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  1. Hive
  2. HIVE-21537

Scalar query rewrite could be improved to not generate an extra join if subquery is guaranteed to produce atmost one row

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    Details

    • Type: Improvement
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 4.0.0
    • Fix Version/s: 4.0.0
    • Component/s: Query Planning
    • Labels:

      Description

      Currently Hive planner introduces this branch and later executes a rule to remove this branch if it could.
      Subquery remove rule itself could check if subquery will produce max one row (using relmetadat's getMaxRowCount) and avoid introducing this branch.

        Attachments

        1. HIVE-21537.1.patch
          49 kB
          Vineet Garg
        2. HIVE-21537.2.patch
          287 kB
          Vineet Garg
        3. HIVE-21537.3.patch
          294 kB
          Vineet Garg
        4. HIVE-21537.4.patch
          295 kB
          Vineet Garg
        5. HIVE-21537.5.patch
          295 kB
          Vineet Garg

          Activity

            People

            • Assignee:
              vgarg Vineet Garg
              Reporter:
              vgarg Vineet Garg
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              Dates

              • Created:
                Updated:
                Resolved: