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https://issues.apache.org/jira/browse/MAPREDUCE-7448?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Steve Loughran resolved MAPREDUCE-7448.
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Fix Version/s: 3.5.0
3.4.3
Resolution: Fixed
> Skipping cleanup with FileOutputCommitter V1 can corrupt output: warn and
> document
> ----------------------------------------------------------------------------------
>
> Key: MAPREDUCE-7448
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-7448
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Reporter: ConfX
> Priority: Critical
> Labels: pull-request-available
> Fix For: 3.5.0, 3.4.3
>
> Attachments: reproduce.sh
>
>
> h2. What happened
> I turned on {{mapreduce.fileoutputcommitter.cleanup.skipped=true}} and then
> the version 1 of {{FileOutputCommitter}} can commit several times, which is
> unexpected.
> h2. Where's the problem
> In {{{}FileOutputCommitter.commitJobInternal{}}},
> {noformat}
> if (algorithmVersion == 1) {
> for (FileStatus stat: getAllCommittedTaskPaths(context)) {
> mergePaths(fs, stat, finalOutput, context);
> }
> } if (skipCleanup) {
> LOG.info("Skip cleanup the _temporary folders under job's output " +
> "directory in commitJob.");
> ...{noformat}
> Here if we skip cleanup, the _temporary folder would not be deleted and the
> _SUCCESS file would also not be created, which cause the {{mergePaths}} next
> time to not fail.
> h2. How to reproduce
> # set {{{}mapreduce.fileoutputcommitter.cleanup.skipped{}}}={{{}true{}}}
> # run
> {{org.apache.hadoop.mapred.TestFileOutputCommitter#testCommitterWithDuplicatedCommitV1}}
> you should observe
> {noformat}
> java.lang.AssertionError: Duplicate commit successful: wrong behavior for
> version 1.
> at org.junit.Assert.fail(Assert.java:89)
> at
> org.apache.hadoop.mapred.TestFileOutputCommitter.testCommitterWithDuplicatedCommitInternal(TestFileOutputCommitter.java:295)
> at
> org.apache.hadoop.mapred.TestFileOutputCommitter.testCommitterWithDuplicatedCommitV1(TestFileOutputCommitter.java:269){noformat}
> For an easy reproduction, run the reproduce.sh in the attachment.
> We are happy to provide a patch if this issue is confirmed.
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