diff --git a/asterix-algebra/src/main/java/edu/uci/ics/asterix/algebra/operators/physical/CommitRuntime.java b/asterix-algebra/src/main/java/edu/uci/ics/asterix/algebra/operators/physical/CommitRuntime.java
index 269526b..76a2bee 100644
--- a/asterix-algebra/src/main/java/edu/uci/ics/asterix/algebra/operators/physical/CommitRuntime.java
+++ b/asterix-algebra/src/main/java/edu/uci/ics/asterix/algebra/operators/physical/CommitRuntime.java
@@ -21,7 +21,6 @@
 import edu.uci.ics.asterix.common.exceptions.ACIDException;
 import edu.uci.ics.asterix.common.transactions.DatasetId;
 import edu.uci.ics.asterix.common.transactions.ITransactionContext;
-import edu.uci.ics.asterix.common.transactions.ITransactionContext.TransactionType;
 import edu.uci.ics.asterix.common.transactions.ITransactionManager;
 import edu.uci.ics.asterix.common.transactions.JobId;
 import edu.uci.ics.hyracks.algebricks.runtime.base.IPushRuntime;
@@ -35,7 +34,7 @@
 import edu.uci.ics.hyracks.storage.am.bloomfilter.impls.MurmurHash128Bit;
 
 public class CommitRuntime implements IPushRuntime {
-    
+
     private final static long SEED = 0L;
 
     private final IHyracksTaskContext hyracksTaskCtx;
@@ -44,7 +43,7 @@
     private final DatasetId datasetId;
     private final int[] primaryKeyFields;
     private final boolean isWriteTransaction;
-    private final long[] longHashes; 
+    private final long[] longHashes;
 
     private ITransactionContext transactionContext;
     private RecordDescriptor inputRecordDesc;
@@ -54,23 +53,22 @@
     public CommitRuntime(IHyracksTaskContext ctx, JobId jobId, int datasetId, int[] primaryKeyFields,
             boolean isWriteTransaction) {
         this.hyracksTaskCtx = ctx;
-        IAsterixAppRuntimeContext runtimeCtx = (IAsterixAppRuntimeContext) ctx.getJobletContext().getApplicationContext()
-                .getApplicationObject();
+        IAsterixAppRuntimeContext runtimeCtx = (IAsterixAppRuntimeContext) ctx.getJobletContext()
+                .getApplicationContext().getApplicationObject();
         this.transactionManager = runtimeCtx.getTransactionSubsystem().getTransactionManager();
         this.jobId = jobId;
         this.datasetId = new DatasetId(datasetId);
         this.primaryKeyFields = primaryKeyFields;
         this.frameTupleReference = new FrameTupleReference();
         this.isWriteTransaction = isWriteTransaction;
-        this.longHashes= new long[2];
+        this.longHashes = new long[2];
     }
 
     @Override
     public void open() throws HyracksDataException {
         try {
             transactionContext = transactionManager.getTransactionContext(jobId);
-            transactionContext.setTransactionType(isWriteTransaction ? TransactionType.READ_WRITE
-                    : TransactionType.READ);
+            transactionContext.isWriteTxn(isWriteTransaction);
         } catch (ACIDException e) {
             throw new HyracksDataException(e);
         }
@@ -91,10 +89,10 @@
             }
         }
     }
-    
+
     private int computePrimaryKeyHashValue(ITupleReference tuple, int[] primaryKeyFields) {
         MurmurHash128Bit.hash3_x64_128(tuple, primaryKeyFields, SEED, longHashes);
-        return Math.abs((int) longHashes[0]); 
+        return Math.abs((int) longHashes[0]);
     }
 
     @Override
diff --git a/asterix-app/src/main/java/edu/uci/ics/asterix/api/common/AsterixAppRuntimeContext.java b/asterix-app/src/main/java/edu/uci/ics/asterix/api/common/AsterixAppRuntimeContext.java
index 18a81e5..bba6272 100644
--- a/asterix-app/src/main/java/edu/uci/ics/asterix/api/common/AsterixAppRuntimeContext.java
+++ b/asterix-app/src/main/java/edu/uci/ics/asterix/api/common/AsterixAppRuntimeContext.java
@@ -121,7 +121,7 @@
         IAsterixAppRuntimeContextProvider asterixAppRuntimeContextProvider = new AsterixAppRuntimeContextProviderForRecovery(
                 this);
         txnSubsystem = new TransactionSubsystem(ncApplicationContext.getNodeId(), asterixAppRuntimeContextProvider,
-                txnProperties);
+                txnProperties, ioManager.getIODevices().size());
         isShuttingdown = false;
 
         // The order of registration is important. The buffer cache must registered before recovery and transaction managers.
diff --git a/asterix-common/src/main/java/edu/uci/ics/asterix/common/transactions/ILogPage.java b/asterix-common/src/main/java/edu/uci/ics/asterix/common/transactions/ILogPage.java
index 7d9bba7..be205a9 100644
--- a/asterix-common/src/main/java/edu/uci/ics/asterix/common/transactions/ILogPage.java
+++ b/asterix-common/src/main/java/edu/uci/ics/asterix/common/transactions/ILogPage.java
@@ -18,6 +18,6 @@
 
     public void append(ILogRecord logRecord, long appendLsn);
 
-    public void flush() throws InterruptedException;
+    public void flush();
 
 }
\ No newline at end of file
diff --git a/asterix-common/src/main/java/edu/uci/ics/asterix/common/transactions/ITransactionContext.java b/asterix-common/src/main/java/edu/uci/ics/asterix/common/transactions/ITransactionContext.java
index b9ad1bd..8984403 100644
--- a/asterix-common/src/main/java/edu/uci/ics/asterix/common/transactions/ITransactionContext.java
+++ b/asterix-common/src/main/java/edu/uci/ics/asterix/common/transactions/ITransactionContext.java
@@ -14,7 +14,6 @@
  */
 package edu.uci.ics.asterix.common.transactions;
 
-import edu.uci.ics.asterix.common.transactions.ITransactionManager.TransactionState;
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndex;
 
 public interface ITransactionContext {
@@ -24,17 +23,13 @@
 
     public JobId getJobId();
 
-    public void setStartWaitTime(long time);
+    public void isTimeout(boolean isTimeout);
 
-    public long getStartWaitTime();
+    public boolean isTimeout();
 
-    public void setStatus(int status);
+    public void setTxnState(int txnState);
 
-    public int getStatus();
-
-    public void setTxnState(TransactionState txnState);
-
-    public TransactionState getTxnState();
+    public int getTxnState();
 
     public long getFirstLSN();
 
@@ -42,25 +37,20 @@
 
     public void setLastLSN(long resourceId, long LSN);
 
-    public TransactionType getTransactionType();
+    public boolean isWriteTxn();
 
-    public void setTransactionType(TransactionType transactionType);
+    public void isWriteTxn(boolean isWriterTxn);
 
     public String prettyPrint();
 
-    // used for showing a transaction is not waiting.
-    public static final long INVALID_TIME = -1l;
+    public void isMetadataTransaction(boolean isMetadataTxn);
 
-    public static final int ACTIVE_STATUS = 0;
-    public static final int TIMED_OUT_STATUS = 1;
+    public boolean isMetadataTransaction();
 
-    public enum TransactionType {
-        READ,
-        READ_WRITE
-    }
+    public void notifyOptracker(boolean isJobLevelCommit);
 
-    public void setExclusiveJobLevelCommit();
+    public void decrementNumOfActiveJobs();
 
-    void notifyOptracker(boolean isJobLevelCommit);
+    public int getNumOfActiveJobs();
 
 }
diff --git a/asterix-common/src/main/java/edu/uci/ics/asterix/common/transactions/ITransactionManager.java b/asterix-common/src/main/java/edu/uci/ics/asterix/common/transactions/ITransactionManager.java
index 9a99dc9..5404ceb 100644
--- a/asterix-common/src/main/java/edu/uci/ics/asterix/common/transactions/ITransactionManager.java
+++ b/asterix-common/src/main/java/edu/uci/ics/asterix/common/transactions/ITransactionManager.java
@@ -29,12 +29,17 @@
      * transaction has committed. ABORTED: The transaction has aborted.
      * TIMED_OUT: The transaction has timed out waiting to acquire a lock.
      */
-    public enum TransactionState {
-        ACTIVE,
-        COMMITTED,
-        ABORTED,
-        TIMED_OUT,
-    };
+//    public enum TransactionState {
+//        ACTIVE,
+//        COMMITTED,
+//        ABORTED,
+//        TIMED_OUT,
+//    };
+    
+    public static final int ACTIVE = 0;
+    public static final int COMMITTED = 1;
+    public static final int ABORTED = 2;
+    public static final int TIMED_OUT = 3;
 
     /**
      * Begins a transaction identified by a transaction id and returns the
diff --git a/asterix-metadata/src/main/java/edu/uci/ics/asterix/metadata/MetadataNode.java b/asterix-metadata/src/main/java/edu/uci/ics/asterix/metadata/MetadataNode.java
index 13f1ec0..f48f267 100644
--- a/asterix-metadata/src/main/java/edu/uci/ics/asterix/metadata/MetadataNode.java
+++ b/asterix-metadata/src/main/java/edu/uci/ics/asterix/metadata/MetadataNode.java
@@ -29,7 +29,6 @@
 import edu.uci.ics.asterix.common.transactions.DatasetId;
 import edu.uci.ics.asterix.common.transactions.IRecoveryManager.ResourceType;
 import edu.uci.ics.asterix.common.transactions.ITransactionContext;
-import edu.uci.ics.asterix.common.transactions.ITransactionContext.TransactionType;
 import edu.uci.ics.asterix.common.transactions.ITransactionSubsystem;
 import edu.uci.ics.asterix.common.transactions.JobId;
 import edu.uci.ics.asterix.formats.nontagged.AqlSerializerDeserializerProvider;
@@ -111,13 +110,12 @@
     @Override
     public void beginTransaction(JobId transactionId) throws ACIDException, RemoteException {
         ITransactionContext txnCtx = transactionSubsystem.getTransactionManager().beginTransaction(transactionId);
-        txnCtx.setExclusiveJobLevelCommit();
+        txnCtx.isMetadataTransaction(true);
     }
 
     @Override
     public void commitTransaction(JobId jobId) throws RemoteException, ACIDException {
         ITransactionContext txnCtx = transactionSubsystem.getTransactionManager().getTransactionContext(jobId);
-        txnCtx.setExclusiveJobLevelCommit();
         transactionSubsystem.getTransactionManager().commitTransaction(txnCtx, new DatasetId(-1), -1);
     }
 
@@ -276,7 +274,7 @@
         ILSMIndexAccessor indexAccessor = lsmIndex.createAccessor(modCallback, NoOpOperationCallback.INSTANCE);
 
         ITransactionContext txnCtx = transactionSubsystem.getTransactionManager().getTransactionContext(jobId);
-        txnCtx.setTransactionType(TransactionType.READ_WRITE);
+        txnCtx.isWriteTxn(true);
         txnCtx.registerIndexAndCallback(resourceID, lsmIndex, (AbstractOperationCallback) modCallback,
                 metadataIndex.isPrimaryIndex());
 
@@ -584,7 +582,7 @@
         ILSMIndexAccessor indexAccessor = lsmIndex.createAccessor(modCallback, NoOpOperationCallback.INSTANCE);
 
         ITransactionContext txnCtx = transactionSubsystem.getTransactionManager().getTransactionContext(jobId);
-        txnCtx.setTransactionType(TransactionType.READ_WRITE);
+        txnCtx.isWriteTxn(true);
         txnCtx.registerIndexAndCallback(resourceID, lsmIndex, (AbstractOperationCallback) modCallback,
                 metadataIndex.isPrimaryIndex());
 
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/job/listener/JobEventListenerFactory.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/job/listener/JobEventListenerFactory.java
index 8092ecd..2782e63 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/job/listener/JobEventListenerFactory.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/job/listener/JobEventListenerFactory.java
@@ -18,7 +18,6 @@
 import edu.uci.ics.asterix.common.exceptions.ACIDException;
 import edu.uci.ics.asterix.common.transactions.DatasetId;
 import edu.uci.ics.asterix.common.transactions.ITransactionContext;
-import edu.uci.ics.asterix.common.transactions.ITransactionContext.TransactionType;
 import edu.uci.ics.asterix.common.transactions.ITransactionManager;
 import edu.uci.ics.asterix.common.transactions.JobId;
 import edu.uci.ics.hyracks.api.context.IHyracksJobletContext;
@@ -51,8 +50,7 @@
                     ITransactionManager txnManager = ((IAsterixAppRuntimeContext) jobletContext.getApplicationContext()
                             .getApplicationObject()).getTransactionSubsystem().getTransactionManager();
                     ITransactionContext txnContext = txnManager.getTransactionContext(jobId);
-                    txnContext.setTransactionType(transactionalWrite ? TransactionType.READ_WRITE
-                            : TransactionType.READ);
+                    txnContext.isWriteTxn(transactionalWrite);
                     txnManager.completedTransaction(txnContext, new DatasetId(-1), -1,
                             !(jobStatus == JobStatus.FAILURE));
                 } catch (ACIDException e) {
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/LockManager.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/LockManager.java
index fdfc822..759b45b 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/LockManager.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/LockManager.java
@@ -31,7 +31,7 @@
 import edu.uci.ics.asterix.common.transactions.ILockManager;
 import edu.uci.ics.asterix.common.transactions.ILogRecord;
 import edu.uci.ics.asterix.common.transactions.ITransactionContext;
-import edu.uci.ics.asterix.common.transactions.ITransactionManager.TransactionState;
+import edu.uci.ics.asterix.common.transactions.ITransactionManager;
 import edu.uci.ics.asterix.common.transactions.JobId;
 import edu.uci.ics.asterix.transaction.management.service.logging.LogPage;
 import edu.uci.ics.asterix.transaction.management.service.logging.LogPageReader;
@@ -305,9 +305,9 @@
     }
 
     private void validateJob(ITransactionContext txnContext) throws ACIDException {
-        if (txnContext.getTxnState() == TransactionState.ABORTED) {
+        if (txnContext.getTxnState() == ITransactionManager.ABORTED) {
             throw new ACIDException("" + txnContext.getJobId() + " is in ABORTED state.");
-        } else if (txnContext.getStatus() == ITransactionContext.TIMED_OUT_STATUS) {
+        } else if (txnContext.isTimeout()) {
             requestAbort(txnContext);
         }
     }
@@ -708,7 +708,7 @@
             //The lock will be released when the entity-commit log is flushed. 
             if (commitFlag && entityInfoManager.getEntityLockCount(entityInfo) == 1
                     && entityInfoManager.getDatasetLockCount(entityInfo) == 1) {
-                if (txnContext.getTransactionType().equals(ITransactionContext.TransactionType.READ_WRITE)) {
+                if (txnContext.isWriteTxn()) {
                     logRecord.formCommitLogRecord(txnContext, LogType.ENTITY_COMMIT, jobId.getId(), datasetId.getId(),
                             entityHashValue);
                     txnSubsystem.getLogManager().log(logRecord);
@@ -972,8 +972,8 @@
             jobHT.remove(jobId);
 
             if (existWaiter) {
-                txnContext.setStatus(ITransactionContext.TIMED_OUT_STATUS);
-                txnContext.setTxnState(TransactionState.ABORTED);
+                txnContext.isTimeout(true);
+                txnContext.setTxnState(ITransactionManager.ABORTED);
             }
 
             if (IS_DEBUG_MODE) {
@@ -1823,7 +1823,7 @@
             //waiter woke up -> remove/deallocate waiter object and abort if timeout
             latchLockTable();
 
-            if (txnContext.getStatus() == ITransactionContext.TIMED_OUT_STATUS || waiter.isVictim()) {
+            if (txnContext.isTimeout() || waiter.isVictim()) {
                 requestAbort(txnContext);
             }
 
@@ -1880,8 +1880,7 @@
     }
 
     private void requestAbort(ITransactionContext txnContext) throws ACIDException {
-        txnContext.setStatus(ITransactionContext.TIMED_OUT_STATUS);
-        txnContext.setStartWaitTime(ITransactionContext.INVALID_TIME);
+        txnContext.isTimeout(true);
         throw new ACIDException("Transaction " + txnContext.getJobId()
                 + " should abort (requested by the Lock Manager)");
     }
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/LockManagerDeterministicUnitTest.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/LockManagerDeterministicUnitTest.java
index e97c177..43164cf 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/LockManagerDeterministicUnitTest.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/LockManagerDeterministicUnitTest.java
@@ -21,17 +21,13 @@
 import java.util.NoSuchElementException;
 import java.util.Scanner;
 
-import edu.uci.ics.asterix.common.config.AsterixCompilerProperties;
-import edu.uci.ics.asterix.common.config.AsterixExternalProperties;
-import edu.uci.ics.asterix.common.config.AsterixMetadataProperties;
 import edu.uci.ics.asterix.common.config.AsterixPropertiesAccessor;
-import edu.uci.ics.asterix.common.config.AsterixStorageProperties;
 import edu.uci.ics.asterix.common.config.AsterixTransactionProperties;
 import edu.uci.ics.asterix.common.exceptions.ACIDException;
 import edu.uci.ics.asterix.common.exceptions.AsterixException;
 import edu.uci.ics.asterix.common.transactions.DatasetId;
 import edu.uci.ics.asterix.common.transactions.ILockManager;
-import edu.uci.ics.asterix.common.transactions.ITransactionManager.TransactionState;
+import edu.uci.ics.asterix.common.transactions.ITransactionManager;
 import edu.uci.ics.asterix.common.transactions.JobId;
 import edu.uci.ics.asterix.transaction.management.service.transaction.TransactionContext;
 import edu.uci.ics.asterix.transaction.management.service.transaction.TransactionManagementConstants.LockManagerConstants.LockMode;
@@ -62,7 +58,7 @@
 
     public LockRequestController(String requestFileName) throws ACIDException, AsterixException {
         this.txnProvider = new TransactionSubsystem("LockManagerPredefinedUnitTest", null,
-                new AsterixTransactionProperties(new AsterixPropertiesAccessor()));
+                new AsterixTransactionProperties(new AsterixPropertiesAccessor()), 1);
         this.workerReadyQueue = new WorkerReadyQueue();
         this.requestList = new ArrayList<LockRequest>();
         this.expectedResultList = new ArrayList<ArrayList<Integer>>();
@@ -281,7 +277,7 @@
                     lockMode = scanner.next();
                     txnContext = jobMap.get(jobId);
                     if (txnContext == null) {
-                        txnContext = new TransactionContext(new JobId(jobId), txnProvider);
+                        txnContext = new TransactionContext(new JobId(jobId), txnProvider, 1);
                         jobMap.put(jobId, txnContext);
                     }
                     log("LockRequest[" + i++ + "]:T" + threadId + "," + requestType + ",J" + jobId + ",D" + datasetId
@@ -428,9 +424,9 @@
             try {
                 sendRequest(lockRequest);
             } catch (ACIDException e) {
-                if (lockRequest.txnContext.getStatus() == TransactionContext.TIMED_OUT_STATUS) {
-                    if (lockRequest.txnContext.getTxnState() != TransactionState.ABORTED) {
-                        lockRequest.txnContext.setTxnState(TransactionState.ABORTED);
+                if (lockRequest.txnContext.isTimeout()) {
+                    if (lockRequest.txnContext.getTxnState() != ITransactionManager.ABORTED) {
+                        lockRequest.txnContext.setTxnState(ITransactionManager.ABORTED);
                         log("*** " + lockRequest.txnContext.getJobId() + " lock request causing deadlock ***");
                         log("Abort --> Releasing all locks acquired by " + lockRequest.txnContext.getJobId());
                         try {
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/LockManagerRandomUnitTest.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/LockManagerRandomUnitTest.java
index f73460d..aba41a9 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/LockManagerRandomUnitTest.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/LockManagerRandomUnitTest.java
@@ -24,7 +24,7 @@
 import edu.uci.ics.asterix.common.transactions.DatasetId;
 import edu.uci.ics.asterix.common.transactions.ILockManager;
 import edu.uci.ics.asterix.common.transactions.ITransactionContext;
-import edu.uci.ics.asterix.common.transactions.ITransactionManager.TransactionState;
+import edu.uci.ics.asterix.common.transactions.ITransactionManager;
 import edu.uci.ics.asterix.common.transactions.JobId;
 import edu.uci.ics.asterix.transaction.management.service.transaction.TransactionContext;
 import edu.uci.ics.asterix.transaction.management.service.transaction.TransactionManagementConstants.LockManagerConstants.LockMode;
@@ -48,7 +48,7 @@
     public static void main(String args[]) throws ACIDException, AsterixException {
         int i;
         TransactionSubsystem txnProvider = new TransactionSubsystem("LockManagerRandomUnitTest", null,
-                new AsterixTransactionProperties(new AsterixPropertiesAccessor()));
+                new AsterixTransactionProperties(new AsterixPropertiesAccessor()), 1);
         rand = new Random(System.currentTimeMillis());
         for (i = 0; i < MAX_NUM_OF_ENTITY_LOCK_JOB; i++) {
             System.out.println("Creating " + i + "th EntityLockJob..");
@@ -119,7 +119,7 @@
 
     private static TransactionContext generateTxnContext(TransactionSubsystem txnProvider) {
         try {
-            return new TransactionContext(new JobId(jobId++), txnProvider);
+            return new TransactionContext(new JobId(jobId++), txnProvider, 1);
         } catch (ACIDException e) {
             e.printStackTrace();
             return null;
@@ -287,8 +287,8 @@
         } else {
             try {
                 synchronized (txnContext) {
-                    if (txnContext.getTxnState() != TransactionState.ABORTED) {
-                        txnContext.setTxnState(TransactionState.ABORTED);
+                    if (txnContext.getTxnState() != ITransactionManager.ABORTED) {
+                        txnContext.setTxnState(ITransactionManager.ABORTED);
                         mayRelease = true;
                     }
                 }
@@ -446,9 +446,9 @@
                 try {
                     lockMgr.lock(request.datasetIdObj, request.entityHashValue, request.lockMode, request.txnContext);
                 } catch (ACIDException e) {
-                    if (request.txnContext.getStatus() == TransactionContext.TIMED_OUT_STATUS) {
-                        if (request.txnContext.getTxnState() != TransactionState.ABORTED) {
-                            request.txnContext.setTxnState(TransactionState.ABORTED);
+                    if (request.txnContext.isTimeout()) {
+                        if (request.txnContext.getTxnState() != ITransactionManager.ABORTED) {
+                            request.txnContext.setTxnState(ITransactionManager.ABORTED);
                             log("*** " + request.txnContext.getJobId() + " lock request causing deadlock ***");
                             log("Abort --> Releasing all locks acquired by " + request.txnContext.getJobId());
                             try {
@@ -469,9 +469,9 @@
                     lockMgr.instantLock(request.datasetIdObj, request.entityHashValue, request.lockMode,
                             request.txnContext);
                 } catch (ACIDException e) {
-                    if (request.txnContext.getStatus() == TransactionContext.TIMED_OUT_STATUS) {
-                        if (request.txnContext.getTxnState() != TransactionState.ABORTED) {
-                            request.txnContext.setTxnState(TransactionState.ABORTED);
+                    if (request.txnContext.isTimeout()) {
+                        if (request.txnContext.getTxnState() != ITransactionManager.ABORTED) {
+                            request.txnContext.setTxnState(ITransactionManager.ABORTED);
                             log("*** " + request.txnContext.getJobId() + " lock request causing deadlock ***");
                             log("Abort --> Releasing all locks acquired by " + request.txnContext.getJobId());
                             try {
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 49c07c1..e378789 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
@@ -387,7 +387,10 @@
 
     public void terminate() {
         if (flushPage != null) {
-            flushPage.isStop(true);
+            synchronized (flushPage) {
+                flushPage.isStop(true);
+                flushPage.notify();
+            }
         }
         stop = true;
         this.interrupt();
@@ -400,6 +403,9 @@
             try {
                 flushPage = flushQ.take();
                 flushPage.flush();
+                if (stop) {
+                    break;
+                }
             } catch (InterruptedException e) {
                 if (stop) {
                     break;
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/logging/LogPage.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/logging/LogPage.java
index 5c051a3..04200a7 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/logging/LogPage.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/logging/LogPage.java
@@ -120,7 +120,7 @@
     ////////////////////////////////////
 
     @Override
-    public void flush() throws InterruptedException {
+    public void flush() {
         try {
             int endOffset;
             while (!full.get()) {
@@ -128,12 +128,12 @@
                     if (appendOffset - flushOffset == 0 && !full.get()) {
                         try {
                             this.wait();
-                        } catch (InterruptedException e) {
                             if (stop) {
-                                throw e;
-                            } else {
-                                throw new IllegalStateException(e);
+                                fileChannel.close();
+                                break;
                             }
+                        } catch (InterruptedException e) {
+                            throw new IllegalStateException(e);
                         }
                     }
                     endOffset = appendOffset;
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/transaction/TransactionContext.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/transaction/TransactionContext.java
index eee6bad..504c5e2 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/transaction/TransactionContext.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/transaction/TransactionContext.java
@@ -17,6 +17,8 @@
 import java.io.Serializable;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
 
 import edu.uci.ics.asterix.common.context.BaseOperationTracker;
@@ -24,7 +26,7 @@
 import edu.uci.ics.asterix.common.exceptions.ACIDException;
 import edu.uci.ics.asterix.common.transactions.AbstractOperationCallback;
 import edu.uci.ics.asterix.common.transactions.ITransactionContext;
-import edu.uci.ics.asterix.common.transactions.ITransactionManager.TransactionState;
+import edu.uci.ics.asterix.common.transactions.ITransactionManager;
 import edu.uci.ics.asterix.common.transactions.JobId;
 import edu.uci.ics.asterix.common.transactions.MutableLong;
 import edu.uci.ics.asterix.transaction.management.opcallbacks.PrimaryIndexModificationOperationCallback;
@@ -33,41 +35,73 @@
 import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndex;
 import edu.uci.ics.hyracks.storage.am.lsm.common.impls.LSMOperationType;
 
-/**
- * Represents a holder object that contains all information related to a
- * transaction. A TransactionContext instance can be used as a token and
- * provided to Transaction sub-systems (Log/Lock/Recovery/Transaction)Manager to
- * initiate an operation on the behalf of the transaction associated with the
- * context.
+/*
+ * An object of TransactionContext is created and accessed(read/written) by multiple threads which work for
+ * a single job identified by a jobId. Thus, the member variables in the object can be read/written
+ * concurrently. Please see each variable declaration to know which one is accessed concurrently and
+ * which one is not. 
  */
 public class TransactionContext implements ITransactionContext, Serializable {
 
     private static final long serialVersionUID = -6105616785783310111L;
     private TransactionSubsystem transactionSubsystem;
-    private final AtomicLong firstLSN;
-    private final AtomicLong lastLSN;
-    private TransactionState txnState;
-    private long startWaitTime;
-    private int status;
-    private TransactionType transactionType = TransactionType.READ;
-    private JobId jobId;
-    private boolean exlusiveJobLevelCommit;
-    private final Map<MutableLong, BaseOperationTracker> indexMap;
+    
+    //jobId is set once and read concurrently.
+    private final JobId jobId;
+
+    //There are no concurrent writers on both firstLSN and lastLSN 
+    //since both values are updated by serialized log appenders. 
+    //But readers and writers can be different threads, 
+    //so both LSNs are atomic variables in order to be read and written atomically.
+    private AtomicLong firstLSN;
+    private AtomicLong lastLSN;
+
+    //txnState is read and written concurrently.
+    private AtomicInteger txnState;
+
+    //isTimeout are read and written under the lockMgr's tableLatch
+    //Thus, no other synchronization is required separately.
+    private boolean isTimeout;
+
+    //isWriteTxn can be set concurrently by multiple threads. 
+    private AtomicBoolean isWriteTxn;
+
+    //isMetadataTxn is accessed by a single thread since the metadata is not partitioned
+    private boolean isMetadataTxn;
+
+    //indexMap is concurrently accessed by multiple threads, 
+    //so those threads are synchronized on indexMap object itself
+    private Map<MutableLong, BaseOperationTracker> indexMap;
+
+    //TODO: fix ComponentLSNs' issues. 
+    //primaryIndex, primaryIndexCallback, and primaryIndexOptracker will be modified accordingly
+    //when the issues of componentLSNs are fixed.  
     private ILSMIndex primaryIndex;
     private PrimaryIndexModificationOperationCallback primaryIndexCallback;
     private PrimaryIndexOperationTracker primaryIndexOpTracker;
-    private final MutableLong tempResourceIdForRegister;
-    private final MutableLong tempResourceIdForSetLSN;
-    private final LogRecord logRecord;
 
-    public TransactionContext(JobId jobId, TransactionSubsystem transactionSubsystem) throws ACIDException {
+    //The following three variables are used as temporary variables in order to avoid object creations.
+    //Those are used in synchronized methods. 
+    private MutableLong tempResourceIdForRegister;
+    private MutableLong tempResourceIdForSetLSN;
+    private LogRecord logRecord;
+
+    //numOfActiveJobs is accessed under a synchronized block on TransactionContext in callers.
+    private int numOfActiveJobs;
+
+    //TODO: implement transactionContext pool in order to avoid object creations.
+    //      also, the pool can throttle the number of concurrent active jobs at every moment. 
+    public TransactionContext(JobId jobId, TransactionSubsystem transactionSubsystem, int numOfPartitions)
+            throws ACIDException {
         this.jobId = jobId;
         this.transactionSubsystem = transactionSubsystem;
+        this.numOfActiveJobs = numOfPartitions;
         firstLSN = new AtomicLong(-1);
         lastLSN = new AtomicLong(-1);
-        txnState = TransactionState.ACTIVE;
-        startWaitTime = INVALID_TIME;
-        status = ACTIVE_STATUS;
+        txnState = new AtomicInteger(ITransactionManager.ACTIVE);
+        isTimeout = false;
+        isWriteTxn = new AtomicBoolean(false);
+        isMetadataTxn = false;
         indexMap = new HashMap<MutableLong, BaseOperationTracker>();
         primaryIndex = null;
         tempResourceIdForRegister = new MutableLong();
@@ -109,9 +143,9 @@
     @Override
     public void notifyOptracker(boolean isJobLevelCommit) {
         try {
-            if (isJobLevelCommit && exlusiveJobLevelCommit) {
+            if (isJobLevelCommit && isMetadataTxn) {
                 primaryIndexOpTracker.exclusiveJobCommitted();
-            } else if (!isJobLevelCommit){         
+            } else if (!isJobLevelCommit) {
                 primaryIndexOpTracker
                         .completeOperation(null, LSMOperationType.MODIFICATION, null, primaryIndexCallback);
             }
@@ -120,12 +154,12 @@
         }
     }
 
-    public void setTransactionType(TransactionType transactionType) {
-        this.transactionType = transactionType;
+    public void isWriteTxn(boolean isWriteTxn) {
+        this.isWriteTxn.set(isWriteTxn);
     }
 
-    public TransactionType getTransactionType() {
-        return transactionType;
+    public boolean isWriteTxn() {
+        return isWriteTxn.get();
     }
 
     @Override
@@ -138,39 +172,24 @@
         return lastLSN.get();
     }
 
-    public void setLastLSN(long LSN) {
-        if (firstLSN.get() == -1) {
-            firstLSN.set(LSN);
-        }
-        lastLSN.set(LSN);
-    }
-
     public JobId getJobId() {
         return jobId;
     }
 
-    public void setStartWaitTime(long time) {
-        this.startWaitTime = time;
+    public void isTimeout(boolean isTimeout) {
+        this.isTimeout = isTimeout;
     }
 
-    public long getStartWaitTime() {
-        return startWaitTime;
+    public boolean isTimeout() {
+        return isTimeout;
     }
 
-    public void setStatus(int status) {
-        this.status = status;
+    public void setTxnState(int txnState) {
+        this.txnState.set(txnState);
     }
 
-    public int getStatus() {
-        return status;
-    }
-
-    public void setTxnState(TransactionState txnState) {
-        this.txnState = txnState;
-    }
-
-    public TransactionState getTxnState() {
-        return txnState;
+    public int getTxnState() {
+        return txnState.get();
     }
 
     @Override
@@ -184,23 +203,38 @@
     }
 
     @Override
-    public void setExclusiveJobLevelCommit() {
-        exlusiveJobLevelCommit = true;
+    public void isMetadataTransaction(boolean isMetadataTxn) {
+        this.isMetadataTxn = isMetadataTxn;
+    }
+
+    @Override
+    public boolean isMetadataTransaction() {
+        return isMetadataTxn;
     }
 
     public String prettyPrint() {
         StringBuilder sb = new StringBuilder();
         sb.append("\n" + jobId + "\n");
-        sb.append("transactionType: " + transactionType);
+        sb.append("isWriterTxn: " + isWriteTxn + "\n");
         sb.append("firstLSN: " + firstLSN.get() + "\n");
         sb.append("lastLSN: " + lastLSN.get() + "\n");
         sb.append("TransactionState: " + txnState + "\n");
-        sb.append("startWaitTime: " + startWaitTime + "\n");
-        sb.append("status: " + status + "\n");
+        sb.append("status: " + isTimeout + "\n");
         return sb.toString();
     }
 
     public LogRecord getLogRecord() {
         return logRecord;
     }
+
+    @Override
+    public void decrementNumOfActiveJobs() {
+        assert numOfActiveJobs > 0;
+        numOfActiveJobs--;
+    }
+
+    @Override
+    public int getNumOfActiveJobs() {
+        return numOfActiveJobs;
+    }
 }
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/transaction/TransactionManager.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/transaction/TransactionManager.java
index 9e18ccf..b73b2db 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/transaction/TransactionManager.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/transaction/TransactionManager.java
@@ -41,22 +41,29 @@
     public static final boolean IS_DEBUG_MODE = false;//true
     private static final Logger LOGGER = Logger.getLogger(TransactionManager.class.getName());
     private final TransactionSubsystem txnSubsystem;
+    private final int numOfPartitions;
     private Map<JobId, ITransactionContext> transactionContextRepository = new ConcurrentHashMap<JobId, ITransactionContext>();
     private AtomicInteger maxJobId = new AtomicInteger(0);
 
-    public TransactionManager(TransactionSubsystem provider) {
+    public TransactionManager(TransactionSubsystem provider, int numOfPartitions) {
         this.txnSubsystem = provider;
+        this.numOfPartitions = numOfPartitions;
     }
 
     @Override
-    public void abortTransaction(ITransactionContext txnContext, DatasetId datasetId, int PKHashVal)
-            throws ACIDException {
-        synchronized (txnContext) {
-            if (txnContext.getTxnState().equals(TransactionState.ABORTED)) {
-                return;
+    public void abortTransaction(ITransactionContext txnCtx, DatasetId datasetId, int PKHashVal) throws ACIDException {
+        synchronized (txnCtx) {
+            if (txnCtx.getTxnState() != ITransactionManager.ABORTED) {
+                txnCtx.setTxnState(ITransactionManager.ABORTED);
+            }
+            if (!txnCtx.isMetadataTransaction()) {
+                txnCtx.decrementNumOfActiveJobs();
+                if (txnCtx.getNumOfActiveJobs() != 0) {
+                    return;
+                }
             }
             try {
-                txnSubsystem.getRecoveryManager().rollbackTransaction(txnContext);
+                txnSubsystem.getRecoveryManager().rollbackTransaction(txnCtx);
             } catch (Exception ae) {
                 String msg = "Could not complete rollback! System is in an inconsistent state";
                 if (LOGGER.isLoggable(Level.SEVERE)) {
@@ -65,9 +72,8 @@
                 ae.printStackTrace();
                 throw new Error(msg);
             } finally {
-                txnSubsystem.getLockManager().releaseLocks(txnContext);
-                transactionContextRepository.remove(txnContext.getJobId());
-                txnContext.setTxnState(TransactionState.ABORTED);
+                txnSubsystem.getLockManager().releaseLocks(txnCtx);
+                transactionContextRepository.remove(txnCtx.getJobId());
             }
         }
     }
@@ -82,7 +88,7 @@
         setMaxJobId(jobId.getId());
         ITransactionContext txnCtx = transactionContextRepository.get(jobId);
         if (txnCtx == null) {
-            txnCtx = new TransactionContext(jobId, txnSubsystem);
+            txnCtx = new TransactionContext(jobId, txnSubsystem, numOfPartitions);
             transactionContextRepository.put(jobId, txnCtx);
         }
         return txnCtx;
@@ -91,10 +97,6 @@
     @Override
     public void commitTransaction(ITransactionContext txnCtx, DatasetId datasetId, int PKHashVal) throws ACIDException {
         synchronized (txnCtx) {
-            if ((txnCtx.getTxnState().equals(TransactionState.COMMITTED))) {
-                return;
-            }
-
             //There is either job-level commit or entity-level commit.
             //The job-level commit will have -1 value both for datasetId and PKHashVal.
 
@@ -105,8 +107,14 @@
             }
 
             //for job-level commit
+            if (!txnCtx.isMetadataTransaction()) {
+                txnCtx.decrementNumOfActiveJobs();
+                if (txnCtx.getNumOfActiveJobs() != 0) {
+                    return;
+                }
+            }
             try {
-                if (txnCtx.getTransactionType().equals(ITransactionContext.TransactionType.READ_WRITE)) {
+                if (txnCtx.isWriteTxn()) {
                     LogRecord logRecord = ((TransactionContext) txnCtx).getLogRecord();
                     logRecord.formCommitLogRecord(txnCtx, LogType.JOB_COMMIT, txnCtx.getJobId().getId(), -1, -1);
                     txnSubsystem.getLogManager().log(logRecord);
@@ -119,7 +127,7 @@
             } finally {
                 txnSubsystem.getLockManager().releaseLocks(txnCtx); // release
                 transactionContextRepository.remove(txnCtx.getJobId());
-                txnCtx.setTxnState(TransactionState.COMMITTED);
+                txnCtx.setTxnState(ITransactionManager.COMMITTED);
             }
         }
     }
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/transaction/TransactionSubsystem.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/transaction/TransactionSubsystem.java
index 2dd7e64..dc06463 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/transaction/TransactionSubsystem.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/transaction/TransactionSubsystem.java
@@ -42,12 +42,12 @@
     private final AsterixTransactionProperties txnProperties;
 
     public TransactionSubsystem(String id, IAsterixAppRuntimeContextProvider asterixAppRuntimeContextProvider,
-            AsterixTransactionProperties txnProperties) throws ACIDException {
+            AsterixTransactionProperties txnProperties, int numOfPartitions) throws ACIDException {
         this.id = id;
         this.txnProperties = txnProperties;
-        this.transactionManager = new TransactionManager(this);
-        this.logManager = new LogManager(this);
+        this.transactionManager = new TransactionManager(this, numOfPartitions);
         this.lockManager = new LockManager(this);
+        this.logManager = new LogManager(this);
         this.recoveryManager = new RecoveryManager(this);
         this.asterixAppRuntimeContextProvider = asterixAppRuntimeContextProvider;
         if (asterixAppRuntimeContextProvider != null) {