[jira] [Commented] (MAPREDUCE-2237) Lost heartbeat response containing MapTask throws NPE when it is resent

["Devaraj K (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MAPREDUCE-2237?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13029132#comment-13029132 ] 

Devaraj K commented on MAPREDUCE-2237:
--------------------------------------

Hi Arun, 

{quote}Yes, the split was set to null to save memory. The fix should be trivial - add the split info to all LaunchTaskAction objects in the HeartbeatResponse object.{quote}


Adding the split info to LaunchTaskAction or keeping in MapTask without making it as null does not give any difference. I think it is not good to add split info in LaunchTaskAction which is specific to MapTask.

In 0.23 branch, problem is coming with splitMetaInfo. I think it is ok not to make splitMetaInfo as null because it contains only splitLocation and startOffset which are string and long fields. 

> Lost heartbeat response containing MapTask throws NPE when it is resent
> -----------------------------------------------------------------------
>
>                 Key: MAPREDUCE-2237
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-2237
>             Project: Hadoop Map/Reduce
>          Issue Type: Bug
>          Components: jobtracker
>    Affects Versions: 0.20.2, 0.21.0, 0.22.0
>            Reporter: Todd Lipcon
>
> When the JT sends a heartbeat response, it records it in trackerToHeartbeatResponseMap. But after MapTask writes its input split, it sets that split to null (assumedly to save memory?). So, if the heartbeat response is lost, and the JT needs to resend it, it will throw NPE since the split information has been lost.

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