svn commit: r573513 - in /lucene/hadoop/trunk: CHANGES.txt src/java/org/apache/hadoop/mapred/JobTracker.java

[ac...@apache.org]

Author: acmurthy
Date: Fri Sep  7 02:09:00 2007
New Revision: 573513

URL: http://svn.apache.org/viewvc?rev=573513&view=rev
Log:
HADOOP-1018.  Improve documentation w.r.t handling of lost hearbeats between TaskTrackers and JobTracker.

Modified:
    lucene/hadoop/trunk/CHANGES.txt
    lucene/hadoop/trunk/src/java/org/apache/hadoop/mapred/JobTracker.java

Modified: lucene/hadoop/trunk/CHANGES.txt
URL: http://svn.apache.org/viewvc/lucene/hadoop/trunk/CHANGES.txt?rev=573513&r1=573512&r2=573513&view=diff
==============================================================================
--- lucene/hadoop/trunk/CHANGES.txt (original)
+++ lucene/hadoop/trunk/CHANGES.txt Fri Sep  7 02:09:00 2007
@@ -174,6 +174,9 @@
     code in Hadoop so that you can copy from and to all of the supported file 
     systems.(Chris Douglas via omalley)
 
+    HADOOP-1018.  Improve documentation w.r.t handling of lost hearbeats between 
+    TaskTrackers and JobTracker. (acmurthy)
+
 Release 0.14.1 - 2007-09-04
 
   BUG FIXES

Modified: lucene/hadoop/trunk/src/java/org/apache/hadoop/mapred/JobTracker.java
URL: http://svn.apache.org/viewvc/lucene/hadoop/trunk/src/java/org/apache/hadoop/mapred/JobTracker.java?rev=573513&r1=573512&r2=573513&view=diff
==============================================================================
--- lucene/hadoop/trunk/src/java/org/apache/hadoop/mapred/JobTracker.java (original)
+++ lucene/hadoop/trunk/src/java/org/apache/hadoop/mapred/JobTracker.java Fri Sep  7 02:09:00 2007
@@ -1101,13 +1101,14 @@
 
       }
                 
-      // It is completely safe to ignore a 'duplicate' from a tracker
-      // since we are guaranteed that the tracker sends the same 
-      // 'heartbeat' when rpcs are lost. 
-      // {@see TaskTracker.transmitHeartbeat()}
+      // It is completely safe to not process a 'duplicate' heartbeat from a 
+      // {@link TaskTracker} since it resends the heartbeat when rpcs are lost - 
+      // @see {@link TaskTracker.transmitHeartbeat()};
+      // acknowledge it by re-sending the previous response to let the 
+      // {@link TaskTracker} go forward. 
       if (prevHeartbeatResponse.getResponseId() != responseId) {
         LOG.info("Ignoring 'duplicate' heartbeat from '" + 
-                 trackerName + "'");
+                 trackerName + "'; resending the previous 'lost' response");
         return prevHeartbeatResponse;
       }
     }