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  1. Spark
  2. SPARK-6026

Eliminate the bypassMergeThreshold parameter and associated hash-ish shuffle within the Sort shuffle code

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Details

    • Bug
    • Status: Resolved
    • Major
    • Resolution: Incomplete
    • 1.3.0
    • None
    • Shuffle, Spark Core

    Description

      The bypassMergeThreshold parameter (and associated use of a hash-ish shuffle when the number of partitions is less than this) is basically a workaround for SparkSQL, because the fact that the sort-based shuffle stores non-serialized objects is a deal-breaker for SparkSQL, which re-uses objects. Once the sort-based shuffle is changed to store serialized objects, we should never be secretly doing hash-ish shuffle even when the user has specified to use sort-based shuffle (because of its otherwise worse performance).

      rxinadav, masters of shuffle, it would be helpful to get agreement from you on this proposal (and also a sanity check that I've correctly characterized the issue).

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              Unassigned Unassigned
              kayousterhout Kay Ousterhout
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                Updated:
                Resolved: