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  1. IMPALA
  2. IMPALA-5648

Count star optimisation regressed Parquet memory estimate accuracy

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      The Parquet memory estimate is based on the number of columns scanned in the file. Before IMPALA-5036, count queries correctly counted zero columns read because it was a metadata-only scan. The count-star optimisation is also a metadata-only scan but the memory estimate is based on the column actually being scanned.

      This regression is apparent in the planner test changes:
      https://gerrit.cloudera.org/#/c/6812/12/testdata/workloads/functional-planner/queries/PlannerTest/resource-requirements.test

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              • Assignee:
                tarmstrong Tim Armstrong
                Reporter:
                tarmstrong Tim Armstrong
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