Merge -r 584823:58424 from trunk to branch 15 to fix HADOOP-2053.

git-svn-id: https://svn.apache.org/repos/asf/lucene/hadoop/branches/branch-0.15@584851 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -415,6 +415,12 @@ Branch 0.15 (unreleased changes)
     edits log. Reduce the number of syncs by double-buffering the changes
     to the transaction log. (Dhruba Borthakur)
 
+Release 0.14.3 - Unreleased
+
+  BUG FIXES
+
+    HADOOP-2053. Fixed a dangling reference to a memory buffer in the map 
+    output sorter. (acmurthy via omalley)
 
     HADOOP-2036. Fix a NullPointerException in JvmMetrics class. (nigel)
 

src/java/org/apache/hadoop/mapred/BasicTypeSorterBase.java

@@ -120,6 +120,10 @@ abstract class BasicTypeSorterBase implements BufferSorter {
     pointers = null;
     maxKeyLength = 0;
     maxValLength = 0;
+    
+    //release the large key-value buffer so that the GC, if necessary,
+    //can collect it away
+    keyValBuffer = null;
   }
   //A compare method that references the keyValBuffer through the indirect
   //pointers