[jira] [Commented] (MAPREDUCE-6009) Map-only job with new-api runs wrong OutputCommitter when cleanup scheduled in a reduce slot

["Zheng Shao (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MAPREDUCE-6009?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14638392#comment-14638392 ] 

Zheng Shao commented on MAPREDUCE-6009:
---------------------------------------

We just hit this bug in an unpatched version of MR1.

The situation is that HCatalog submits a Map-only job and hopes to use OutputCommitter.commitJob to create a Hive partition.  Because of this bug, the Hive partition was never created.

Our sanity check on the hive table + workflow retry mechanism allowed us to have this bug running in production for a long time (and wasting compute resources).  It's great that this is fixed.


> Map-only job with new-api runs wrong OutputCommitter when cleanup scheduled in a reduce slot
> --------------------------------------------------------------------------------------------
>
>                 Key: MAPREDUCE-6009
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-6009
>             Project: Hadoop Map/Reduce
>          Issue Type: Bug
>          Components: client, job submission
>    Affects Versions: 1.2.1
>            Reporter: Gera Shegalov
>            Assignee: Gera Shegalov
>            Priority: Blocker
>             Fix For: 1.3.0, 1.2.2
>
>         Attachments: MAPREDUCE-6009.v01-branch-1.2.patch, MAPREDUCE-6009.v02-branch-1.2.patch
>
>
> In branch 1 job commit is executed in a JOB_CLEANUP task that may run in either map or reduce slot
> in org.apache.hadoop.mapreduce.Job#setUseNewAPI there is a logic setting new-api flag only for reduce-ful jobs.
> {code}
>     if (numReduces != 0) {
>       conf.setBooleanIfUnset("mapred.reducer.new-api",
>                              conf.get(oldReduceClass) == null);
>       ...
> {code}
> Therefore, when cleanup runs in a reduce slot, ReduceTask inits using the old API and runs incorrect default OutputCommitter, instead of consulting OutputFormat.



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