diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/PrimaryIndexSearchOperationCallback.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/PrimaryIndexSearchOperationCallback.java
index 9957edf..8de7ca5 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/PrimaryIndexSearchOperationCallback.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/opcallbacks/PrimaryIndexSearchOperationCallback.java
@@ -36,9 +36,8 @@
 
     @Override
     public boolean proceed(ITupleReference tuple) throws HyracksDataException {
-        int pkHash = computePrimaryKeyHashValue(tuple, primaryKeyFields);
         try {
-            return lockManager.tryLock(datasetId, pkHash, LockMode.S, txnCtx);
+            return lockManager.tryLock(datasetId, -1, LockMode.S, txnCtx);
         } catch (ACIDException e) {
             throw new HyracksDataException(e);
         }
@@ -46,9 +45,8 @@
 
     @Override
     public void reconcile(ITupleReference tuple) throws HyracksDataException {
-        int pkHash = computePrimaryKeyHashValue(tuple, primaryKeyFields);
         try {
-            lockManager.lock(datasetId, pkHash, LockMode.S, txnCtx);
+            lockManager.lock(datasetId, -1, LockMode.S, txnCtx);
         } catch (ACIDException e) {
             throw new HyracksDataException(e);
         }
@@ -56,12 +54,7 @@
 
     @Override
     public void cancel(ITupleReference tuple) throws HyracksDataException {
-        int pkHash = computePrimaryKeyHashValue(tuple, primaryKeyFields);
-        try {
-            lockManager.unlock(datasetId, pkHash, LockMode.S, txnCtx);
-        } catch (ACIDException e) {
-            throw new HyracksDataException(e);
-        }
+        //no op
     }
 
     @Override
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/ConcurrentLockManager.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/ConcurrentLockManager.java
index ddf409e..915271d 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/ConcurrentLockManager.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/ConcurrentLockManager.java
@@ -116,11 +116,10 @@
         final int jobId = txnContext.getJobId().getId();
         
         if (entityHashValue != -1) {
-            // get the intention lock on the dataset, if we want to lock an individual item
-            final byte dsLockMode = LockMode.intentionMode(lockMode);
-            if (! dsLockCache.get().contains(jobId, dsId, dsLockMode)) {
-                lock(datasetId, -1, dsLockMode, txnContext);
-                dsLockCache.get().put(jobId, dsId, dsLockMode);
+            lock(datasetId, -1, LockMode.intentionMode(lockMode), txnContext);
+        } else {
+            if (dsLockCache.get().contains(jobId, dsId, lockMode)) {
+                return;
             }
         }
 
@@ -153,6 +152,9 @@
                         throw new IllegalStateException();
                 }
             }
+            if (entityHashValue == -1) {
+                dsLockCache.get().put(jobId, dsId, lockMode);
+            }
         } finally {
             group.releaseLatch();
         }
@@ -218,12 +220,9 @@
         final int jobId = txnContext.getJobId().getId();
         
         if (entityHashValue != -1) {
-            // get the intention lock on the dataset, if we want to lock an individual item
-            final byte dsLockMode = LockMode.intentionMode(lockMode);
-            if (! dsLockCache.get().contains(jobId, dsId, dsLockMode)) {
-                lock(datasetId, -1, dsLockMode, txnContext);
-                dsLockCache.get().put(jobId, dsId, dsLockMode);
-            }
+            lock(datasetId, -1, LockMode.intentionMode(lockMode), txnContext);
+        } else {
+            throw new UnsupportedOperationException("instant locks are not supported on datasets");
         }
 
         final ResourceGroup group = table.get(dsId, entityHashValue);
@@ -287,13 +286,12 @@
         final int jobId = txnContext.getJobId().getId();
 
         if (entityHashValue != -1) {
-            // get the intention lock on the dataset, if we want to lock an individual item
-            final byte dsLockMode = LockMode.intentionMode(lockMode);
-            if (! dsLockCache.get().contains(jobId, dsId, dsLockMode)) {
-                if (! tryLock(datasetId, -1, dsLockMode, txnContext)) {
-                    return false;
-                }
-                dsLockCache.get().put(jobId, dsId, dsLockMode);
+            if (! tryLock(datasetId, -1, LockMode.intentionMode(lockMode), txnContext)) {
+                return false;
+            }
+        } else {
+            if (dsLockCache.get().contains(jobId, dsId, lockMode)) {
+                return true;
             }
         }
 
@@ -307,7 +305,7 @@
 
             final long resSlot = findOrAllocResourceSlot(group, dsId, entityHashValue);
             final long reqSlot = allocRequestSlot(resSlot, jobSlot, lockMode);
-            
+
             final LockAction act = determineLockAction(resSlot, jobSlot, lockMode);
             switch (act) {
                 case UPD:
@@ -315,6 +313,9 @@
                     // no break
                 case GET:
                     addHolder(reqSlot, resSlot, jobSlot);
+                    if (entityHashValue == -1) {
+                        dsLockCache.get().put(jobId, dsId, lockMode);
+                    }
                     return true;
                 case WAIT:
                 case CONV:
@@ -325,7 +326,7 @@
         } finally {
             group.releaseLatch();
         }
-        
+
         // if we did acquire the dataset lock, but not the entity lock, we keep
         // it anyway and clean it up at the end of the job
     }
@@ -340,14 +341,11 @@
         final int jobId = txnContext.getJobId().getId();
 
         if (entityHashValue != -1) {
-            // get the intention lock on the dataset, if we want to lock an individual item
-            final byte dsLockMode = LockMode.intentionMode(lockMode);
-            if (! dsLockCache.get().contains(jobId, dsId, dsLockMode)) {
-                if (! tryLock(datasetId, -1, dsLockMode, txnContext)) {
-                    return false;
-                }
-                dsLockCache.get().put(jobId, dsId, dsLockMode);
+            if (! tryLock(datasetId, -1, LockMode.intentionMode(lockMode), txnContext)) {
+                return false;
             }
+        } else {
+            throw new UnsupportedOperationException("instant locks are not supported on datasets");
         }
 
         final ResourceGroup group = table.get(dsId, entityHashValue);