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https://issues.apache.org/jira/browse/TEZ-3215?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15578833#comment-15578833
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Siddharth Seth commented on TEZ-3215:
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Couple of minor comments.
- Missing @override annotation on flush in MROutputs
- newRecordWriter / oldRecordWriter will be setup when MROutput.initialize is
called. Think this is avoidable.
- Could be called MultiMROutput - similar to MultiMRInput (which deals with
multiple readers). Up to you if you want to change this.
Any changes required to the associated OutputCommitter?
Otherwise, looks good to me.
> Support for MultipleOutputs
> ---------------------------
>
> Key: TEZ-3215
> URL: https://issues.apache.org/jira/browse/TEZ-3215
> Project: Apache Tez
> Issue Type: Improvement
> Reporter: Ming Ma
> Assignee: Ming Ma
> Attachments: TEZ-3215-2.patch, TEZ-3215-3.patch, TEZ-3215-4.patch,
> TEZ-3215-5.patch, TEZ-3215.patch
>
>
> Here is the use case. A reducer might write its output to more than one file.
> The file name will be based on the mapper key. We don't know all possible
> keys ahead of time. In MR, MultipleOutputs provides such support. I couldn't
> find anything readily available in Tez.
> * Set up one DataSink per file ahead of time won't work as we don't know all
> possible keys.
> * Use MR MultipleOutputs directly from the Tez application processor. It
> isn't clear how to pass TaskInputOutputContext to MultipleOutputs.
> * Tez MROutput can create a DataSink based on the specified outputFormat. But
> it can't take MR MultipleOutputs.
> I end up modifying Tez MROutput with HashMap {{recordWriters}} to achieve
> this. If this is a solved problem, can anyone explain how to do it?
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