HADOOP-11323. WritableComparator#compare keeps reference to byte array. Contributed by Wilfred Spiegelenburg.

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -394,6 +394,9 @@ Release 2.7.0 - UNRELEASED
 
   OPTIMIZATIONS
 
+    HADOOP-11323. WritableComparator#compare keeps reference to byte array.
+    (Wilfred Spiegelenburg via wang)
+
   BUG FIXES
 
     HADOOP-11236. NFS: Fix javadoc warning in RpcProgram.java (Abhiraj Butala via harsh)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/WritableComparator.java

@@ -160,6 +160,7 @@ public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
       buffer.reset(b2, s2, l2);                   // parse key2
       key2.readFields(buffer);
       
+      buffer.reset(null, 0, 0);                   // clean up reference
     } catch (IOException e) {
       throw new RuntimeException(e);
     }