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  1. Hive
  2. HIVE-3562

Some limit can be pushed down to map stage

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Details

    • Bug
    • Status: Closed
    • Trivial
    • Resolution: Fixed
    • None
    • 0.12.0
    • None
    • None

    Description

      Queries with limit clause (with reasonable number), for example

      select * from src order by key limit 10;
      

      makes operator tree,
      TS-SEL-RS-EXT-LIMIT-FS

      But LIMIT can be partially calculated in RS, reducing size of shuffling.
      TS-SEL-RS(TOP-N)-EXT-LIMIT-FS

      Attachments

        1. HIVE-3562.D5967.1.patch
          19 kB
          Phabricator
        2. HIVE-3562.D5967.2.patch
          43 kB
          Phabricator
        3. HIVE-3562.D5967.3.patch
          66 kB
          Phabricator
        4. HIVE-3562.D5967.4.patch
          83 kB
          Phabricator
        5. HIVE-3562.D5967.5.patch
          91 kB
          Phabricator
        6. HIVE-3562.D5967.6.patch
          86 kB
          Phabricator
        7. HIVE-3562.D5967.7.patch
          103 kB
          Phabricator
        8. HIVE-3562.D5967.8.patch
          105 kB
          Phabricator
        9. HIVE-3562.D5967.9.patch
          104 kB
          Phabricator

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            Dates

              Created:
              Updated:
              Resolved:

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