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https://issues.apache.org/jira/browse/HADOOP-3308?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Chris Douglas updated HADOOP-3308:
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Attachment: 3308-2.patch
Made the class final per Nicholas's recommendation. Instead of instance vars,
it should be sufficient to make them final in the call to sort. Also added an
additional test case to test the new code more thoroughly.
> Improve QuickSort by excluding values eq the pivot from the partition
> ---------------------------------------------------------------------
>
> Key: HADOOP-3308
> URL: https://issues.apache.org/jira/browse/HADOOP-3308
> Project: Hadoop Core
> Issue Type: Improvement
> Reporter: Chris Douglas
> Assignee: Chris Douglas
> Fix For: 0.18.0
>
> Attachments: 3308-0.patch, 3308-1.patch, 3308-2.patch
>
>
> The current implementation of QuickSort naively partitions on either side of
> the pivot. We can improve this by partitioning on either side of the set of
> values equal to the pivot. This assumes that comparing keys is expensive
> compared to swaps and index comparisons (which it certainly is in MapTask,
> and should be in general).
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