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  1. Spark
  2. SPARK-32573

Anti Join Improvement with EmptyHashedRelation and EmptyHashedRelationWithAllNullKeys

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    Details

    • Type: Improvement
    • Status: Resolved
    • Priority: Minor
    • Resolution: Fixed
    • Affects Version/s: 3.0.0
    • Fix Version/s: 3.1.0
    • Component/s: SQL
    • Labels:
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      Description

      InĀ SPARK-32290, we introduced several new types of HashedRelation

      • EmptyHashedRelation
      • EmptyHashedRelationWithAllNullKeys

      They were all limited to used only in NAAJ scenario. These new HashedRelation could be applied to other scenario for performance improvements.

      • EmptyHashedRelation could also be used in Normal AntiJoin for fast stop
      • While AQE is on and buildSide is EmptyHashedRelationWithAllNullKeys, can convert NAAJ to a Empty LocalRelation to skip meaningless data iteration since in Single-Key NAAJ, if null key exists in BuildSide, will drop all records in streamedSide.

      This Patch including two changes.

      • using EmptyHashedRelation to do fast stop for common anti join as well
      • In AQE, eliminate BroadcastHashJoin(NAAJ) if buildSide is a EmptyHashedRelationWithAllNullKeys

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            • Assignee:
              leanken Leanken.Lin
              Reporter:
              leanken Leanken.Lin
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              • Created:
                Updated:
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