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  1. Apache Drill
  2. DRILL-3130

Project can be pushed below union all / union to improve performance

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    Description

      A query such as 

      Select a from 
(select a, b, c, ..., union all select a, b, c, ...)

      will perform Union-All over all the specified columns on the two sides, despite the fact that only one column is asked for at the end. Ideally, we should perform ProjectPushDown rule for Union & Union-All to avoid them to generate results which will be discarded at the end.

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          is blocked by

          Improvement - An improvement or enhancement to an existing feature or task. DRILL-3855 Enable FilterSetOpTransposeRule, DrillProjectSetOpTransposeRule

          • Major - Major loss of function.
          • Closed
          is related to

          Bug - A problem which impairs or prevents the functions of the product. DRILL-6417 Project is not pushed into scan if use subquery with UNION operator

          • Major - Major loss of function.
          • Closed

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              vitalii Vitalii Diravka
              seanhychu Sean Hsuan-Yi Chu
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                Updated:
                Resolved: