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  1. Hive
  2. HIVE-5369 Annotate hive operator tree with statistics from metastore
  3. HIVE-5921

Better heuristics for worst case statistics estimates for join, limit and filter operator

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Details

    • Sub-task
    • Status: Resolved
    • Major
    • Resolution: Fixed
    • 0.13.0
    • 0.13.0
    • Query Processor, Statistics
    • None

    Description

      This is a subtask of HIVE-5369. In worst case (i.e; absence of column statistics) HIVE-5849 improved the basic statistics with heuristics. But the heuristics failed to provide better estimates in few cases. For example: FILTER operator heuristics did not take into account the number of predicates and if the predicate contains partition column. Also, JOIN estimates were too aggressive and was not user configurable.

      Attachments

        1. HIVE-5921.1.patch
          532 kB
          Prasanth Jayachandran
        2. HIVE-5921.2.patch
          532 kB
          Prasanth Jayachandran
        3. HIVE-5921.3.patch
          545 kB
          Prasanth Jayachandran
        4. HIVE-5921.4.patch
          544 kB
          Prasanth Jayachandran

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            prasanth_j Prasanth Jayachandran Assign to me
            prasanth_j Prasanth Jayachandran
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              Updated:
              Resolved:

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