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https://issues.apache.org/jira/browse/MAPREDUCE-1287?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Chris Douglas updated MAPREDUCE-1287:
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Description: Partitioners are currently called for each record, even
though all are destined for the same reduce. (was: HashPartitioner could be
optimized to not call the key's hashCode() if there is only 1 reducer.)
Release Note: For jobs with only one reducer, the Partitioner will no
longer be called. Applications depending on Partitioners modifying records for
single reducer jobs will need to move this functionality elsewhere.
Summary: Avoid calling Partitioner with only 1 reducer (was:
HashPartitioner calls hashCode() when there is only 1 reducer)
> Avoid calling Partitioner with only 1 reducer
> ---------------------------------------------
>
> Key: MAPREDUCE-1287
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-1287
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Affects Versions: 0.22.0
> Reporter: Ed Mazur
> Assignee: Ed Mazur
> Priority: Minor
> Fix For: 0.22.0
>
> Attachments: M1287-4.patch, M1287-5.patch, MAPREDUCE-1287.2.patch,
> MAPREDUCE-1287.3.patch, MAPREDUCE-1287.patch
>
>
> Partitioners are currently called for each record, even though all are
> destined for the same reduce.
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