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  1. Kudu
  2. KUDU-2380

Selective predicates when selecting high number of columns burns CPU in SerializeRowBlock

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Details

    • Improvement
    • Status: Resolved
    • Major
    • Resolution: Fixed
    • None
    • 1.8.0
    • perf, tserver
    • None

    Description

      Testing a table with 280 columns, I found the following performance characteristic:

      • scanning all 280 columns with a selective non-key predicate which matches 0 rows took 8.28s
      • scanning no columns (count query) with the same predicate which matches 0 rows took 314ms.

      This suggests that we are burning 96% of our CPU doing useless work for this query.

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            tlipcon Todd Lipcon
            tlipcon Todd Lipcon
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