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  1. Hive
  2. HIVE-22238

PK/FK selectivity estimation underscales estimations

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      at this point the parent operators rownum is scaled according to pkfkselectivity

      however pkfkselectivity is computed on a whole subtree.

      Scaling it by that amount will count in estimation already used when parentstats was calculated...so depending on the number of upstream joins - this may lead to severe underestimations

      what happened was:

      • optimization was able to push the filter to the other side of the join
      • as a result the incoming data was already filtered
      • scaling down by the PK selectiviy - was actually already there...but a new "scaling" happened

        Attachments

        1. HIVE-22238.10.patch
          1.54 MB
          Zoltan Haindrich
        2. HIVE-22238.10.patch
          1.54 MB
          Zoltan Haindrich
        3. HIVE-22238.10.patch
          1.54 MB
          Zoltan Haindrich
        4. HIVE-22238.10.patch
          1.54 MB
          Zoltan Haindrich
        5. HIVE-22238.09.patch
          1.54 MB
          Zoltan Haindrich
        6. HIVE-22238.07.patch
          1.48 MB
          Zoltan Haindrich
        7. HIVE-22238.06.patch
          1.48 MB
          Zoltan Haindrich
        8. HIVE-22238.06.patch
          1.48 MB
          Zoltan Haindrich
        9. HIVE-22238.05.patch
          1.48 MB
          Zoltan Haindrich
        10. HIVE-22238.05.patch
          1.48 MB
          Zoltan Haindrich
        11. HIVE-22238.05.patch
          1.48 MB
          Zoltan Haindrich
        12. HIVE-22238.05.patch
          1.48 MB
          Zoltan Haindrich
        13. HIVE-22238.05.patch
          1.48 MB
          Zoltan Haindrich
        14. HIVE-22238.04.patch
          1.42 MB
          Zoltan Haindrich
        15. HIVE-22238.03.patch
          1.42 MB
          Zoltan Haindrich
        16. HIVE-22238.02.patch
          2 kB
          Zoltan Haindrich
        17. HIVE-22238.01.patch
          1.0 kB
          Zoltan Haindrich

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              • Assignee:
                kgyrtkirk Zoltan Haindrich
                Reporter:
                kgyrtkirk Zoltan Haindrich
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                  Updated:
                  Resolved:

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