diff --git a/asterix-maven-plugins/record-manager-generator-maven-plugin/src/main/java/edu/uci/ics/asterix/recordmanagergenerator/RecordType.java b/asterix-maven-plugins/record-manager-generator-maven-plugin/src/main/java/edu/uci/ics/asterix/recordmanagergenerator/RecordType.java
index 6d31f63..2ffa8be 100644
--- a/asterix-maven-plugins/record-manager-generator-maven-plugin/src/main/java/edu/uci/ics/asterix/recordmanagergenerator/RecordType.java
+++ b/asterix-maven-plugins/record-manager-generator-maven-plugin/src/main/java/edu/uci/ics/asterix/recordmanagergenerator/RecordType.java
@@ -110,7 +110,7 @@
               .append("(long slotNum) {\n");
             if (initial != null) {
               sb = indent(sb, indent, level + 1);
-              sb.append("if (TRACK_ALLOC) checkSlot(slotNum);\n");
+              sb.append("if (TRACK_ALLOC_ID) checkAllocId(slotNum);\n");
             }
             sb = indent(sb, indent, level + 1);
             sb.append("final int arenaId = RecordManagerTypes.Global.arenaId(slotNum);\n");
@@ -134,7 +134,7 @@
               .append(" value) {\n");
             if (initial != null) {
               sb = indent(sb, indent, level + 1);
-              sb.append("if (TRACK_ALLOC) checkSlot(slotNum);\n");
+              sb.append("if (TRACK_ALLOC_ID) checkAllocId(slotNum);\n");
             }
             sb = indent(sb, indent, level + 1);
             sb.append("final int arenaId = RecordManagerTypes.Global.arenaId(slotNum);\n");
diff --git a/asterix-maven-plugins/record-manager-generator-maven-plugin/src/main/resources/ArenaManager.java b/asterix-maven-plugins/record-manager-generator-maven-plugin/src/main/resources/ArenaManager.java
index 58f8972..6d77b51 100644
--- a/asterix-maven-plugins/record-manager-generator-maven-plugin/src/main/resources/ArenaManager.java
+++ b/asterix-maven-plugins/record-manager-generator-maven-plugin/src/main/resources/ArenaManager.java
@@ -15,73 +15,67 @@
 
 package edu.uci.ics.asterix.transaction.management.service.locking;
 
-import java.util.ArrayList;
-
 import edu.uci.ics.asterix.transaction.management.service.locking.AllocInfo;
 import edu.uci.ics.asterix.transaction.management.service.locking.RecordManagerTypes;
 
 public class @E@ArenaManager {
     
-    public static final boolean TRACK_ALLOC = @DEBUG@;
+    public static final boolean TRACK_ALLOC_ID = @DEBUG@;
 
     private final int noArenas;
-    private final long txnShrinkTimer;
-    private ArrayList<@E@RecordManager> arenas;
-    private volatile int nextArena; 
-    private ThreadLocal<LocalManager> local;    
+    private final @E@RecordManager[] arenas;
+    private ThreadLocal<LocalManager> local;
     
-    public @E@ArenaManager(long txnShrinkTimer) {
-        this.txnShrinkTimer = txnShrinkTimer;
-        noArenas = Runtime.getRuntime().availableProcessors() * 2;
-        arenas = new ArrayList<@E@RecordManager>(noArenas);
-        nextArena = 0;
+    static class LocalManager {
+        int arenaId;
+        @E@RecordManager mgr;
+    }
+    
+    public @E@ArenaManager(final int noArenas, final long txnShrinkTimer) {
+        this.noArenas = noArenas;
+        arenas = new @E@RecordManager[noArenas];
+        for (int i = 0; i < noArenas; ++i) {
+            arenas[i] = new @E@RecordManager(txnShrinkTimer);
+        }
         local = new ThreadLocal<LocalManager>() {
+            private int nextArena = 0; 
+
             @Override
-            protected LocalManager initialValue() {
-                return getNext();
+            protected synchronized LocalManager initialValue() {
+                @E@RecordManager mgr = arenas[nextArena];
+                LocalManager res = new LocalManager();
+                res.mgr = mgr;
+                res.arenaId = nextArena;
+                nextArena = (nextArena + 1) % noArenas;
+                return res;
             }
         };
     }
 
     public long allocate() {
         final LocalManager localManager = local.get();
-        long result = localManager.arenaId;
-        result = result << 48;
-        final int localId = localManager.mgr.allocate();
-        result |= localId;
-        if (TRACK_ALLOC) {
-            final long allocId = (++localManager.mgr.allocCounter % 0x7fff);
-            result |= (allocId << 32);
-            setAllocId(result, (short) allocId);
-            assert RecordManagerTypes.Global.allocId(result) == allocId;
-        }
+        final @E@RecordManager recMgr = localManager.mgr;
+        final int allocId = TRACK_ALLOC_ID ? (++recMgr.allocCounter % 0x7fff) : 0;
+        final int localId = recMgr.allocate();
+        
+        long result = RecordManagerTypes.Global.build(localManager.arenaId, allocId, localId);
+
+        if (TRACK_ALLOC_ID) setAllocId(result, (short) allocId);
+
+        assert RecordManagerTypes.Global.allocId(result) == allocId;
         assert RecordManagerTypes.Global.arenaId(result) == localManager.arenaId;
         assert RecordManagerTypes.Global.localId(result) == localId;
         return result;
     }
     
     public void deallocate(long slotNum) {
-        if (TRACK_ALLOC) {
-            checkSlot(slotNum);
-        }
+        if (TRACK_ALLOC_ID) checkAllocId(slotNum);
         final int arenaId = RecordManagerTypes.Global.arenaId(slotNum);
         get(arenaId).deallocate(RecordManagerTypes.Global.localId(slotNum));
     }
     
-    public synchronized LocalManager getNext() {
-        if (nextArena >= arenas.size()) { 
-            arenas.add(new @E@RecordManager(txnShrinkTimer));
-        }
-        @E@RecordManager mgr = arenas.get(nextArena);
-        LocalManager res = new LocalManager();
-        res.mgr = mgr;
-        res.arenaId = nextArena;
-        nextArena = (nextArena + 1) % noArenas;
-        return res;
-    }
-    
     public @E@RecordManager get(int i) {
-        return arenas.get(i);
+        return arenas[i];
     }
     
     public @E@RecordManager local() {
@@ -90,7 +84,7 @@
     
     @METHODS@
     
-    private void checkSlot(long slotNum) {
+    private void checkAllocId(long slotNum) {
         final int refAllocId = RecordManagerTypes.Global.allocId(slotNum);
         final short curAllocId = getAllocId(slotNum);
         if (refAllocId != curAllocId) {
@@ -111,15 +105,10 @@
         return get(arenaId).getAllocInfo(RecordManagerTypes.Global.localId(slotNum));
     }
     
-    static class LocalManager {
-        int arenaId;
-        @E@RecordManager mgr;
-    }
-    
     public StringBuilder append(StringBuilder sb) {
-        for (int i = 0; i < arenas.size(); ++i) {
+        for (int i = 0; i < noArenas; ++i) {
             sb.append("++++ arena ").append(i).append(" ++++\n");
-            arenas.get(i).append(sb);
+            arenas[i].append(sb);
         }
         return sb;
     }
@@ -129,10 +118,9 @@
     }
 
     public Stats addTo(Stats s) {
-        final int size = arenas.size();
-        s.arenas += size;
-        for (int i = 0; i < size; ++i) {
-            arenas.get(i).addTo(s);
+        s.arenas += noArenas;
+        for (int i = 0; i < noArenas; ++i) {
+            arenas[i].addTo(s);
         }
         return s;
     }
diff --git a/asterix-maven-plugins/record-manager-generator-maven-plugin/src/main/resources/RecordManager.java b/asterix-maven-plugins/record-manager-generator-maven-plugin/src/main/resources/RecordManager.java
index 01049d3..6aa26f4 100644
--- a/asterix-maven-plugins/record-manager-generator-maven-plugin/src/main/resources/RecordManager.java
+++ b/asterix-maven-plugins/record-manager-generator-maven-plugin/src/main/resources/RecordManager.java
@@ -23,7 +23,8 @@
 
 public class @E@RecordManager {
 
-    public static final boolean TRACK_ALLOC = @DEBUG@;
+    public static final boolean CHECK_SLOTS = @DEBUG@;
+    public static final boolean TRACK_ALLOC_LOC = @DEBUG@;
     
     static final int NO_SLOTS = 10;
 
@@ -47,23 +48,39 @@
         allocCounter = 0;
     }
     
+    enum SlotSource {
+        NON_FULL,
+        UNINITIALIZED,
+        NEW
+    }
+    
     synchronized int allocate() {
         if (buffers.get(current).isFull()) {
-            int size = buffers.size();
-            boolean needNewBuffer = true;
-            for (int i = 0; i < size; i++) {
-                Buffer buffer = buffers.get(i);
-                if (! buffer.isInitialized()) {
-                    buffer.initialize();
+            final int size = buffers.size();
+            SlotSource source = SlotSource.NEW;
+            for (int i = 0; i < size; ++i) {
+                // If we find a buffer with space, we use it. Otherwise we
+                // remember the first uninitialized one and use that one.
+                final Buffer buffer = buffers.get(i);
+                if (buffer.isInitialized() && ! buffer.isFull()) {
+                    source = SlotSource.NON_FULL;
                     current = i;
-                    needNewBuffer = false;
                     break;
+                } else if (! buffer.isInitialized() && source == SlotSource.NEW) {
+                    source = SlotSource.UNINITIALIZED;
+                    current = i;
                 }
             }
-
-            if (needNewBuffer) {
-                buffers.add(new Buffer());
-                current = buffers.size() - 1;
+            
+            switch (source) {
+                case NEW:
+                    buffers.add(new Buffer());
+                    current = buffers.size() - 1;
+                    break;
+                case UNINITIALIZED:
+                    buffers.get(current).initialize();
+                case NON_FULL:
+                    break;
             }
         }
         ++occupiedSlots;
@@ -202,9 +219,9 @@
     }
     
     static class Buffer {
-        private ByteBuffer bb;
+        private ByteBuffer bb = null; // null represents 'deinitialized' state.
         private int freeSlotNum;
-        private int occupiedSlots = -1; //-1 represents 'deinitialized' state.
+        private int occupiedSlots;
         
         ArrayList<AllocInfo> allocList;
         
@@ -222,7 +239,7 @@
             }
             setNextFreeSlot(NO_SLOTS - 1, -1); //-1 represents EOL(end of link)
             
-            if (TRACK_ALLOC) {
+            if (TRACK_ALLOC_LOC) {
                 allocList = new ArrayList<AllocInfo>(NO_SLOTS);
                 for (int i = 0; i < NO_SLOTS; ++i) {
                     allocList.add(new AllocInfo());
@@ -231,16 +248,16 @@
         }
         
         public void deinitialize() {
+            if (TRACK_ALLOC_LOC) allocList = null;
             bb = null;
-            occupiedSlots = -1;
         }
         
         public boolean isInitialized() {
-            return occupiedSlots >= 0;
+            return bb != null;
         }
 
         public boolean isFull() {
-            return occupiedSlots == NO_SLOTS;
+            return freeSlotNum == -1;
         }
 
         public boolean isEmpty() {
@@ -252,7 +269,7 @@
             freeSlotNum = getNextFreeSlot(slotNum);
             @INIT_SLOT@
             occupiedSlots++;
-            if (TRACK_ALLOC) allocList.get(slotNum).alloc();
+            if (TRACK_ALLOC_LOC) allocList.get(slotNum).alloc();
             return slotNum;
         }
     
@@ -261,7 +278,7 @@
             setNextFreeSlot(slotNum, freeSlotNum);
             freeSlotNum = slotNum;
             occupiedSlots--;
-            if (TRACK_ALLOC) allocList.get(slotNum).free();
+            if (TRACK_ALLOC_LOC) allocList.get(slotNum).free();
         }
 
         public int getNextFreeSlot(int slotNum) {
@@ -293,7 +310,7 @@
         }
         
         private void checkSlot(int slotNum) {
-            if (! TRACK_ALLOC) {
+            if (! CHECK_SLOTS) {
                 return;
             }
             final int itemOffset = (slotNum % NO_SLOTS) * ITEM_SIZE;
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 80da1ab..8a8194a 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
@@ -76,9 +76,11 @@
         final int lockManagerShrinkTimer = txnSubsystem.getTransactionProperties()
                 .getLockManagerShrinkTimer();
 
-        resArenaMgr = new ResourceArenaManager(lockManagerShrinkTimer);
-        reqArenaMgr = new RequestArenaManager(lockManagerShrinkTimer);
-        jobArenaMgr = new JobArenaManager(lockManagerShrinkTimer);
+        int noArenas = Runtime.getRuntime().availableProcessors() * 2;
+
+        resArenaMgr = new ResourceArenaManager(noArenas, lockManagerShrinkTimer);
+        reqArenaMgr = new RequestArenaManager(noArenas, lockManagerShrinkTimer);
+        jobArenaMgr = new JobArenaManager(noArenas, lockManagerShrinkTimer);
         jobIdSlotMap = new ConcurrentHashMap<>();
         dsLockCache = new ThreadLocal<DatasetLockCache>() {
             protected DatasetLockCache initialValue() {
@@ -733,15 +735,26 @@
     private static class DatasetLockCache {
         private long jobId = -1;
         private HashMap<Integer,Byte> lockCache =  new HashMap<Integer,Byte>();
+        // size 1 cache to avoid the boxing/unboxing that comes with the 
+        // access to the HashMap
+        private int cDsId = -1;
+        private byte cDsLockMode = -1;
         
         public boolean contains(final int jobId, final int dsId, byte dsLockMode) {
             if (this.jobId == jobId) {
+                if (this.cDsId == dsId && this.cDsLockMode == dsLockMode) {
+                    return true;
+                }
                 final Byte cachedLockMode = this.lockCache.get(dsId);
                 if (cachedLockMode != null && cachedLockMode == dsLockMode) {
+                    this.cDsId = dsId;
+                    this.cDsLockMode = dsLockMode;
                     return true;
                 }            
             } else {
                 this.jobId = -1;
+                this.cDsId = -1;
+                this.cDsLockMode = -1;
                 this.lockCache.clear();
             }
             return false;
@@ -749,6 +762,8 @@
         
         public void put(final int jobId, final int dsId, byte dsLockMode) {
             this.jobId = jobId;
+            this.cDsId = dsId;
+            this.cDsLockMode = dsLockMode;
             this.lockCache.put(dsId, dsLockMode);
         }
         
diff --git a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/RecordManagerTypes.java b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/RecordManagerTypes.java
index b467cc3..27f2981 100644
--- a/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/RecordManagerTypes.java
+++ b/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/service/locking/RecordManagerTypes.java
@@ -22,6 +22,14 @@
 
     public static class Global {
 
+        public static long build(int arenaId, int allocId, int localId) {
+            long result = arenaId;
+            result = result << 48;
+            result |= (allocId << 32);
+            result |= localId;
+            return result;
+        }
+
         public static int arenaId(long l) {
             return (int)((l >>> 48) & 0xffff);
         }