MAPREDUCE-4662. JobHistoryFilesManager thread pool never expands (Kihwal Lee via tgraves)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-1@1389888 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -254,6 +254,9 @@ Release 1.2.0 - unreleased
     MAPREDUCE-4652. ValueAggregatorJob sets the wrong job jar.
     (Ahmed Radwan via tomwhite)
 
+    MAPREDUCE-4662.  JobHistoryFilesManager thread pool never expands 
+    (Kihwal Lee via tgraves)
+
 Release 1.1.0 - unreleased
 
   INCOMPATIBLE CHANGES

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

@@ -221,8 +221,11 @@ public class JobHistory {
 
 
     void start() {
-      executor = new ThreadPoolExecutor(1, 3, 1, 
+      executor = new ThreadPoolExecutor(5, 5, 1, 
           TimeUnit.HOURS, new LinkedBlockingQueue<Runnable>());
+      // make core threads to terminate if there has been no work
+      // for the keppalive period.
+      executor.allowCoreThreadTimeOut(true);
     }
 
     private FilesHolder getFileHolder(JobID id) {