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https://issues.apache.org/jira/browse/SPARK-2045?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14063006#comment-14063006
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Saisai Shao commented on SPARK-2045:
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Hi Matei, great to see your design doc, a simple question:
When will we do map-side combine in sort-based shuffle? At the beginning of
SortedFileWriter, or when merging the intermediate file like MR?
Looking forward to your plan, and hopes I can share my effort to this :).
> Sort-based shuffle implementation
> ---------------------------------
>
> Key: SPARK-2045
> URL: https://issues.apache.org/jira/browse/SPARK-2045
> Project: Spark
> Issue Type: New Feature
> Reporter: Matei Zaharia
> Attachments: Sort-basedshuffledesign.pdf
>
>
> Building on the pluggability in SPARK-2044, a sort-based shuffle
> implementation that takes advantage of an Ordering for keys (or just sorts by
> hashcode for keys that don't have it) would likely improve performance and
> memory usage in very large shuffles. Our current hash-based shuffle needs an
> open file for each reduce task, which can fill up a lot of memory for
> compression buffers and cause inefficient IO. This would avoid both of those
> issues.
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