diff --git a/CHANGES.txt b/CHANGES.txt
index 0356b75..a91aa7f 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -6,6 +6,7 @@
 INCOMPATIBLE CHANGES
 
 ALL CHANGES:
+  TEZ-2907. NPE in IFile.Reader.getLength during final merge operation
   TEZ-2850. Tez MergeManager OOM for small Map Outputs
   TEZ-2781. Fallback to send only TaskAttemptFailedEvent if taskFailed heartbeat fails
   TEZ-2855. Fix a potential NPE while routing VertexManager events.
diff --git a/tez-runtime-library/src/main/java/org/apache/tez/runtime/library/common/shuffle/orderedgrouped/MergeManager.java b/tez-runtime-library/src/main/java/org/apache/tez/runtime/library/common/shuffle/orderedgrouped/MergeManager.java
index efecb8a..f498787 100644
--- a/tez-runtime-library/src/main/java/org/apache/tez/runtime/library/common/shuffle/orderedgrouped/MergeManager.java
+++ b/tez-runtime-library/src/main/java/org/apache/tez/runtime/library/common/shuffle/orderedgrouped/MergeManager.java
@@ -812,12 +812,14 @@
   class RawKVIteratorReader extends IFile.Reader {
 
     private final TezRawKeyValueIterator kvIter;
+    private final long size;
 
     public RawKVIteratorReader(TezRawKeyValueIterator kvIter, long size)
         throws IOException {
       super(null, size, null, spilledRecordsCounter, null, ifileReadAhead,
           ifileReadAheadLength, ifileBufferSize);
       this.kvIter = kvIter;
+      this.size = size;
     }
     @Override
     public KeyState readRawKey(DataInputBuffer key) throws IOException {
@@ -845,6 +847,10 @@
     public void close() throws IOException {
       kvIter.close();
     }
+
+    @Override public long getLength() {
+      return size;
+    }
   }
 
   private TezRawKeyValueIterator finalMerge(Configuration job, FileSystem fs,