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 bba6272..18a81e5 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, ioManager.getIODevices().size());
+                txnProperties);
         isShuttingdown = false;
 
         // The order of registration is important. The buffer cache must registered before recovery and transaction managers.
diff --git a/asterix-app/src/main/java/edu/uci/ics/asterix/aql/translator/AqlTranslator.java b/asterix-app/src/main/java/edu/uci/ics/asterix/aql/translator/AqlTranslator.java
index 418e0a6..3fa9e56 100644
--- a/asterix-app/src/main/java/edu/uci/ics/asterix/aql/translator/AqlTranslator.java
+++ b/asterix-app/src/main/java/edu/uci/ics/asterix/aql/translator/AqlTranslator.java
@@ -128,6 +128,7 @@
         ADDED_PENDINGOP_RECORD_TO_METADATA
     }
 
+    public static final boolean IS_DEBUG_MODE = true;//true
     private final List<Statement> aqlStatements;
     private final PrintWriter out;
     private final SessionConfig sessionConfig;
@@ -1506,8 +1507,9 @@
 
     private void abort(Exception rootE, Exception parentE, MetadataTransactionContext mdTxnCtx) {
         try {
-            //TODO: remove stacktrace
-            rootE.printStackTrace();
+            if (IS_DEBUG_MODE) {
+                rootE.printStackTrace();
+            }
             MetadataManager.INSTANCE.abortTransaction(mdTxnCtx);
         } catch (Exception e2) {
             parentE.addSuppressed(e2);
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 8984403..531b10f 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
@@ -48,9 +48,4 @@
     public boolean isMetadataTransaction();
 
     public void notifyOptracker(boolean isJobLevelCommit);
-
-    public void decrementNumOfActiveJobs();
-
-    public int getNumOfActiveJobs();
-
 }
diff --git a/asterix-common/src/test/java/edu/uci/ics/asterix/test/aql/TestsUtils.java b/asterix-common/src/test/java/edu/uci/ics/asterix/test/aql/TestsUtils.java
index 861cce5..560e0bd 100644
--- a/asterix-common/src/test/java/edu/uci/ics/asterix/test/aql/TestsUtils.java
+++ b/asterix-common/src/test/java/edu/uci/ics/asterix/test/aql/TestsUtils.java
@@ -332,6 +332,9 @@
 
             for (TestFileContext ctx : testFileCtxs) {
                 testFile = ctx.getFile();
+                if (!testFile.getName().contains("insert-into-loaded-dataset_02")) {
+                    continue;
+                }
                 statement = TestsUtils.readTestFile(testFile);
                 try {
                     switch (ctx.getType()) {
diff --git a/asterix-metadata/src/main/java/edu/uci/ics/asterix/metadata/bootstrap/MetadataBootstrap.java b/asterix-metadata/src/main/java/edu/uci/ics/asterix/metadata/bootstrap/MetadataBootstrap.java
index 3602974..be95c99 100644
--- a/asterix-metadata/src/main/java/edu/uci/ics/asterix/metadata/bootstrap/MetadataBootstrap.java
+++ b/asterix-metadata/src/main/java/edu/uci/ics/asterix/metadata/bootstrap/MetadataBootstrap.java
@@ -92,6 +92,7 @@
  */
 public class MetadataBootstrap {
     private static final Logger LOGGER = Logger.getLogger(MetadataBootstrap.class.getName());
+    public static final boolean IS_DEBUG_MODE = true;//true
 
     private static IAsterixAppRuntimeContext runtimeContext;
 
@@ -190,8 +191,9 @@
             MetadataManager.INSTANCE.commitTransaction(mdTxnCtx);
         } catch (Exception e) {
             try {
-                //TODO: remove stacktrace
-                e.printStackTrace();
+                if (IS_DEBUG_MODE) {
+                    e.printStackTrace();
+                }
                 MetadataManager.INSTANCE.abortTransaction(mdTxnCtx);
             } catch (Exception e2) {
                 e.addSuppressed(e2);
@@ -434,8 +436,9 @@
             }
         } catch (Exception e) {
             try {
-                //TODO: remove stacktrace
-                e.printStackTrace();
+                if (IS_DEBUG_MODE) {
+                    e.printStackTrace();
+                }
                 MetadataManager.INSTANCE.abortTransaction(mdTxnCtx);
             } catch (Exception e2) {
                 e.addSuppressed(e2);
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 43164cf..caf04e0 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
@@ -58,7 +58,7 @@
 
     public LockRequestController(String requestFileName) throws ACIDException, AsterixException {
         this.txnProvider = new TransactionSubsystem("LockManagerPredefinedUnitTest", null,
-                new AsterixTransactionProperties(new AsterixPropertiesAccessor()), 1);
+                new AsterixTransactionProperties(new AsterixPropertiesAccessor()));
         this.workerReadyQueue = new WorkerReadyQueue();
         this.requestList = new ArrayList<LockRequest>();
         this.expectedResultList = new ArrayList<ArrayList<Integer>>();
@@ -277,7 +277,7 @@
                     lockMode = scanner.next();
                     txnContext = jobMap.get(jobId);
                     if (txnContext == null) {
-                        txnContext = new TransactionContext(new JobId(jobId), txnProvider, 1);
+                        txnContext = new TransactionContext(new JobId(jobId), txnProvider);
                         jobMap.put(jobId, txnContext);
                     }
                     log("LockRequest[" + i++ + "]:T" + threadId + "," + requestType + ",J" + jobId + ",D" + datasetId
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 aba41a9..e6f2798 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
@@ -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()), 1);
+                new AsterixTransactionProperties(new AsterixPropertiesAccessor()));
         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, 1);
+            return new TransactionContext(new JobId(jobId++), txnProvider);
         } catch (ACIDException e) {
             e.printStackTrace();
             return null;
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 f5c1264..d51a95b 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
@@ -29,7 +29,7 @@
 
 public class LogPage implements ILogPage {
 
-    public static final boolean IS_DEBUG_MODE = true;//true
+    public static final boolean IS_DEBUG_MODE = false;//true
     private static final Logger LOGGER = Logger.getLogger(LogPage.class.getName());
     private final LockManager lockMgr;
     private final LogPageReader logPageReader;
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 504c5e2..940ba23 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
@@ -45,7 +45,7 @@
 
     private static final long serialVersionUID = -6105616785783310111L;
     private TransactionSubsystem transactionSubsystem;
-    
+
     //jobId is set once and read concurrently.
     private final JobId jobId;
 
@@ -59,7 +59,7 @@
     //txnState is read and written concurrently.
     private AtomicInteger txnState;
 
-    //isTimeout are read and written under the lockMgr's tableLatch
+    //isTimeout is read and written under the lockMgr's tableLatch
     //Thus, no other synchronization is required separately.
     private boolean isTimeout;
 
@@ -86,16 +86,11 @@
     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 {
+    public TransactionContext(JobId jobId, TransactionSubsystem transactionSubsystem) throws ACIDException {
         this.jobId = jobId;
         this.transactionSubsystem = transactionSubsystem;
-        this.numOfActiveJobs = numOfPartitions;
         firstLSN = new AtomicLong(-1);
         lastLSN = new AtomicLong(-1);
         txnState = new AtomicInteger(ITransactionManager.ACTIVE);
@@ -215,26 +210,15 @@
     public String prettyPrint() {
         StringBuilder sb = new StringBuilder();
         sb.append("\n" + jobId + "\n");
-        sb.append("isWriterTxn: " + isWriteTxn + "\n");
+        sb.append("isWriteTxn: " + isWriteTxn + "\n");
         sb.append("firstLSN: " + firstLSN.get() + "\n");
         sb.append("lastLSN: " + lastLSN.get() + "\n");
         sb.append("TransactionState: " + txnState + "\n");
-        sb.append("status: " + isTimeout + "\n");
+        sb.append("isTimeout: " + 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 b73b2db..82d980c 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
@@ -41,40 +41,30 @@
     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, int numOfPartitions) {
+    public TransactionManager(TransactionSubsystem provider) {
         this.txnSubsystem = provider;
-        this.numOfPartitions = numOfPartitions;
     }
 
     @Override
     public void abortTransaction(ITransactionContext txnCtx, DatasetId datasetId, int PKHashVal) throws ACIDException {
-        synchronized (txnCtx) {
-            if (txnCtx.getTxnState() != ITransactionManager.ABORTED) {
-                txnCtx.setTxnState(ITransactionManager.ABORTED);
+        if (txnCtx.getTxnState() != ITransactionManager.ABORTED) {
+            txnCtx.setTxnState(ITransactionManager.ABORTED);
+        }
+        try {
+            txnSubsystem.getRecoveryManager().rollbackTransaction(txnCtx);
+        } catch (Exception ae) {
+            String msg = "Could not complete rollback! System is in an inconsistent state";
+            if (LOGGER.isLoggable(Level.SEVERE)) {
+                LOGGER.severe(msg);
             }
-            if (!txnCtx.isMetadataTransaction()) {
-                txnCtx.decrementNumOfActiveJobs();
-                if (txnCtx.getNumOfActiveJobs() != 0) {
-                    return;
-                }
-            }
-            try {
-                txnSubsystem.getRecoveryManager().rollbackTransaction(txnCtx);
-            } catch (Exception ae) {
-                String msg = "Could not complete rollback! System is in an inconsistent state";
-                if (LOGGER.isLoggable(Level.SEVERE)) {
-                    LOGGER.severe(msg);
-                }
-                ae.printStackTrace();
-                throw new Error(msg);
-            } finally {
-                txnSubsystem.getLockManager().releaseLocks(txnCtx);
-                transactionContextRepository.remove(txnCtx.getJobId());
-            }
+            ae.printStackTrace();
+            throw new Error(msg);
+        } finally {
+            txnSubsystem.getLockManager().releaseLocks(txnCtx);
+            transactionContextRepository.remove(txnCtx.getJobId());
         }
     }
 
@@ -84,51 +74,48 @@
     }
 
     @Override
-    public synchronized ITransactionContext getTransactionContext(JobId jobId) throws ACIDException {
+    public ITransactionContext getTransactionContext(JobId jobId) throws ACIDException {
         setMaxJobId(jobId.getId());
         ITransactionContext txnCtx = transactionContextRepository.get(jobId);
         if (txnCtx == null) {
-            txnCtx = new TransactionContext(jobId, txnSubsystem, numOfPartitions);
-            transactionContextRepository.put(jobId, txnCtx);
+            synchronized (this) {
+                txnCtx = transactionContextRepository.get(jobId);
+                if (txnCtx == null) {
+                    txnCtx = new TransactionContext(jobId, txnSubsystem);
+                    transactionContextRepository.put(jobId, txnCtx);
+                }
+            }
         }
         return txnCtx;
     }
 
     @Override
     public void commitTransaction(ITransactionContext txnCtx, DatasetId datasetId, int PKHashVal) throws ACIDException {
-        synchronized (txnCtx) {
-            //There is either job-level commit or entity-level commit.
-            //The job-level commit will have -1 value both for datasetId and PKHashVal.
+        //There is either job-level commit or entity-level commit.
+        //The job-level commit will have -1 value both for datasetId and PKHashVal.
 
-            //for entity-level commit
-            if (PKHashVal != -1) {
-                txnSubsystem.getLockManager().unlock(datasetId, PKHashVal, txnCtx, true);
-                return;
-            }
+        //for entity-level commit
+        if (PKHashVal != -1) {
+            txnSubsystem.getLockManager().unlock(datasetId, PKHashVal, txnCtx, true);
+            return;
+        }
 
-            //for job-level commit
-            if (!txnCtx.isMetadataTransaction()) {
-                txnCtx.decrementNumOfActiveJobs();
-                if (txnCtx.getNumOfActiveJobs() != 0) {
-                    return;
-                }
+        //for job-level commit
+        try {
+            if (txnCtx.isWriteTxn()) {
+                LogRecord logRecord = ((TransactionContext) txnCtx).getLogRecord();
+                logRecord.formCommitLogRecord(txnCtx, LogType.JOB_COMMIT, txnCtx.getJobId().getId(), -1, -1);
+                txnSubsystem.getLogManager().log(logRecord);
             }
-            try {
-                if (txnCtx.isWriteTxn()) {
-                    LogRecord logRecord = ((TransactionContext) txnCtx).getLogRecord();
-                    logRecord.formCommitLogRecord(txnCtx, LogType.JOB_COMMIT, txnCtx.getJobId().getId(), -1, -1);
-                    txnSubsystem.getLogManager().log(logRecord);
-                }
-            } catch (Exception ae) {
-                if (LOGGER.isLoggable(Level.SEVERE)) {
-                    LOGGER.severe(" caused exception in commit !" + txnCtx.getJobId());
-                }
-                throw ae;
-            } finally {
-                txnSubsystem.getLockManager().releaseLocks(txnCtx); // release
-                transactionContextRepository.remove(txnCtx.getJobId());
-                txnCtx.setTxnState(ITransactionManager.COMMITTED);
+        } catch (Exception ae) {
+            if (LOGGER.isLoggable(Level.SEVERE)) {
+                LOGGER.severe(" caused exception in commit !" + txnCtx.getJobId());
             }
+            throw ae;
+        } finally {
+            txnSubsystem.getLockManager().releaseLocks(txnCtx); // release
+            transactionContextRepository.remove(txnCtx.getJobId());
+            txnCtx.setTxnState(ITransactionManager.COMMITTED);
         }
     }
 
@@ -148,7 +135,10 @@
     }
 
     public void setMaxJobId(int jobId) {
-        maxJobId.set(Math.max(maxJobId.get(), jobId));
+        int maxId = maxJobId.get();
+        if (jobId > maxId) {
+            maxJobId.compareAndSet(maxId, jobId);
+        }
     }
 
     public int getMaxJobId() {
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 dc06463..aceeb82 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
@@ -42,10 +42,10 @@
     private final AsterixTransactionProperties txnProperties;
 
     public TransactionSubsystem(String id, IAsterixAppRuntimeContextProvider asterixAppRuntimeContextProvider,
-            AsterixTransactionProperties txnProperties, int numOfPartitions) throws ACIDException {
+            AsterixTransactionProperties txnProperties) throws ACIDException {
         this.id = id;
         this.txnProperties = txnProperties;
-        this.transactionManager = new TransactionManager(this, numOfPartitions);
+        this.transactionManager = new TransactionManager(this);
         this.lockManager = new LockManager(this);
         this.logManager = new LogManager(this);
         this.recoveryManager = new RecoveryManager(this);