diff --git a/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/dataset/DatasetPartitionReader.java b/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/dataset/DatasetPartitionReader.java
index 7b2b30a..296c502 100644
--- a/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/dataset/DatasetPartitionReader.java
+++ b/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/dataset/DatasetPartitionReader.java
@@ -85,7 +85,7 @@
                 NetworkOutputChannel channel = (NetworkOutputChannel) writer;
                 channel.setFrameSize(resultState.getFrameSize());
                 try {
-                    fileHandle = resultState.getIOManager().open(resultState.getFileReference(),
+                    fileHandle = resultState.getIOManager().open(resultState.getValidFileReference(),
                             IIOManager.FileReadWriteMode.READ_ONLY, IIOManager.FileSyncMode.METADATA_ASYNC_DATA_ASYNC);
                     channel.open();
                     try {
@@ -108,6 +108,8 @@
                         channel.close();
                         resultState.getIOManager().close(fileHandle);
                     }
+                } catch (InterruptedException e) {
+                    throw new RuntimeException(e);
                 } catch (HyracksDataException e) {
                     throw new RuntimeException(e);
                 }
diff --git a/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/dataset/ResultState.java b/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/dataset/ResultState.java
index d2e86bc..3db3fd9 100644
--- a/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/dataset/ResultState.java
+++ b/hyracks/hyracks-control/hyracks-control-nc/src/main/java/edu/uci/ics/hyracks/control/nc/dataset/ResultState.java
@@ -56,11 +56,12 @@
         localPageList = new ArrayList<Page>();
     }
 
-    public void init(FileReference fileRef) {
+    public synchronized void init(FileReference fileRef) {
         this.fileRef = fileRef;
 
         size = 0;
         persistentSize = 0;
+        notifyAll();
     }
 
     public ResultSetPartitionId getResultSetPartitionId() {
@@ -139,7 +140,9 @@
         return page;
     }
 
-    public FileReference getFileReference() {
+    public synchronized FileReference getValidFileReference() throws InterruptedException {
+        while (fileRef == null)
+            wait();
         return fileRef;
     }