diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/IndexBulkLoadOperatorNodePushable.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/IndexBulkLoadOperatorNodePushable.java
index 6251d69..de4e627 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/IndexBulkLoadOperatorNodePushable.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/dataflow/IndexBulkLoadOperatorNodePushable.java
@@ -92,6 +92,5 @@
 
     @Override
     public void fail() throws HyracksDataException {
-        writer.fail();
     }
 }
\ No newline at end of file
diff --git a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMHarness.java b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMHarness.java
index 1c70af5..9c08645 100644
--- a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMHarness.java
+++ b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMHarness.java
@@ -25,8 +25,8 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
 
 public interface ILSMHarness {
-    public void insertUpdateOrDelete(ITupleReference tuple, ILSMIndexOperationContext ictx) throws HyracksDataException,
-            IndexException;
+    public boolean insertUpdateOrDelete(ITupleReference tuple, ILSMIndexOperationContext ictx, boolean tryOperation)
+            throws HyracksDataException, IndexException;
 
     public List<Object> search(IIndexCursor cursor, ISearchPredicate pred, ILSMIndexOperationContext ctx,
             boolean includeMemComponent) throws HyracksDataException, IndexException;
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 a5ef536..c6564b4 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
@@ -32,7 +32,7 @@
     public ILSMIOOperation createFlushOperation(ILSMIOOperationCallback callback);
 
     public ILSMIOOperation createMergeOperation(ILSMIOOperationCallback callback) throws HyracksDataException,
-           IndexException;
+            IndexException;
 
     /**
      * Force a flush of the in-memory component.
@@ -57,4 +57,68 @@
      * @throws IndexException
      */
     public void physicalDelete(ITupleReference tuple) throws HyracksDataException, IndexException;
+
+    /**
+     * Attempts to insert the given tuple.
+     * If the insert would have to wait for a flush to complete, then this method returns false to
+     * allow the caller to avoid potential deadlock situations.
+     * Otherwise, returns true (insert was successful).
+     * 
+     * @param tuple
+     *            Tuple to be inserted.
+     * @throws HyracksDataException
+     *             If the BufferCache throws while un/pinning or un/latching.
+     * @throws IndexException
+     *             If an index-specific constraint is violated, e.g., the key
+     *             already exists.
+     */
+    public boolean tryInsert(ITupleReference tuple) throws HyracksDataException, IndexException;
+
+    /**
+     * Attempts to delete the given tuple.
+     * If the delete would have to wait for a flush to complete, then this method returns false to
+     * allow the caller to avoid potential deadlock situations.
+     * Otherwise, returns true (delete was successful).
+     * 
+     * @param tuple
+     *            Tuple to be deleted.
+     * @throws HyracksDataException
+     *             If the BufferCache throws while un/pinning or un/latching.
+     * @throws IndexException
+     *             If there is no matching tuple in the index.
+     */
+    public boolean tryDelete(ITupleReference tuple) throws HyracksDataException, IndexException;
+
+    /**
+     * Attempts to update the given tuple.
+     * If the update would have to wait for a flush to complete, then this method returns false to
+     * allow the caller to avoid potential deadlock situations.
+     * Otherwise, returns true (update was successful).
+     * 
+     * @param tuple
+     *            Tuple whose match in the index is to be update with the given
+     *            tuples contents.
+     * @throws HyracksDataException
+     *             If the BufferCache throws while un/pinning or un/latching.
+     * @throws IndexException
+     *             If there is no matching tuple in the index.
+     */
+    public boolean tryUpdate(ITupleReference tuple) throws HyracksDataException, IndexException;
+
+    /**
+     * This operation is only supported by indexes with the notion of a unique key.
+     * If tuple's key already exists, then this operation attempts to performs an update.
+     * Otherwise, it attempts to perform an insert.
+     * If the operation would have to wait for a flush to complete, then this method returns false to
+     * allow the caller to avoid potential deadlock situations.
+     * Otherwise, returns true (insert/update was successful).
+     * 
+     * @param tuple
+     *            Tuple to be deleted.
+     * @throws HyracksDataException
+     *             If the BufferCache throws while un/pinning or un/latching.
+     * @throws IndexException
+     *             If there is no matching tuple in the index.
+     */
+    public boolean tryUpsert(ITupleReference tuple) throws HyracksDataException, IndexException;
 }
diff --git a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMOperationTracker.java b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMOperationTracker.java
index 6c5e1a1..1635647 100644
--- a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMOperationTracker.java
+++ b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMOperationTracker.java
@@ -15,9 +15,11 @@
     /**
      * An {@link ILSMIndex} will call this method before an operation enters it,
      * i.e., before any latches are taken.
-     * After this method has been called, the operation is considered 'active'.
+     * If tryOperation is true, and the operation would have to wait for a flush,
+     * then this method does not block and returns false.
+     * Otherwise, this method returns true, and the operation is considered 'active' in the index.
      */
-    public void beforeOperation(ILSMIndexOperationContext opCtx) throws HyracksDataException;
+    public boolean beforeOperation(ILSMIndexOperationContext opCtx, boolean tryOperation) throws HyracksDataException;
 
     /**
      * An {@link ILSMIndex} will call this method after an operation has left the index,
diff --git a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMHarness.java b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMHarness.java
index 634800a..c4ac36e 100644
--- a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMHarness.java
+++ b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/LSMHarness.java
@@ -89,9 +89,12 @@
         opTracker.afterOperation(opCtx);
     }
 
-    public void insertUpdateOrDelete(ITupleReference tuple, ILSMIndexOperationContext ctx) throws HyracksDataException,
-            IndexException {
-        opTracker.beforeOperation(ctx);
+    @Override
+    public boolean insertUpdateOrDelete(ITupleReference tuple, ILSMIndexOperationContext ctx, boolean tryOperation)
+            throws HyracksDataException, IndexException {
+        if (!opTracker.beforeOperation(ctx, tryOperation)) {
+            return false;
+        }
         // It is possible, due to concurrent execution of operations, that an operation will 
         // fail. In such a case, simply retry the operation. Refer to the specific LSMIndex code 
         // to see exactly why an operation might fail.
@@ -100,6 +103,7 @@
         } finally {
             threadExit(ctx);
         }
+        return true;
     }
 
     public void flush(ILSMIOOperation operation) throws HyracksDataException, IndexException {
@@ -135,7 +139,7 @@
         // If the search doesn't include the in-memory component, then we don't have
         // to synchronize with a flush.
         if (includeMemComponent) {
-            opTracker.beforeOperation(ctx);
+            opTracker.beforeOperation(ctx, true);
         }
 
         // Get a snapshot of the current on-disk Trees.
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 a4267d2..fd0d704 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
@@ -39,29 +39,54 @@
     @Override
     public void insert(ITupleReference tuple) throws HyracksDataException, IndexException {
         ctx.setOperation(IndexOperation.INSERT);
-        lsmHarness.insertUpdateOrDelete(tuple, ctx);
+        lsmHarness.insertUpdateOrDelete(tuple, ctx, false);
     }
 
     @Override
     public void update(ITupleReference tuple) throws HyracksDataException, IndexException {
         // Update is the same as insert.
         ctx.setOperation(IndexOperation.UPDATE);
-        lsmHarness.insertUpdateOrDelete(tuple, ctx);
+        lsmHarness.insertUpdateOrDelete(tuple, ctx, false);
     }
 
     @Override
     public void delete(ITupleReference tuple) throws HyracksDataException, IndexException {
         ctx.setOperation(IndexOperation.DELETE);
-        lsmHarness.insertUpdateOrDelete(tuple, ctx);
+        lsmHarness.insertUpdateOrDelete(tuple, ctx, false);
     }
 
     @Override
     public void upsert(ITupleReference tuple) throws HyracksDataException, IndexException {
         ctx.setOperation(IndexOperation.UPSERT);
-        lsmHarness.insertUpdateOrDelete(tuple, ctx);
+        lsmHarness.insertUpdateOrDelete(tuple, ctx, false);
     }
 
     @Override
+    public boolean tryInsert(ITupleReference tuple) throws HyracksDataException, IndexException {
+        ctx.setOperation(IndexOperation.INSERT);
+        return lsmHarness.insertUpdateOrDelete(tuple, ctx, true);
+    }
+
+    @Override
+    public boolean tryDelete(ITupleReference tuple) throws HyracksDataException, IndexException {
+        ctx.setOperation(IndexOperation.DELETE);
+        return lsmHarness.insertUpdateOrDelete(tuple, ctx, true);
+    }
+
+    @Override
+    public boolean tryUpdate(ITupleReference tuple) throws HyracksDataException, IndexException {
+        // Update is the same as insert.
+        ctx.setOperation(IndexOperation.UPDATE);
+        return lsmHarness.insertUpdateOrDelete(tuple, ctx, true);
+    }
+
+    @Override
+    public boolean tryUpsert(ITupleReference tuple) throws HyracksDataException, IndexException {
+        ctx.setOperation(IndexOperation.UPSERT);
+        return lsmHarness.insertUpdateOrDelete(tuple, ctx, true);        
+    }
+    
+    @Override
     public void search(IIndexCursor cursor, ISearchPredicate searchPred) throws HyracksDataException, IndexException {
         ctx.setOperation(IndexOperation.SEARCH);
         lsmHarness.search(cursor, searchPred, ctx, true);
@@ -80,7 +105,7 @@
     @Override
     public void physicalDelete(ITupleReference tuple) throws HyracksDataException, IndexException {
         ctx.setOperation(IndexOperation.PHYSICALDELETE);
-        lsmHarness.insertUpdateOrDelete(tuple, ctx);
+        lsmHarness.insertUpdateOrDelete(tuple, ctx, false);
     }
 
     @Override
diff --git a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/NoOpOperationTrackerFactory.java b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/NoOpOperationTrackerFactory.java
index 00dc66d..f8a8a28 100644
--- a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/NoOpOperationTrackerFactory.java
+++ b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/impls/NoOpOperationTrackerFactory.java
@@ -16,7 +16,7 @@
     private static final long serialVersionUID = 1L;
 
     public static NoOpOperationTrackerFactory INSTANCE = new NoOpOperationTrackerFactory();
-    
+
     @Override
     public ILSMOperationTracker createOperationTracker(ILSMIndex index) {
         return new ILSMOperationTracker() {
@@ -27,8 +27,10 @@
             }
 
             @Override
-            public void beforeOperation(ILSMIndexOperationContext opCtx) throws HyracksDataException {
-                // Do nothing.                        
+            public boolean beforeOperation(ILSMIndexOperationContext opCtx, boolean tryOperation)
+                    throws HyracksDataException {
+                // Do nothing.
+                return true;
             }
 
             @Override
@@ -37,9 +39,9 @@
             }
         };
     }
-    
+
     // Enforce singleton.
     private NoOpOperationTrackerFactory() {
     }
-    
+
 };
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 5b10ba3..b77a97e 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
@@ -20,11 +20,15 @@
     }
 
     @Override
-    public synchronized void beforeOperation(ILSMIndexOperationContext opCtx) throws HyracksDataException {
+    public synchronized boolean beforeOperation(ILSMIndexOperationContext opCtx, boolean tryOperation)
+            throws HyracksDataException {
         // Wait for pending flushes to complete.
         // If flushFlag is set, then the flush is queued to occur by the last exiting thread.
         // This operation should wait for that flush to occur before proceeding.
         if (index.getFlushController().getFlushStatus(index)) {
+            if (tryOperation) {
+                return false;
+            }
             try {
                 this.wait();
             } catch (InterruptedException e) {
@@ -32,6 +36,7 @@
             }
         }
         threadRefCount++;
+        return true;
     }
 
     @Override
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 2e78744..45d21e9 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
@@ -50,13 +50,25 @@
     @Override
     public void insert(ITupleReference tuple) throws HyracksDataException, IndexException {
         ctx.setOperation(IndexOperation.INSERT);
-        lsmHarness.insertUpdateOrDelete(tuple, ctx);
+        lsmHarness.insertUpdateOrDelete(tuple, ctx, false);
     }
 
     @Override
     public void delete(ITupleReference tuple) throws HyracksDataException, IndexException {
         ctx.setOperation(IndexOperation.DELETE);
-        lsmHarness.insertUpdateOrDelete(tuple, ctx);
+        lsmHarness.insertUpdateOrDelete(tuple, ctx, false);
+    }
+
+    @Override
+    public boolean tryInsert(ITupleReference tuple) throws HyracksDataException, IndexException {
+        ctx.setOperation(IndexOperation.INSERT);
+        return lsmHarness.insertUpdateOrDelete(tuple, ctx, true);
+    }
+
+    @Override
+    public boolean tryDelete(ITupleReference tuple) throws HyracksDataException, IndexException {
+        ctx.setOperation(IndexOperation.DELETE);
+        return lsmHarness.insertUpdateOrDelete(tuple, ctx, true);
     }
 
     public void search(IIndexCursor cursor, ISearchPredicate searchPred) throws HyracksDataException, IndexException {
@@ -122,6 +134,16 @@
     }
 
     @Override
+    public boolean tryUpdate(ITupleReference tuple) throws HyracksDataException, IndexException {
+        throw new UnsupportedOperationException("Update not supported by lsm inverted index.");
+    }
+
+    @Override
+    public boolean tryUpsert(ITupleReference tuple) throws HyracksDataException, IndexException {
+        throw new UnsupportedOperationException("Upsert not supported by lsm inverted index.");
+    }
+
+    @Override
     public IInvertedListCursor createInvertedListCursor() {
         throw new UnsupportedOperationException("Cannot create inverted list cursor on lsm inverted index.");
     }