diff --git a/hyracks-api/src/main/java/edu/uci/ics/hyracks/api/context/ICCContext.java b/hyracks-api/src/main/java/edu/uci/ics/hyracks/api/context/ICCContext.java
index 266ebe9..abd9c20 100644
--- a/hyracks-api/src/main/java/edu/uci/ics/hyracks/api/context/ICCContext.java
+++ b/hyracks-api/src/main/java/edu/uci/ics/hyracks/api/context/ICCContext.java
@@ -18,5 +18,5 @@
 import java.util.Set;
 
 public interface ICCContext {
-    public Map<String, Set<String>> getIPAddressNodeMap();
+    public void getIPAddressNodeMap(Map<String, Set<String>> map) throws Exception;
 }
\ No newline at end of file
diff --git a/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/ClusterControllerService.java b/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/ClusterControllerService.java
index 4575adc..fd401b4 100644
--- a/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/ClusterControllerService.java
+++ b/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/ClusterControllerService.java
@@ -46,6 +46,7 @@
 import edu.uci.ics.hyracks.control.cc.work.ApplicationCreateWork;
 import edu.uci.ics.hyracks.control.cc.work.ApplicationDestroyWork;
 import edu.uci.ics.hyracks.control.cc.work.ApplicationStartWork;
+import edu.uci.ics.hyracks.control.cc.work.GetIpAddressNodeNameMapWork;
 import edu.uci.ics.hyracks.control.cc.work.GetJobStatusConditionVariableWork;
 import edu.uci.ics.hyracks.control.cc.work.GetJobStatusWork;
 import edu.uci.ics.hyracks.control.cc.work.GetNodeControllersInfoWork;
@@ -149,8 +150,9 @@
         this.timer = new Timer(true);
         ccContext = new ICCContext() {
             @Override
-            public Map<String, Set<String>> getIPAddressNodeMap() {
-                return ipAddressNodeNameMap;
+            public void getIPAddressNodeMap(Map<String, Set<String>> map) throws Exception {
+                GetIpAddressNodeNameMapWork ginmw = new GetIpAddressNodeNameMapWork(ClusterControllerService.this, map);
+                workQueue.scheduleAndSync(ginmw);
             }
         };
         sweeper = new DeadNodeSweeper();
@@ -201,6 +203,10 @@
     public Map<JobId, JobRun> getRunMapArchive() {
         return runMapArchive;
     }
+    
+    public Map<String, Set<String>> getIpAddressNodeNameMap() {
+        return ipAddressNodeNameMap;
+    }
 
     public LogFile getJobLogFile() {
         return jobLog;
@@ -237,7 +243,6 @@
 
     @Override
     public NodeParameters registerNode(NodeRegistration reg) throws Exception {
-        InetSocketAddress ncAddress = reg.getNodeControllerAddress();
         String id = reg.getNodeId();
 
         IIPCHandle ncIPCHandle = clusterIPC.getHandle(reg.getNodeControllerAddress());
diff --git a/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/scheduler/JobScheduler.java b/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/scheduler/JobScheduler.java
index e2c9ca3..5e11470 100644
--- a/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/scheduler/JobScheduler.java
+++ b/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/scheduler/JobScheduler.java
@@ -309,6 +309,10 @@
                 }
             }
             aggregateRunnability = Runnability.getWorstCase(aggregateRunnability, runnability);
+            if (aggregateRunnability.getTag() == Runnability.Tag.NOT_RUNNABLE) {
+                // already not runnable -- cannot get better. bail.
+                break;
+            }
             if (LOGGER.isLoggable(Level.INFO)) {
                 LOGGER.info("aggregateRunnability: " + aggregateRunnability);
             }
diff --git a/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/work/GetIpAddressNodeNameMapWork.java b/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/work/GetIpAddressNodeNameMapWork.java
new file mode 100644
index 0000000..ed18b21
--- /dev/null
+++ b/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/work/GetIpAddressNodeNameMapWork.java
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2009-2010 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.hyracks.control.cc.work;
+
+import java.util.Map;
+import java.util.Set;
+
+import edu.uci.ics.hyracks.control.cc.ClusterControllerService;
+import edu.uci.ics.hyracks.control.common.work.SynchronizableWork;
+
+public class GetIpAddressNodeNameMapWork extends SynchronizableWork {
+    private final ClusterControllerService ccs;
+    private Map<String, Set<String>> map;
+
+    public GetIpAddressNodeNameMapWork(ClusterControllerService ccs, Map<String, Set<String>> map) {
+        this.ccs = ccs;
+    }
+
+    @Override
+    protected void doRun() throws Exception {
+        map.putAll(ccs.getIpAddressNodeNameMap());
+    }
+}
\ No newline at end of file
diff --git a/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/work/RegisterNodeWork.java b/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/work/RegisterNodeWork.java
index 15daff5..e65b1de 100644
--- a/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/work/RegisterNodeWork.java
+++ b/hyracks-control-cc/src/main/java/edu/uci/ics/hyracks/control/cc/work/RegisterNodeWork.java
@@ -14,7 +14,9 @@
  */
 package edu.uci.ics.hyracks.control.cc.work;
 
+import java.util.HashSet;
 import java.util.Map;
+import java.util.Set;
 
 import edu.uci.ics.hyracks.control.cc.ClusterControllerService;
 import edu.uci.ics.hyracks.control.cc.NodeControllerState;
@@ -38,5 +40,13 @@
             throw new Exception("Node with this name already registered.");
         }
         nodeMap.put(nodeId, state);
+        Map<String, Set<String>> ipAddressNodeNameMap = ccs.getIpAddressNodeNameMap();
+        String ipAddress = state.getNCConfig().dataIPAddress;
+        Set<String> nodes = ipAddressNodeNameMap.get(ipAddress);
+        if (nodes == null) {
+            nodes = new HashSet<String>();
+            ipAddressNodeNameMap.put(ipAddress, nodes);
+        }
+        nodes.add(nodeId);
     }
 }
\ No newline at end of file