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  1. IMPALA
  2. IMPALA-7955

Confusing, nonsensical predicates in DESCRIBE output

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Details

    • Bug
    • Status: Open
    • Minor
    • Resolution: Unresolved
    • Impala 3.1.0
    • None
    • Frontend
    • None
    • ghx-label-7

    Description

      Consider PlannerTest.testTpcds() with the TPCDS-Q47 query. Peruse the plan. Notice the following:

      33:HASH JOIN [INNER JOIN]
|  hash predicates: rank() + 1 = rank(), s_store_name = s_store_name, i_category = i_category, s_company_name = s_company_name, i_brand = i_brand

      What does rank() + 1 = rank() mean? Is it always false? What about s_store_name = s_store_name, is that always true?

      Probably this means tx.s_store_name = ty.s_store_name for some tables tx and ty. Expected the predicate to make that clear so I don't have to guess. Especially for that rank() + 1 = rank() expression, which table's rank() are we comparing to which other table's rank() + 1?

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            Unassigned Unassigned
            Paul.Rogers Paul Rogers
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              Created:
              Updated: