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https://issues.apache.org/jira/browse/MAPREDUCE-5861?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13999017#comment-13999017
]
Hudson commented on MAPREDUCE-5861:
-----------------------------------
SUCCESS: Integrated in Hadoop-trunk-Commit #5605 (See
[https://builds.apache.org/job/Hadoop-trunk-Commit/5605/])
MAPREDUCE-5861. finishedSubMaps field in LocalContainerLauncher does not need
to be volatile. (Contributed by Tsuyoshi OZAWA) (junping_du:
http://svn.apache.org/viewcvs.cgi/?root=Apache-SVN&view=rev&rev=1594795)
* /hadoop/common/trunk/hadoop-mapreduce-project/CHANGES.txt
*
/hadoop/common/trunk/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapred/LocalContainerLauncher.java
> finishedSubMaps field in LocalContainerLauncher does not need to be volatile
> ----------------------------------------------------------------------------
>
> Key: MAPREDUCE-5861
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-5861
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Reporter: Ted Yu
> Assignee: Tsuyoshi OZAWA
> Priority: Minor
> Fix For: 2.5.0
>
> Attachments: MAPREDUCE-5861.1.patch, MAPREDUCE-5861.2.patch
>
>
> Around line 374:
> {code}
> if (++finishedSubMaps == numMapTasks) {
> doneWithMaps = true;
> }
> {code}
> The increment of finishedSubMaps is not atomic.
> See the answer to
> http://stackoverflow.com/questions/9749746/what-is-the-difference-of-atomic-volatile-synchronize
> .
> AtomicInteger can be used to achieve atomicity.
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