[
https://issues.apache.org/jira/browse/MAPREDUCE-4842?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13537186#comment-13537186
]
Jason Lowe commented on MAPREDUCE-4842:
---------------------------------------
Patch race, sorry about that Asokan. Took a look at your most recent patch,
couple of comments:
* I see we're now clearing the lists when certain exceptions are caught, but
we're not holding a lock on the list when doing so?
* Per my previous comment, I think there is a race regarding inProgress where
we can do a merge with it set to false.
* Patch will need a unit test, feel free to grab the test from my previous
patch or roll your own if you have a cleaner one in mind.
> Shuffle race can hang reducer
> -----------------------------
>
> Key: MAPREDUCE-4842
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-4842
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: mrv2
> Affects Versions: 2.0.2-alpha, 0.23.5
> Reporter: Jason Lowe
> Assignee: Mariappan Asokan
> Priority: Blocker
> Attachments: MAPREDUCE-4842-2.patch, mapreduce-4842.patch,
> mapreduce-4842.patch, mapreduce-4842.patch, MAPREDUCE-4842.patch,
> MAPREDUCE-4842.patch, MAPREDUCE-4842.patch, MAPREDUCE-4842.patch
>
>
> Saw an instance where the shuffle caused multiple reducers in a job to hang.
> It looked similar to the problem described in MAPREDUCE-3721, where the
> fetchers were all being told to WAIT by the MergeManager but no merge was
> taking place.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
