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 80e9e9f..7d6e96b 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
@@ -153,7 +153,7 @@
 
         BlockingIOOperationCallback cb = new BlockingIOOperationCallback();
         ILSMIndexAccessor accessor = createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
-        lsmHarness.getIOScheduler().scheduleOperation(accessor.createFlushOperation(cb));
+        accessor.scheduleFlush(cb);
         try {
             cb.waitForIO();
         } catch (InterruptedException e) {
@@ -514,10 +514,11 @@
         }
 
         @Override
-        public ILSMIOOperation createFlushOperation(ILSMIOOperationCallback callback) {
+        public void scheduleFlush(ILSMIOOperationCallback callback) throws HyracksDataException {
             LSMComponentFileReferences componentFileRefs = fileManager.getRelFlushFileReference();
-            return new LSMFlushOperation(lsmHarness.getIndex(), componentFileRefs.getInsertIndexFileReference(),
-                    callback);
+            lsmHarness.getIOScheduler().scheduleOperation(
+                    new LSMFlushOperation(lsmHarness.getIndex(), componentFileRefs.getInsertIndexFileReference(),
+                            callback));
         }
     }
 
diff --git a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMIndexAccessor.java b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMIndexAccessor.java
index 1ad1924..997cc10 100644
--- a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMIndexAccessor.java
+++ b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMIndexAccessor.java
@@ -29,10 +29,9 @@
  * concurrent operations).
  */
 public interface ILSMIndexAccessor extends IIndexAccessor {
-    public ILSMIOOperation createFlushOperation(ILSMIOOperationCallback callback);
+    public void scheduleFlush(ILSMIOOperationCallback callback) throws HyracksDataException;
 
-    public ILSMIOOperation createMergeOperation(ILSMIOOperationCallback callback) throws HyracksDataException,
-            IndexException;
+    public void scheduleMerge(ILSMIOOperationCallback callback) throws HyracksDataException, IndexException;
 
     /**
      * Force a flush of the in-memory component.
@@ -121,7 +120,7 @@
      *             If there is no matching tuple in the index.
      */
     public boolean tryUpsert(ITupleReference tuple) throws HyracksDataException, IndexException;
-    
+
     /**
      * This method can be used to increase the number of 'active' operations of an index artificially,
      * without actually modifying the index.
@@ -132,7 +131,7 @@
      * @throws HyracksDataException
      */
     public boolean tryNoOp() throws HyracksDataException;
-    
+
     /**
      * This method can be used to increase the number of 'active' operations of an index artificially,
      * without actually modifying the index.
diff --git a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/ConstantMergePolicy.java b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/ConstantMergePolicy.java
index 4705566..be7efc4 100644
--- a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/ConstantMergePolicy.java
+++ b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/ConstantMergePolicy.java
@@ -18,7 +18,6 @@
 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.ILSMIOOperation;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperationScheduler;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndex;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexAccessor;
@@ -36,19 +35,12 @@
     }
 
     @Override
-    public void diskComponentAdded(final ILSMIndex index, int totalNumDiskComponents) throws HyracksDataException, IndexException {
+    public void diskComponentAdded(final ILSMIndex index, int totalNumDiskComponents) throws HyracksDataException,
+            IndexException {
         if (totalNumDiskComponents >= threshold) {
             ILSMIndexAccessor accessor = (ILSMIndexAccessor) index.createAccessor(NoOpOperationCallback.INSTANCE,
                     NoOpOperationCallback.INSTANCE);
-            ILSMIOOperation op;
-            try {
-                op = accessor.createMergeOperation(NoOpIOOperationCallback.INSTANCE);
-                if (op != null) {
-                    ioScheduler.scheduleOperation(op);
-                }
-            } catch (LSMMergeInProgressException e) {
-                // Do nothing
-            }
+            accessor.scheduleMerge(NoOpIOOperationCallback.INSTANCE);
         }
     }
 }
diff --git a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMTreeIndexAccessor.java b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMTreeIndexAccessor.java
index d752ab4..e286a7c 100644
--- a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMTreeIndexAccessor.java
+++ b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMTreeIndexAccessor.java
@@ -83,9 +83,9 @@
     @Override
     public boolean tryUpsert(ITupleReference tuple) throws HyracksDataException, IndexException {
         ctx.setOperation(IndexOperation.UPSERT);
-        return lsmHarness.insertUpdateOrDelete(tuple, ctx, true);        
+        return lsmHarness.insertUpdateOrDelete(tuple, ctx, true);
     }
-    
+
     @Override
     public void search(IIndexCursor cursor, ISearchPredicate searchPred) throws HyracksDataException, IndexException {
         ctx.setOperation(IndexOperation.SEARCH);
@@ -109,11 +109,13 @@
     }
 
     @Override
-    public ILSMIOOperation createMergeOperation(ILSMIOOperationCallback callback) throws HyracksDataException,
-            IndexException {
-        return lsmHarness.createMergeOperation(callback);
+    public void scheduleMerge(ILSMIOOperationCallback callback) throws HyracksDataException, IndexException {
+        ILSMIOOperation op = lsmHarness.createMergeOperation(callback);
+        if (op != null) {
+            lsmHarness.getIOScheduler().scheduleOperation(op);
+        }
     }
-    
+
     @Override
     public boolean tryNoOp() throws HyracksDataException {
         return lsmHarness.noOp(ctx, true);
diff --git a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/ReferenceCountingOperationTracker.java b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/ReferenceCountingOperationTracker.java
index a739b46..a162fc1 100644
--- a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/ReferenceCountingOperationTracker.java
+++ b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/ReferenceCountingOperationTracker.java
@@ -59,7 +59,7 @@
         if (index.getFlushStatus(index) && threadRefCount == 0) {
             ILSMIndexAccessor accessor = (ILSMIndexAccessor) index.createAccessor(NoOpOperationCallback.INSTANCE,
                     NoOpOperationCallback.INSTANCE);
-            index.getIOScheduler().scheduleOperation(accessor.createFlushOperation(FLUSHCALLBACK_INSTANCE));
+            accessor.scheduleFlush(FLUSHCALLBACK_INSTANCE);
         }
     }
 
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndex.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndex.java
index 7d8726d..fd8b7e4 100644
--- a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndex.java
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndex.java
@@ -228,7 +228,7 @@
         BlockingIOOperationCallback blockingCallBack = new BlockingIOOperationCallback();
         ILSMIndexAccessor accessor = (ILSMIndexAccessor) createAccessor(NoOpOperationCallback.INSTANCE,
                 NoOpOperationCallback.INSTANCE);
-        lsmHarness.getIOScheduler().scheduleOperation(accessor.createFlushOperation(blockingCallBack));
+        accessor.scheduleFlush(blockingCallBack);
         try {
             blockingCallBack.waitForIO();
         } catch (InterruptedException e) {
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexAccessor.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexAccessor.java
index 5d329a0..069f10d 100644
--- a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexAccessor.java
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/impls/LSMInvertedIndexAccessor.java
@@ -80,11 +80,11 @@
     }
 
     @Override
-    public ILSMIOOperation createFlushOperation(ILSMIOOperationCallback callback) {
+    public void scheduleFlush(ILSMIOOperationCallback callback) throws HyracksDataException {
         LSMComponentFileReferences componentFileRefs = fileManager.getRelFlushFileReference();
-        return new LSMInvertedIndexFlushOperation(lsmHarness.getIndex(),
-                componentFileRefs.getInsertIndexFileReference(), componentFileRefs.getDeleteIndexFileReference(),
-                callback);
+        lsmHarness.getIOScheduler().scheduleOperation(
+                new LSMInvertedIndexFlushOperation(lsmHarness.getIndex(), componentFileRefs
+                        .getInsertIndexFileReference(), componentFileRefs.getDeleteIndexFileReference(), callback));
     }
 
     @Override
@@ -93,9 +93,11 @@
     }
 
     @Override
-    public ILSMIOOperation createMergeOperation(ILSMIOOperationCallback callback) throws HyracksDataException,
-            IndexException {
-        return lsmHarness.createMergeOperation(callback);
+    public void scheduleMerge(ILSMIOOperationCallback callback) throws HyracksDataException, IndexException {
+        ILSMIOOperation op = lsmHarness.createMergeOperation(callback);
+        if (op != null) {
+            lsmHarness.getIOScheduler().scheduleOperation(op);
+        }
     }
 
     @Override
diff --git a/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/AbstractLSMRTree.java b/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/AbstractLSMRTree.java
index 1337e34..440a5a7 100644
--- a/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/AbstractLSMRTree.java
+++ b/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/AbstractLSMRTree.java
@@ -152,7 +152,7 @@
         BlockingIOOperationCallback cb = new BlockingIOOperationCallback();
         ILSMIndexAccessor accessor = (ILSMIndexAccessor) createAccessor(NoOpOperationCallback.INSTANCE,
                 NoOpOperationCallback.INSTANCE);
-        lsmHarness.getIOScheduler().scheduleOperation(accessor.createFlushOperation(cb));
+        accessor.scheduleFlush(cb);
         try {
             cb.waitForIO();
         } catch (InterruptedException 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 e9c965a..e328634 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
@@ -356,10 +356,11 @@
         }
 
         @Override
-        public ILSMIOOperation createFlushOperation(ILSMIOOperationCallback callback) {
+        public void scheduleFlush(ILSMIOOperationCallback callback) throws HyracksDataException {
             LSMComponentFileReferences componentFileRefs = fileManager.getRelFlushFileReference();
-            return new LSMRTreeFlushOperation(lsmHarness.getIndex(), componentFileRefs.getInsertIndexFileReference(),
-                    componentFileRefs.getDeleteIndexFileReference(), callback);
+            lsmHarness.getIOScheduler().scheduleOperation(
+                    new LSMRTreeFlushOperation(lsmHarness.getIndex(), componentFileRefs.getInsertIndexFileReference(),
+                            componentFileRefs.getDeleteIndexFileReference(), callback));
         }
     }
 
diff --git a/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeWithAntiMatterTuples.java b/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeWithAntiMatterTuples.java
index faac6ca..3441bd3 100644
--- a/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeWithAntiMatterTuples.java
+++ b/hyracks-storage-am-lsm-rtree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/impls/LSMRTreeWithAntiMatterTuples.java
@@ -333,10 +333,11 @@
         }
 
         @Override
-        public ILSMIOOperation createFlushOperation(ILSMIOOperationCallback callback) {
+        public void scheduleFlush(ILSMIOOperationCallback callback) throws HyracksDataException {
             LSMComponentFileReferences relFlushFileRefs = fileManager.getRelFlushFileReference();
-            return new LSMFlushOperation(lsmHarness.getIndex(), relFlushFileRefs.getInsertIndexFileReference(),
-                    callback);
+            lsmHarness.getIOScheduler().scheduleOperation(
+                    new LSMFlushOperation(lsmHarness.getIndex(), relFlushFileRefs.getInsertIndexFileReference(),
+                            callback));
         }
     }
 
diff --git a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeMergeTestDriver.java b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeMergeTestDriver.java
index 3add02e..8b02a8e 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeMergeTestDriver.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeMergeTestDriver.java
@@ -24,7 +24,6 @@
 import edu.uci.ics.hyracks.storage.am.btree.OrderedIndexTestUtils;
 import edu.uci.ics.hyracks.storage.am.btree.frames.BTreeLeafFrameType;
 import edu.uci.ics.hyracks.storage.am.config.AccessMethodTestsConfig;
-import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.NoOpIOOperationCallback;
 
@@ -65,10 +64,7 @@
             }
 
             ILSMIndexAccessor accessor = (ILSMIndexAccessor) ctx.getIndexAccessor();
-            ILSMIOOperation ioop = accessor.createMergeOperation(NoOpIOOperationCallback.INSTANCE);
-            if (ioop != null) {
-                accessor.merge(ioop);
-            }
+            accessor.scheduleMerge(NoOpIOOperationCallback.INSTANCE);
 
             orderedIndexTestUtils.checkPointSearches(ctx);
             orderedIndexTestUtils.checkScan(ctx);
diff --git a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeModificationOperationCallbackTest.java b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeModificationOperationCallbackTest.java
index 06857b5..99903bc 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeModificationOperationCallbackTest.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/LSMBTreeModificationOperationCallbackTest.java
@@ -5,11 +5,9 @@
 import edu.uci.ics.hyracks.dataflow.common.util.SerdeUtils;
 import edu.uci.ics.hyracks.dataflow.common.util.TupleUtils;
 import edu.uci.ics.hyracks.storage.am.btree.AbstractModificationOperationCallbackTest;
-import edu.uci.ics.hyracks.storage.am.common.api.IIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.lsm.btree.util.LSMBTreeTestHarness;
 import edu.uci.ics.hyracks.storage.am.lsm.btree.util.LSMBTreeUtils;
-import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.BlockingIOOperationCallback;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.NoOpOperationTrackerFactory;
@@ -49,8 +47,7 @@
 
     @Test
     public void modificationCallbackTest() throws Exception {
-        IIndexAccessor accessor = index.createAccessor(cb, NoOpOperationCallback.INSTANCE);
-        ILSMIOOperation flushOp = ((ILSMIndexAccessor) accessor).createFlushOperation(ioOpCallback);
+        ILSMIndexAccessor accessor = (ILSMIndexAccessor) index.createAccessor(cb, NoOpOperationCallback.INSTANCE);
 
         for (int j = 0; j < 2; j++) {
             isFoundNull = true;
@@ -60,7 +57,7 @@
             }
 
             if (j == 1) {
-                harness.getIOScheduler().scheduleOperation(flushOp);
+                accessor.scheduleFlush(ioOpCallback);
                 ioOpCallback.waitForIO();
                 isFoundNull = true;
             } else {
@@ -73,7 +70,7 @@
             }
 
             if (j == 1) {
-                harness.getIOScheduler().scheduleOperation(flushOp);
+                accessor.scheduleFlush(ioOpCallback);
                 ioOpCallback.waitForIO();
                 isFoundNull = true;
             } else {
@@ -85,7 +82,7 @@
                 accessor.delete(tuple);
             }
 
-            harness.getIOScheduler().scheduleOperation(flushOp);
+            accessor.scheduleFlush(ioOpCallback);
             ioOpCallback.waitForIO();
         }
     }
diff --git a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeTestWorker.java b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeTestWorker.java
index 2dc3d6f..2c22b3a 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeTestWorker.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeTestWorker.java
@@ -33,7 +33,6 @@
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
 import edu.uci.ics.hyracks.storage.am.lsm.btree.impls.LSMBTree;
 import edu.uci.ics.hyracks.storage.am.lsm.btree.impls.LSMBTree.LSMBTreeAccessor;
-import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.LSMMergeInProgressException;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.NoOpIOOperationCallback;
 
@@ -109,10 +108,7 @@
 
             case MERGE:
                 try {
-                    ILSMIOOperation ioop = accessor.createMergeOperation(NoOpIOOperationCallback.INSTANCE);
-                    if (ioop != null) {
-                        accessor.merge(ioop);
-                    }
+                    accessor.scheduleMerge(NoOpIOOperationCallback.INSTANCE);
                 } catch (LSMMergeInProgressException e) {
                     // Ignore ongoing merges. Do an insert instead.
                     try {
diff --git a/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/LSMInvertedIndexMergeTest.java b/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/LSMInvertedIndexMergeTest.java
index 0a65834..811919b 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/LSMInvertedIndexMergeTest.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/LSMInvertedIndexMergeTest.java
@@ -22,7 +22,6 @@
 import edu.uci.ics.hyracks.storage.am.common.datagen.TupleGenerator;
 import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.config.AccessMethodTestsConfig;
-import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.NoOpIOOperationCallback;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.common.AbstractInvertedIndexLoadTest;
@@ -33,7 +32,7 @@
 public class LSMInvertedIndexMergeTest extends AbstractInvertedIndexLoadTest {
 
     private final int maxTreesToMerge = AccessMethodTestsConfig.LSM_INVINDEX_MAX_TREES_TO_MERGE;
-    
+
     public LSMInvertedIndexMergeTest() {
         super(InvertedIndexType.LSM, true, 1);
     }
@@ -41,10 +40,11 @@
     @Override
     protected void runTest(LSMInvertedIndexTestContext testCtx, TupleGenerator tupleGen) throws IOException,
             IndexException {
-        IIndex invIndex = testCtx.getIndex();        
+        IIndex invIndex = testCtx.getIndex();
         invIndex.create();
         invIndex.activate();
-        ILSMIndexAccessor invIndexAccessor = (ILSMIndexAccessor) invIndex.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
+        ILSMIndexAccessor invIndexAccessor = (ILSMIndexAccessor) invIndex.createAccessor(
+                NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
 
         for (int i = 0; i < maxTreesToMerge; i++) {
             for (int j = 0; j < i; j++) {
@@ -55,14 +55,11 @@
                 }
             }
             // Perform merge.
-            ILSMIOOperation ioop = invIndexAccessor.createMergeOperation(NoOpIOOperationCallback.INSTANCE);
-            if (ioop != null) {
-                invIndexAccessor.merge(ioop);
-            }
+            invIndexAccessor.scheduleMerge(NoOpIOOperationCallback.INSTANCE);
             validateAndCheckIndex(testCtx);
             runTinySearchWorkload(testCtx, tupleGen);
         }
-        
+
         invIndex.deactivate();
         invIndex.destroy();
     }
diff --git a/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/PartitionedLSMInvertedIndexMergeTest.java b/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/PartitionedLSMInvertedIndexMergeTest.java
index 52bb3f8..786afe1 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/PartitionedLSMInvertedIndexMergeTest.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/PartitionedLSMInvertedIndexMergeTest.java
@@ -22,7 +22,6 @@
 import edu.uci.ics.hyracks.storage.am.common.datagen.TupleGenerator;
 import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.config.AccessMethodTestsConfig;
-import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.NoOpIOOperationCallback;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.common.AbstractInvertedIndexLoadTest;
@@ -33,7 +32,7 @@
 public class PartitionedLSMInvertedIndexMergeTest extends AbstractInvertedIndexLoadTest {
 
     private final int maxTreesToMerge = AccessMethodTestsConfig.LSM_INVINDEX_MAX_TREES_TO_MERGE;
-    
+
     public PartitionedLSMInvertedIndexMergeTest() {
         super(InvertedIndexType.PARTITIONED_LSM, true, 1);
     }
@@ -41,10 +40,11 @@
     @Override
     protected void runTest(LSMInvertedIndexTestContext testCtx, TupleGenerator tupleGen) throws IOException,
             IndexException {
-        IIndex invIndex = testCtx.getIndex();        
+        IIndex invIndex = testCtx.getIndex();
         invIndex.create();
         invIndex.activate();
-        ILSMIndexAccessor invIndexAccessor = (ILSMIndexAccessor) invIndex.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
+        ILSMIndexAccessor invIndexAccessor = (ILSMIndexAccessor) invIndex.createAccessor(
+                NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
 
         for (int i = 0; i < maxTreesToMerge; i++) {
             for (int j = 0; j < i; j++) {
@@ -55,14 +55,11 @@
                 }
             }
             // Perform merge.
-            ILSMIOOperation ioop = invIndexAccessor.createMergeOperation(NoOpIOOperationCallback.INSTANCE);
-            if (ioop != null) {
-                invIndexAccessor.merge(ioop);
-            }
+            invIndexAccessor.scheduleMerge(NoOpIOOperationCallback.INSTANCE);
             validateAndCheckIndex(testCtx);
             runTinySearchWorkload(testCtx, tupleGen);
         }
-        
+
         invIndex.deactivate();
         invIndex.destroy();
     }
diff --git a/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/multithread/LSMInvertedIndexTestWorker.java b/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/multithread/LSMInvertedIndexTestWorker.java
index 0269c58..8f61449 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/multithread/LSMInvertedIndexTestWorker.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/multithread/LSMInvertedIndexTestWorker.java
@@ -30,7 +30,6 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexCursor;
 import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
 import edu.uci.ics.hyracks.storage.am.common.datagen.DataGenThread;
-import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.LSMMergeInProgressException;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.NoOpIOOperationCallback;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedIndexSearchModifier;
@@ -45,12 +44,12 @@
 public class LSMInvertedIndexTestWorker extends AbstractIndexTestWorker {
 
     protected final LSMInvertedIndex invIndex;
-    protected final List<ITupleReference> documentCorpus = new ArrayList<ITupleReference>();    
+    protected final List<ITupleReference> documentCorpus = new ArrayList<ITupleReference>();
     protected final Random rnd = new Random(50);
-    
+
     protected final IInvertedIndexSearchModifier[] TEST_SEARCH_MODIFIERS = new IInvertedIndexSearchModifier[] {
             new ConjunctiveSearchModifier(), new JaccardSearchModifier(0.8f), new JaccardSearchModifier(0.5f) };
-    
+
     public LSMInvertedIndexTestWorker(DataGenThread dataGen, TestOperationSelector opSelector, IIndex index,
             int numBatches) {
         super(dataGen, opSelector, index, numBatches);
@@ -67,7 +66,7 @@
         int searchModifierIndex = Math.abs(rnd.nextInt()) % TEST_SEARCH_MODIFIERS.length;
         InvertedIndexSearchPredicate searchPred = new InvertedIndexSearchPredicate(tokenizerFactory.createTokenizer(),
                 TEST_SEARCH_MODIFIERS[searchModifierIndex]);
-        
+
         switch (op) {
             case INSERT: {
                 insert(accessor, tuple);
@@ -99,7 +98,7 @@
                     consumeCursorTuples(searchCursor);
                 } catch (OccurrenceThresholdPanicException e) {
                     // Ignore.
-                }                
+                }
                 break;
             }
 
@@ -112,10 +111,7 @@
 
             case MERGE: {
                 try {
-                    ILSMIOOperation ioop = accessor.createMergeOperation(NoOpIOOperationCallback.INSTANCE);
-                    if (ioop != null) {
-                        accessor.merge(ioop);
-                    }
+                    accessor.scheduleMerge(NoOpIOOperationCallback.INSTANCE);
                 } catch (LSMMergeInProgressException e) {
                     insert(accessor, tuple);
                 }
@@ -126,8 +122,9 @@
                 throw new HyracksDataException("Op " + op.toString() + " not supported.");
         }
     }
-    
-    private void insert(LSMInvertedIndexAccessor accessor, ITupleReference tuple) throws HyracksDataException, IndexException {
+
+    private void insert(LSMInvertedIndexAccessor accessor, ITupleReference tuple) throws HyracksDataException,
+            IndexException {
         // Ignore ongoing merges. Do an insert instead.
         accessor.insert(tuple);
         // Add tuple to document corpus so we can delete it.
diff --git a/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/LSMRTreeMergeTestDriver.java b/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/LSMRTreeMergeTestDriver.java
index 36c3c5c..f272942 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/LSMRTreeMergeTestDriver.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/LSMRTreeMergeTestDriver.java
@@ -21,7 +21,6 @@
 import edu.uci.ics.hyracks.dataflow.common.data.marshalling.IntegerSerializerDeserializer;
 import edu.uci.ics.hyracks.storage.am.common.api.IPrimitiveValueProviderFactory;
 import edu.uci.ics.hyracks.storage.am.config.AccessMethodTestsConfig;
-import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexAccessor;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.NoOpIOOperationCallback;
 import edu.uci.ics.hyracks.storage.am.rtree.AbstractRTreeTestContext;
@@ -67,10 +66,7 @@
             }
 
             ILSMIndexAccessor accessor = (ILSMIndexAccessor) ctx.getIndexAccessor();
-            ILSMIOOperation mergeOperation = accessor.createMergeOperation(NoOpIOOperationCallback.INSTANCE);
-            if (mergeOperation != null) {
-                accessor.merge(mergeOperation);
-            }
+            accessor.scheduleMerge(NoOpIOOperationCallback.INSTANCE);
 
             rTreeTestUtils.checkScan(ctx);
             rTreeTestUtils.checkDiskOrderScan(ctx);
diff --git a/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeTestWorker.java b/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeTestWorker.java
index 12e3ce8..c8f49ab 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeTestWorker.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeTestWorker.java
@@ -27,7 +27,6 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
 import edu.uci.ics.hyracks.storage.am.common.datagen.DataGenThread;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
-import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.LSMMergeInProgressException;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.NoOpIOOperationCallback;
 import edu.uci.ics.hyracks.storage.am.lsm.rtree.impls.LSMRTree;
@@ -75,10 +74,7 @@
 
             case MERGE:
                 try {
-                    ILSMIOOperation mergeOperation = accessor.createMergeOperation(NoOpIOOperationCallback.INSTANCE);
-                    if (mergeOperation != null) {
-                        accessor.merge(mergeOperation);
-                    }
+                    accessor.scheduleMerge(NoOpIOOperationCallback.INSTANCE);
                 } catch (LSMMergeInProgressException e) {
                     // Ignore ongoing merges. Do an insert instead.
                     rearrangeTuple(tuple, cmp);
diff --git a/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeWithAntiMatterTuplesTestWorker.java b/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeWithAntiMatterTuplesTestWorker.java
index 5f88020..5f233fa 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeWithAntiMatterTuplesTestWorker.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeWithAntiMatterTuplesTestWorker.java
@@ -24,7 +24,6 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
 import edu.uci.ics.hyracks.storage.am.common.datagen.DataGenThread;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
-import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIOOperation;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.LSMMergeInProgressException;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.NoOpIOOperationCallback;
 import edu.uci.ics.hyracks.storage.am.lsm.rtree.impls.LSMRTreeWithAntiMatterTuples.LSMRTreeWithAntiMatterTuplesAccessor;
@@ -64,10 +63,7 @@
 
             case MERGE:
                 try {
-                    ILSMIOOperation mergeOperation = accessor.createMergeOperation(NoOpIOOperationCallback.INSTANCE);
-                    if (mergeOperation != null) {
-                        accessor.merge(mergeOperation);
-                    }
+                    accessor.scheduleMerge(NoOpIOOperationCallback.INSTANCE);
                 } catch (LSMMergeInProgressException e) {
                     // Ignore ongoing merges. Do an insert instead.
                     rearrangeTuple(tuple, cmp);