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https://issues.apache.org/jira/browse/MAPREDUCE-5817?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14697540#comment-14697540
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Hadoop QA commented on MAPREDUCE-5817:
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| (x) *{color:red}-1 overall{color}* |
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|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | pre-patch | 16m 2s | Pre-patch trunk compilation is
healthy. |
| {color:green}+1{color} | @author | 0m 0s | The patch does not contain any
@author tags. |
| {color:green}+1{color} | tests included | 0m 0s | The patch appears to
include 1 new or modified test files. |
| {color:green}+1{color} | javac | 7m 40s | There were no new javac warning
messages. |
| {color:green}+1{color} | javadoc | 9m 51s | There were no new javadoc
warning messages. |
| {color:green}+1{color} | release audit | 0m 23s | The applied patch does
not increase the total number of release audit warnings. |
| {color:red}-1{color} | checkstyle | 0m 33s | The applied patch generated 1
new checkstyle issues (total was 108, now 107). |
| {color:green}+1{color} | whitespace | 0m 0s | The patch has no lines that
end in whitespace. |
| {color:green}+1{color} | install | 1m 23s | mvn install still works. |
| {color:green}+1{color} | eclipse:eclipse | 0m 33s | The patch built with
eclipse:eclipse. |
| {color:green}+1{color} | findbugs | 1m 7s | The patch does not introduce
any new Findbugs (version 3.0.0) warnings. |
| {color:red}-1{color} | mapreduce tests | 8m 56s | Tests failed in
hadoop-mapreduce-client-app. |
| | | 46m 33s | |
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|| Reason || Tests ||
| Failed unit tests | hadoop.mapreduce.v2.app.TestJobEndNotifier |
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|| Subsystem || Report/Notes ||
| Patch URL |
http://issues.apache.org/jira/secure/attachment/12750568/MAPREDUCE-5817.002.patch
|
| Optional Tests | javadoc javac unit findbugs checkstyle |
| git revision | trunk / 84bf712 |
| checkstyle |
https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/5936/artifact/patchprocess/diffcheckstylehadoop-mapreduce-client-app.txt
|
| hadoop-mapreduce-client-app test log |
https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/5936/artifact/patchprocess/testrun_hadoop-mapreduce-client-app.txt
|
| Test Results |
https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/5936/testReport/ |
| Java | 1.7.0_55 |
| uname | Linux asf903.gq1.ygridcore.net 3.13.0-36-lowlatency #63-Ubuntu SMP
PREEMPT Wed Sep 3 21:56:12 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux |
| Console output |
https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/5936/console |
This message was automatically generated.
> mappers get rescheduled on node transition even after all reducers are
> completed
> --------------------------------------------------------------------------------
>
> Key: MAPREDUCE-5817
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-5817
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: applicationmaster
> Affects Versions: 2.3.0
> Reporter: Sangjin Lee
> Assignee: Sangjin Lee
> Attachments: MAPREDUCE-5817.001.patch, MAPREDUCE-5817.002.patch,
> mapreduce-5817.patch
>
>
> We're seeing a behavior where a job runs long after all reducers were already
> finished. We found that the job was rescheduling and running a number of
> mappers beyond the point of reducer completion. In one situation, the job ran
> for some 9 more hours after all reducers completed!
> This happens because whenever a node transition (to an unusable state) comes
> into the app master, it just reschedules all mappers that already ran on the
> node in all cases.
> Therefore, if any node transition has a potential to extend the job period.
> Once this window opens, another node transition can prolong it, and this can
> happen indefinitely in theory.
> If there is some instability in the pool (unhealthy, etc.) for a duration,
> then any big job is severely vulnerable to this problem.
> If all reducers have been completed, JobImpl.actOnUnusableNode() should not
> reschedule mapper tasks. If all reducers are completed, the mapper outputs
> are no longer needed, and there is no need to reschedule mapper tasks as they
> would not be consumed anyway.
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