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https://issues.apache.org/jira/browse/MAPREDUCE-7448?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18029741#comment-18029741
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ASF GitHub Bot commented on MAPREDUCE-7448:
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steveloughran commented on PR #6038:
URL: https://github.com/apache/hadoop/pull/6038#issuecomment-3401207827
cherrypicked to branch 3.4
FWIW people shouldn't be using v1 committer on cloud infra, and the manifest
committer also works perfectly well on HDFS, with higher performance from
parallel rename in job commit than v1.
> 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
> Assignee: 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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