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  1. Hive
  2. HIVE-6643

Add a check for cross products in plans and output a warning

    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 0.13.0
    • Component/s: None
    • Labels:
      None
    • Release Note:
      Added new config parameter 'hive.exec.check.crossproducts' to warn about Cross Products. By default this check is on.

      Description

      Now that we support old style join syntax, it is easy to write queries that generate a plan with a cross product.
      For e.g. say you have A join B join C join D on A.x = B.x and A.y = D.y and C.z = D.z
      So the JoinTree is:

      A — B
      |__ D — C

      Since we don't reorder join graphs, we will end up with a cross product between (A join B) and C

        Attachments

        1. HIVE-6643.1.patch
          124 kB
          Harish Butani
        2. HIVE-6643.2.patch
          125 kB
          Harish Butani
        3. HIVE-6643.3.patch
          125 kB
          Harish Butani
        4. HIVE-6643.4.patch
          135 kB
          Harish Butani
        5. HIVE-6643.5.patch
          161 kB
          Harish Butani
        6. HIVE-6643.6.patch
          167 kB
          Harish Butani
        7. HIVE-6643.7.patch
          167 kB
          Harish Butani

          Activity

            People

            • Assignee:
              rhbutani Harish Butani
              Reporter:
              rhbutani Harish Butani
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              Dates

              • Created:
                Updated:
                Resolved: