diff --git a/asterix-app/src/test/resources/optimizerts/results/scan-delete-rtree-secondary-index.plan b/asterix-app/src/test/resources/optimizerts/results/scan-delete-rtree-secondary-index.plan
index bf8978b..4f0d931 100644
--- a/asterix-app/src/test/resources/optimizerts/results/scan-delete-rtree-secondary-index.plan
+++ b/asterix-app/src/test/resources/optimizerts/results/scan-delete-rtree-secondary-index.plan
@@ -3,23 +3,21 @@
     -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
       -- INDEX_INSERT_DELETE  |PARTITIONED|
         -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-          -- STABLE_SORT [$$29(ASC), $$30(ASC), $$31(ASC), $$32(ASC)]  |PARTITIONED|
-            -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+          -- STREAM_PROJECT  |PARTITIONED|
+            -- ASSIGN  |PARTITIONED|
               -- STREAM_PROJECT  |PARTITIONED|
                 -- ASSIGN  |PARTITIONED|
-                  -- STREAM_PROJECT  |PARTITIONED|
-                    -- ASSIGN  |PARTITIONED|
+                  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                    -- INSERT_DELETE  |PARTITIONED|
                       -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                        -- INSERT_DELETE  |PARTITIONED|
-                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                            -- STABLE_SORT [$$14(ASC)]  |PARTITIONED|
-                              -- HASH_PARTITION_EXCHANGE [$$14]  |PARTITIONED|
+                        -- STABLE_SORT [$$14(ASC)]  |PARTITIONED|
+                          -- HASH_PARTITION_EXCHANGE [$$14]  |PARTITIONED|
+                            -- ASSIGN  |PARTITIONED|
+                              -- STREAM_PROJECT  |PARTITIONED|
                                 -- ASSIGN  |PARTITIONED|
                                   -- STREAM_PROJECT  |PARTITIONED|
-                                    -- ASSIGN  |PARTITIONED|
-                                      -- STREAM_PROJECT  |PARTITIONED|
+                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                      -- BTREE_SEARCH  |PARTITIONED|
                                         -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                          -- BTREE_SEARCH  |PARTITIONED|
-                                            -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                              -- ASSIGN  |PARTITIONED|
-                                                -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+                                          -- ASSIGN  |PARTITIONED|
+                                            -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/optimizerts/results/scan-insert-secondary-index.plan b/asterix-app/src/test/resources/optimizerts/results/scan-insert-secondary-index.plan
index e6cf237..1458c66 100644
--- a/asterix-app/src/test/resources/optimizerts/results/scan-insert-secondary-index.plan
+++ b/asterix-app/src/test/resources/optimizerts/results/scan-insert-secondary-index.plan
@@ -3,28 +3,24 @@
     -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
       -- INDEX_INSERT_DELETE  |PARTITIONED|
         -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-          -- STABLE_SORT [$$11(ASC)]  |PARTITIONED|
-            -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+          -- STREAM_PROJECT  |PARTITIONED|
+            -- ASSIGN  |PARTITIONED|
               -- STREAM_PROJECT  |PARTITIONED|
-                -- ASSIGN  |PARTITIONED|
-                  -- STREAM_PROJECT  |PARTITIONED|
+                -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                  -- INDEX_INSERT_DELETE  |PARTITIONED|
                     -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                      -- INDEX_INSERT_DELETE  |PARTITIONED|
+                      -- ASSIGN  |PARTITIONED|
                         -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                          -- STABLE_SORT [$$10(ASC)]  |PARTITIONED|
+                          -- INSERT_DELETE  |PARTITIONED|
                             -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                              -- ASSIGN  |PARTITIONED|
-                                -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                  -- INSERT_DELETE  |PARTITIONED|
-                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                      -- STABLE_SORT [$$6(ASC)]  |PARTITIONED|
-                                        -- HASH_PARTITION_EXCHANGE [$$6]  |PARTITIONED|
+                              -- STABLE_SORT [$$6(ASC)]  |PARTITIONED|
+                                -- HASH_PARTITION_EXCHANGE [$$6]  |PARTITIONED|
+                                  -- ASSIGN  |PARTITIONED|
+                                    -- STREAM_PROJECT  |PARTITIONED|
+                                      -- ASSIGN  |PARTITIONED|
+                                        -- STREAM_PROJECT  |PARTITIONED|
                                           -- ASSIGN  |PARTITIONED|
-                                            -- STREAM_PROJECT  |PARTITIONED|
-                                              -- ASSIGN  |PARTITIONED|
-                                                -- STREAM_PROJECT  |PARTITIONED|
-                                                  -- ASSIGN  |PARTITIONED|
-                                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                      -- DATASOURCE_SCAN  |PARTITIONED|
-                                                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                          -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
+                                            -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                              -- DATASOURCE_SCAN  |PARTITIONED|
+                                                -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                  -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterix-installer/src/main/java/edu/uci/ics/asterix/installer/events/PatternCreator.java b/asterix-installer/src/main/java/edu/uci/ics/asterix/installer/events/PatternCreator.java
index 4216978..0f382f9 100644
--- a/asterix-installer/src/main/java/edu/uci/ics/asterix/installer/events/PatternCreator.java
+++ b/asterix-installer/src/main/java/edu/uci/ics/asterix/installer/events/PatternCreator.java
@@ -315,14 +315,11 @@
         List<Pattern> patternList = new ArrayList<Pattern>();
         Cluster cluster = instance.getCluster();
         Nodeid nodeid = null;
-        String pargs = null;
         Event event = null;
         for (Node node : cluster.getNode()) {
-            String iodevices = node.getIodevices() == null ? cluster.getIodevices() : node.getIodevices();
-            String primaryIODevice = iodevices.split(",")[0].trim();
-            pargs = primaryIODevice + File.separator + InstallerUtil.TXN_LOG_DIR;
+            String txnLogDir = node.getTxnLogDir() == null ? cluster.getTxnLogDir() : node.getTxnLogDir();
             nodeid = new Nodeid(new Value(null, node.getId()));
-            event = new Event("file_delete", nodeid, pargs);
+            event = new Event("file_delete", nodeid, txnLogDir);
             patternList.add(new Pattern(null, 1, null, event));
         }
 
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/AbstractScalarAggregateDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/AbstractScalarAggregateDescriptor.java
index 3de05f8..232eace 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/AbstractScalarAggregateDescriptor.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/AbstractScalarAggregateDescriptor.java
@@ -20,21 +20,23 @@
 
     @Override
     public ICopyEvaluatorFactory createEvaluatorFactory(final ICopyEvaluatorFactory[] args) throws AlgebricksException {
+
+        // The aggregate function will get a SingleFieldFrameTupleReference that points to the result of the ScanCollection.
+        // The list-item will always reside in the first field (column) of the SingleFieldFrameTupleReference.
+        ICopyEvaluatorFactory[] aggFuncArgs = new ICopyEvaluatorFactory[1];
+        aggFuncArgs[0] = new ColumnAccessEvalFactory(0);
+        // Create aggregate function from this scalar version.
+        FunctionIdentifier fid = AsterixBuiltinFunctions.getAggregateFunction(getIdentifier());
+        IFunctionManager mgr = FunctionManagerHolder.getFunctionManager();
+        IFunctionDescriptor fd = mgr.lookupFunction(fid);
+        AbstractAggregateFunctionDynamicDescriptor aggFuncDesc = (AbstractAggregateFunctionDynamicDescriptor) fd;
+        final ICopyAggregateFunctionFactory aggFuncFactory = aggFuncDesc.createAggregateFunctionFactory(aggFuncArgs);
+
         return new ICopyEvaluatorFactory() {
             private static final long serialVersionUID = 1L;
 
             @Override
             public ICopyEvaluator createEvaluator(IDataOutputProvider output) throws AlgebricksException {
-                // The aggregate function will get a SingleFieldFrameTupleReference that points to the result of the ScanCollection.
-                // The list-item will always reside in the first field (column) of the SingleFieldFrameTupleReference.
-                ICopyEvaluatorFactory[] aggFuncArgs = new ICopyEvaluatorFactory[1];
-                aggFuncArgs[0] = new ColumnAccessEvalFactory(0);
-                // Create aggregate function from this scalar version.
-                FunctionIdentifier fid = AsterixBuiltinFunctions.getAggregateFunction(getIdentifier());
-                IFunctionManager mgr = FunctionManagerHolder.getFunctionManager();
-                IFunctionDescriptor fd = mgr.lookupFunction(fid);
-                AbstractAggregateFunctionDynamicDescriptor aggFuncDesc = (AbstractAggregateFunctionDynamicDescriptor) fd;
-                ICopyAggregateFunctionFactory aggFuncFactory = aggFuncDesc.createAggregateFunctionFactory(aggFuncArgs);
                 // Use ScanCollection to iterate over list items.
                 ScanCollectionUnnestingFunctionFactory scanCollectionFactory = new ScanCollectionUnnestingFunctionFactory(
                         args[0]);
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/LockWaiterManager.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/LockWaiterManager.java
index dbe76ff..bd414de 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/LockWaiterManager.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/LockWaiterManager.java
@@ -223,45 +223,35 @@
      */
     private void shrink() {
         int i;
-        boolean bContiguous = true;
-        int decreaseCount = 0;
+        int removeCount = 0;
         int size = pArray.size();
         int maxDecreaseCount = size / 2;
         ChildLockWaiterArrayManager child;
-        for (i = size - 1; i >= 0; i--) {
-            child = pArray.get(i);
-            if (child.isEmpty() || child.isDeinitialized()) {
-                if (bContiguous) {
-                    pArray.remove(i);
-                    if (++decreaseCount == maxDecreaseCount) {
-                        break;
-                    }
-                } else {
-                    bContiguous = false;
-                    if (child.isEmpty()) {
-                        child.deinitialize();
-                        if (++decreaseCount == maxDecreaseCount) {
-                            break;
-                        }
-                    }
-                }
-            } else {
-                bContiguous = false;
+
+        //The first buffer never be deinitialized.
+        for (i = 1; i < size; i++) {
+            if (pArray.get(i).isEmpty()) {
+                pArray.get(i).deinitialize();
             }
         }
 
-        //reset allocChild when the child is removed or deinitialized.
-        size = pArray.size();
-        if (allocChild >= size || pArray.get(allocChild).isDeinitialized()) {
-            //set allocChild to any initialized one.
-            //It is guaranteed that there is at least one initialized child.
-            for (i = 0; i < size; i++) {
-                if (!pArray.get(i).isDeinitialized()) {
-                    allocChild = i;
+        //remove the empty buffers from the end
+        for (i = size - 1; i >= 1; i--) {
+            child = pArray.get(i);
+            if (child.isDeinitialized()) {
+                pArray.remove(i);
+                if (++removeCount == maxDecreaseCount) {
                     break;
                 }
+            } else {
+                break;
             }
         }
+        
+        //reset allocChild to the first buffer
+        allocChild = 0;
+
+        isShrinkTimerOn = false;
     }
 
     public String prettyPrint() {
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/logging/LogManager.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/logging/LogManager.java
index 199fd0f..38d39cc 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/logging/LogManager.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/logging/LogManager.java
@@ -259,9 +259,16 @@
             }
 
             if (forwardPage) {
-
+                logPages[prevPage].acquireReadLatch();
+                // increment the counter as the transaction thread now holds a
+                // space in the log page and hence is an owner.
+                logPages[prevPage].incRefCnt();
+                logPages[prevPage].releaseReadLatch();
+                
                 // forward the nextWriteOffset in the log page
-                logPages[pageIndex].setBufferNextWriteOffset(logPageSize);
+                logPages[prevPage].setBufferNextWriteOffset(logPageSize);
+                
+                logPages[prevPage].decRefCnt();
 
                 addFlushRequest(prevPage, old, false);
 
@@ -433,7 +440,7 @@
 
                 // indicating that the transaction thread has released ownership
                 decremented = true;
-                
+
                 addFlushRequest(pageIndex, currentLSN, false);
             } else if (logType == LogType.COMMIT) {
 
@@ -872,16 +879,16 @@
                         if (logManager.getLastFlushedLsn().get() + 1 > logManager.getCurrentLsn().get()) {
                             logManager.getCurrentLsn().set(logManager.getLastFlushedLsn().get() + 1);
                         }
-                        
+
                         // Map the log page to a new region in the log file if the flushOffset reached the logPageSize
                         if (afterFlushOffset == logPageSize) {
-                            long diskNextWriteOffset = logManager.getLogPages()[flushPageIndex].getDiskNextWriteOffset()
-                                    + logBufferSize;
+                            long diskNextWriteOffset = logManager.getLogPages()[flushPageIndex]
+                                    .getDiskNextWriteOffset() + logBufferSize;
                             logManager.resetLogPage(logManager.getLastFlushedLsn().get() + 1 + logBufferSize,
                                     diskNextWriteOffset, flushPageIndex);
                             resetFlushPageIndex = true;
                         }
-                        
+
                         // decrement activeTxnCountOnIndexes
                         logManager.decrementActiveTxnCountOnIndexes(flushPageIndex);