Details

    • Type: Improvement Improvement
    • Status: Closed
    • Priority: Major Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 0.11.0
    • Component/s: Query Processor
    • Labels:
      None
    • Release Note:
      Map join hint will no longer be valid for some queries. Drop the hint in those cases. Hive will automatically try to convert join to map-join with config hive.auto.convert.join set to true.

      Description

      hive.auto.convert.join has been around for a long time, and is pretty stable.
      When mapjoin hint was created, the above parameter did not exist.

      The only reason for the user to specify a mapjoin currently is if they want
      it to be converted to a bucketed-mapjoin or a sort-merge bucketed mapjoin.
      Eventually, that should also go away, but that may take some time to stabilize.

      There are many rules in SemanticAnalyzer to handle the following trees:

      ReduceSink -> MapJoin
      Union -> MapJoin
      MapJoin -> MapJoin

      This should not be supported anymore. In any of the above scenarios, the
      user can get the mapjoin behavior by setting hive.auto.convert.join to true
      and not specifying the hint. This will simplify the code a lot.

      What does everyone think ?

      1. hive.3784.1.patch
        209 kB
        Namit Jain
      2. hive.3784.10.patch
        504 kB
        Namit Jain
      3. hive.3784.11.patch
        547 kB
        Namit Jain
      4. hive.3784.12.patch
        550 kB
        Namit Jain
      5. hive.3784.13.patch
        617 kB
        Namit Jain
      6. hive.3784.14.patch
        617 kB
        Namit Jain
      7. hive.3784.15.patch
        657 kB
        Namit Jain
      8. hive.3784.16.patch
        658 kB
        Namit Jain
      9. hive.3784.17.patch
        659 kB
        Namit Jain
      10. hive.3784.18.patch
        659 kB
        Namit Jain
      11. hive.3784.19.patch
        659 kB
        Namit Jain
      12. hive.3784.2.patch
        209 kB
        Namit Jain
      13. hive.3784.21.patch
        659 kB
        Namit Jain
      14. hive.3784.22.patch
        665 kB
        Namit Jain
      15. hive.3784.3.patch
        434 kB
        Namit Jain
      16. hive.3784.4.patch
        650 kB
        Namit Jain
      17. hive.3784.5.patch
        650 kB
        Namit Jain
      18. hive.3784.6.patch
        528 kB
        Namit Jain
      19. hive.3784.7.patch
        571 kB
        Namit Jain
      20. hive.3784.8.patch
        578 kB
        Namit Jain
      21. hive.3784.9.patch
        581 kB
        Namit Jain

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            • Assignee:
              Namit Jain
              Reporter:
              Namit Jain
            • Votes:
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              Watchers:
              13 Start watching this issue

              Dates

              • Created:
                Updated:
                Resolved:

                Development