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https://issues.apache.org/jira/browse/MAPREDUCE-4961?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jerry Chen updated MAPREDUCE-4961:
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Status: Patch Available (was: Open)
The primary modifications are:
1. Go through ShuffleConsumerPlugin.runLocal when isLocal is set true. This
makes the code path for isLocal almost the same as !isLocal except the copy
phase was completed.
2. Default Shuffle implementation will route runLocal to
MergeManager.closeLocal for allow MergeManager implementation handling the
merge staff.
Please kindly help review.
> Map reduce running local should also go through ShuffleConsumerPlugin for
> enabling different MergeManager implementations
> -------------------------------------------------------------------------------------------------------------------------
>
> Key: MAPREDUCE-4961
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-4961
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Affects Versions: trunk
> Reporter: Jerry Chen
> Assignee: Jerry Chen
> Attachments: MAPREDUCE-4961.patch
>
> Original Estimate: 72h
> Remaining Estimate: 72h
>
> MAPREDUCE-4049 provide the ability for pluggable Shuffle and MAPREDUCE-4080
> extends Shuffle to be able to provide different MergeManager implementations.
> While using these pluggable features, I find that when a map reduce is
> running locally, a RawKeyValueIterator was returned directly from a static
> call of Merge.merge, which break the assumption that the Shuffle may provide
> different merge methods although there is no copy phase for this situation.
> The use case is when I am implementating a hash-based MergeManager, we don't
> need sort in map side, while when running the map reduce locally, the
> hash-based MergeManager will have no chance to be used as it goes directly to
> Merger.merge. This makes the pluggable Shuffle and MergeManager incomplete.
> So we need to move the code calling Merger.merge from Reduce Task to
> ShuffleConsumerPlugin implementation, so that the Suffle implementation can
> decide how to do the merge and return corresponding iterator.
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