MAPREDUCE-1906. Lower minimum heartbeat interval between tasktracker and JobTracker for smaller clusters. (Contributed by Todd Lipcon, backport by Brandon Li)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-1@1366285 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -51,7 +51,12 @@ Release 1.2.0 - unreleased
 
     HDFS-496. Backport: Use PureJavaCrc32 in HDFS.  (Brandon Li via szetszwo)
 
-    MAPREDUCE-782. Use PureJavaCrc32 in mapreduce spills. (Todd Lipcon, backport by Brandon Li via sseth)
+    MAPREDUCE-782. Use PureJavaCrc32 in mapreduce spills. 
+    (Todd Lipcon, backport by Brandon Li via sseth)
+
+    MAPREDUCE-1906. Lower minimum heartbeat interval between tasktracker and 
+    JobTracker for smaller clusters. (Todd Lipcon, backport by 
+    Brandon Li via sseth)
 
   OPTIMIZATIONS
 

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

@@ -3142,7 +3142,7 @@ public class JobTracker implements MRConstants, InterTrackerProtocol,
     int clusterSize = getClusterStatus().getTaskTrackers();
     int heartbeatInterval =  Math.max(
                                 (int)(1000 * HEARTBEATS_SCALING_FACTOR *
-                                      Math.ceil((double)clusterSize / 
+                                      ((double)clusterSize / 
                                                 NUM_HEARTBEATS_IN_SECOND)),
                                 HEARTBEAT_INTERVAL_MIN) ;
     return heartbeatInterval;

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

@@ -25,7 +25,7 @@ interface MRConstants {
   //
   // Timeouts, constants
   //
-  public static final int HEARTBEAT_INTERVAL_MIN = 3 * 1000;
+  public static final int HEARTBEAT_INTERVAL_MIN = 300;
   
   public static final long COUNTER_UPDATE_INTERVAL = 60 * 1000;