,6 @@
 import edu.uci.ics.hyracks.storage.am.btree.OrderedIndexTestContext;
 import edu.uci.ics.hyracks.storage.am.common.CheckTuple;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
-import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.lsm.btree.impls.LSMBTree;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMMergePolicy;
 import edu.uci.ics.hyracks.storage.am.lsm.common.freepage.InMemoryBufferCache;
@@ -68,9 +67,9 @@
             int numKeyFields, int fileId, ILSMMergePolicy mergePolicy) throws Exception {
         ITypeTraits[] typeTraits = SerdeUtils.serdesToTypeTraits(fieldSerdes);
         IBinaryComparatorFactory[] cmpFactories = SerdeUtils.serdesToComparatorFactories(fieldSerdes, numKeyFields);
-        LSMBTree lsmTree = LSMBTreeUtils.createLSMTree(memBufferCache, NoOpOperationCallback.INSTANCE,
-                memFreePageManager, ioManager, onDiskDir, diskBufferCache, diskFileMapProvider, typeTraits,
-                cmpFactories, new ImmediateFlushPolicy(SequentialScheduler.INSTANCE), mergePolicy);
+        LSMBTree lsmTree = LSMBTreeUtils.createLSMTree(memBufferCache, memFreePageManager,
+                ioManager, onDiskDir, diskBufferCache, diskFileMapProvider, typeTraits, cmpFactories,
+                new ImmediateFlushPolicy(SequentialScheduler.INSTANCE), mergePolicy);
         lsmTree.create(fileId);
         lsmTree.open(fileId);
         LSMBTreeTestContext testCtx = new LSMBTreeTestContext(fieldSerdes, lsmTree);
diff --git a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeTestHarness.java b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeTestHarness.java
index 7143448..d514722 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeTestHarness.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/util/LSMBTreeTestHarness.java
@@ -28,9 +28,7 @@
 import edu.uci.ics.hyracks.api.io.IODeviceHandle;
 import edu.uci.ics.hyracks.control.nc.io.IOManager;
 import edu.uci.ics.hyracks.storage.am.btree.frames.BTreeLeafFrameType;
-import edu.uci.ics.hyracks.storage.am.common.api.IOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.frames.LIFOMetaDataFrameFactory;
-import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOScheduler;
 import edu.uci.ics.hyracks.storage.am.lsm.common.freepage.InMemoryBufferCache;
 import edu.uci.ics.hyracks.storage.am.lsm.common.freepage.InMemoryFreePageManager;
@@ -183,10 +181,6 @@
         return rnd;
     }
 
-    public IOperationCallback getMemOpCallback() {
-        return NoOpOperationCallback.INSTANCE;
-    }
-
     public ILSMIOScheduler getIOScheduler() {
         return ioScheduler;
     }
diff --git a/hyracks-tests/hyracks-storage-am-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/rtree/RTreeSearchCursorTest.java b/hyracks-tests/hyracks-storage-am-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/rtree/RTreeSearchCursorTest.java
index 8332c11..9248deb 100644
--- a/hyracks-tests/hyracks-storage-am-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/rtree/RTreeSearchCursorTest.java
+++ b/hyracks-tests/hyracks-storage-am-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/rtree/RTreeSearchCursorTest.java
@@ -41,9 +41,8 @@
 import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
 import edu.uci.ics.hyracks.storage.am.common.frames.LIFOMetaDataFrameFactory;
 import edu.uci.ics.hyracks.storage.am.common.freepage.LinkedListFreePageManager;
+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.rtree.RTreeCheckTuple;
-import edu.uci.ics.hyracks.storage.am.rtree.RTreeTestUtils;
 import edu.uci.ics.hyracks.storage.am.rtree.api.IRTreeInteriorFrame;
 import edu.uci.ics.hyracks.storage.am.rtree.api.IRTreeLeafFrame;
 import edu.uci.ics.hyracks.storage.am.rtree.frames.RTreeNSMInteriorFrameFactory;
@@ -124,7 +123,7 @@
 
         ArrayTupleBuilder tb = new ArrayTupleBuilder(fieldCount);
         ArrayTupleReference tuple = new ArrayTupleReference();
-        ITreeIndexAccessor indexAccessor = rtree.createAccessor();
+        ITreeIndexAccessor indexAccessor = rtree.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
         int numInserts = 10000;
         ArrayList<RTreeCheckTuple> checkTuples = new ArrayList<RTreeCheckTuple>();
         for (int i = 0; i < numInserts; i++) {