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  1. Apache Drill
  2. DRILL-7141

Hash-Join (and Agg) should always spill to disk the least used partition

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    Details

    • Type: Improvement
    • Status: Open
    • Priority: Major
    • Resolution: Unresolved
    • Affects Version/s: 1.15.0
    • Fix Version/s: None
    • Component/s: Execution - Relational Operators
    • Labels:
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      Description

      When the probe-side data for a hash join is skewed, it is preferable to have the corresponding partition on the build side to be in memory. 

      Currently, with the spill-to-disk feature, the partition selected for spilling to disk is done at random. This means that a highly skewed probe-side data would also spill for lack of a corresponding hash table partition in memory. 

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          is related to

          Improvement - An improvement or enhancement to an existing feature or task. DRILL-6444 Hash Join: Avoid partitioning when memory is sufficient

          • Minor - Minor loss of function, or other problem where easy workaround is present.
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              • Assignee:
                ben-zvi Boaz Ben-Zvi
                Reporter:
                kkhatua Kunal Khatua
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                Dates

                • Created:
                  Updated: