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Posted to mapreduce-issues@hadoop.apache.org by "jiayuhan-it (JIRA)" <ji...@apache.org> on 2017/12/07 10:37:00 UTC
[jira] [Comment Edited] (MAPREDUCE-7017) Too many times of
meaningless invocation in TaskAttemptImpl#resolveHosts
[ https://issues.apache.org/jira/browse/MAPREDUCE-7017?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16281660#comment-16281660 ]
jiayuhan-it edited comment on MAPREDUCE-7017 at 12/7/17 10:36 AM:
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cc @Arun Suresh and Konstantinos Karanasos
Please help to review.
was (Author: magicbunny):
cc Arun Suresh and Konstantinos Karanasos
Please help to review.
> Too many times of meaningless invocation in TaskAttemptImpl#resolveHosts
> ------------------------------------------------------------------------
>
> Key: MAPREDUCE-7017
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-7017
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Components: mr-am
> Affects Versions: 3.0.0-alpha4
> Reporter: jiayuhan-it
> Attachments: MAPREDUCE-7017.001.patch
>
>
> MRAppMaster uses {{TaskAttemptImpl::resolveHosts}} to determine the dataLocalHosts for each task when the location of data split is IP, which will call a lot of times ( taskNum * dfsReplication) of function {{InetAddress::getByName}} and most of the funcition calls are redundant. When the job has a great number of tasks and the speed of DNS resolution is not fast enough, it will take a lot of time at this stage before the job running.
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