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https://issues.apache.org/jira/browse/MAPREDUCE-5043?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13591550#comment-13591550
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Hadoop QA commented on MAPREDUCE-5043:
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{color:green}+1 overall{color}. Here are the results of testing the latest
attachment
http://issues.apache.org/jira/secure/attachment/12571761/MAPREDUCE-5043.patch
against trunk revision .
{color:green}+1 @author{color}. The patch does not contain any @author
tags.
{color:green}+1 tests included{color}. The patch appears to include 2 new
or modified test files.
{color:green}+1 tests included appear to have a timeout.{color}
{color:green}+1 javac{color}. The applied patch does not increase the
total number of javac compiler warnings.
{color:green}+1 javadoc{color}. The javadoc tool did not generate any
warning messages.
{color:green}+1 eclipse:eclipse{color}. The patch built with
eclipse:eclipse.
{color:green}+1 findbugs{color}. The patch does not introduce any new
Findbugs (version 1.3.9) warnings.
{color:green}+1 release audit{color}. The applied patch does not increase
the total number of release audit warnings.
{color:green}+1 core tests{color}. The patch passed unit tests in
hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app
hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs.
{color:green}+1 contrib tests{color}. The patch passed contrib unit tests.
Test results:
https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/3377//testReport/
Console output:
https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/3377//console
This message is automatically generated.
> Fetch failure processing can cause AM event queue to backup and eventually OOM
> ------------------------------------------------------------------------------
>
> Key: MAPREDUCE-5043
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-5043
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: mr-am
> Affects Versions: 0.23.7, 2.0.4-beta
> Reporter: Jason Lowe
> Assignee: Jason Lowe
> Priority: Blocker
> Attachments: MAPREDUCE-5043.patch
>
>
> Saw an MRAppMaster with a 3G heap OOM. Upon investigating another instance
> of it running, we saw the UI in a weird state where the task table and task
> attempt tables in the job overview page weren't consistent. The AM log
> showed the AsyncDispatcher had hundreds of thousands of events in the event
> queue, and jstacks showed it spending a lot of time in fetch failure
> processing. It turns out fetch failure processing is currently *very*
> expensive, with a triple {{for}} loop where the inner loop is calling the
> quite-expensive {{TaskAttempt.getReport}}. That function ends up
> type-converting the entire task report, counters and all, and performing
> locale conversions among other things. It does this for every reduce task in
> the job, for every map task that failed. And when it's done building up the
> large task report, it pulls out one field, the phase, then throws the report
> away.
> While the AM is busy processing fetch failures, tasks attempts are continuing
> to send events to the AM including memory-expensive events like status
> updates which include the counters. These back up in the AsyncDispatcher
> event queue and eventually even an AM with a large heap size will run out of
> memory and crash or expire because it thrashes in garbage collect.
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