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https://issues.apache.org/jira/browse/MAPREDUCE-2541?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13084832#comment-13084832
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Hudson commented on MAPREDUCE-2541:
-----------------------------------
Integrated in Hadoop-Mapreduce-trunk #754 (See
[https://builds.apache.org/job/Hadoop-Mapreduce-trunk/754/])
MAPREDUCE-2541. Fixed a race condition in IndexCache.removeMap. Contributed
by Binglin Chang.
acmurthy :
http://svn.apache.org/viewcvs.cgi/?root=Apache-SVN&view=rev&rev=1157346
Files :
*
/hadoop/common/trunk/mapreduce/src/test/mapred/org/apache/hadoop/mapred/TestIndexCache.java
* /hadoop/common/trunk/mapreduce/CHANGES.txt
*
/hadoop/common/trunk/mapreduce/src/java/org/apache/hadoop/mapred/IndexCache.java
> Race Condition in IndexCache(readIndexFileToCache,removeMap) causes value of
> totalMemoryUsed corrupt, which may cause TaskTracker continue throw Exception
> ----------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: MAPREDUCE-2541
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-2541
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: tasktracker
> Affects Versions: 0.20.1, 0.21.0, 0.22.0, 0.23.0
> Environment: all
> Reporter: Binglin Chang
> Assignee: Binglin Chang
> Priority: Critical
> Fix For: 0.23.0
>
> Attachments: MAPREDUCE-2541.patch, MAPREDUCE-2541.v2.patch
>
>
> The race condition goes like this:
> Thread1: readIndexFileToCache() totalMemoryUsed.addAndGet(newInd.getSize())
> Thread2: removeMap() totalMemoryUsed.addAndGet(-info.getSize());
> When SpillRecord is being read from fileSystem, client kills the job,
> info.getSize() equals 0, so in fact totalMemoryUsed is not reduced, but after
> thread1 finished reading SpillRecord, it adds the real index size to
> totalMemoryUsed, which makes the value of totalMemoryUsed wrong(larger).
> When this value(totalMemoryUsed) exceeds totalMemoryAllowed (this usually
> happens when a vary large job with vary large reduce number is killed by the
> user, probably because the user sets a wrong reduce number by mistake), and
> actually indexCache has not cache anything, freeIndexInformation() will throw
> exception constantly.
> A quick fix for this issue is to make removeMap() do nothing, let
> freeIndexInformation() do this job only.
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