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https://issues.apache.org/jira/browse/YARN-958?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14523389#comment-14523389
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Junping Du commented on YARN-958:
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Sounds like the problem is still valid. Shall we delay to cleanup
finishedApplications in RMNodeImpl until hear back from NM in next heartbeat?
However, that heartbeat could be lost also.
> NM may miss a heartbeat response from RM resulting into missed finished
> applications information.
> -------------------------------------------------------------------------------------------------
>
> Key: YARN-958
> URL: https://issues.apache.org/jira/browse/YARN-958
> Project: Hadoop YARN
> Issue Type: Bug
> Reporter: Omkar Vinit Joshi
>
> Today whenever RM receives heartbeat from NM it computes new heartbeat
> response and sends this response back to NM. Internally this response is sent
> to RMNodeImpl as an RMNodeEvent via dispatcher queue. Now if for some reason
> NM didn't get the older heartbeat then NM will try to heartbeat again..RM in
> turn will compute another response (if it has not already handled the event
> from queue) and will add this duplicate response on dispatcher queue. Today
> while computing response we remove completed applications from RMNodeImpl.
> Now if NM gets response without finished applications then it will never
> realize that those applications finished.
> Solution:-
> * We should synchronously update the newly computed response.
> * lastResponse should be moved out of RMNodeImpl and it should be stored in
> ResourceTrackerService itself just like ApplicationMasterService.
> * like YARN-744 we should introduce locking while computing response.
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