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Posted to dev@calcite.apache.org by "Ruben Q L (Jira)" <ji...@apache.org> on 2020/09/01 15:30:01 UTC

[jira] [Created] (CALCITE-4208) Improve metadata row count for Join

Ruben Q L created CALCITE-4208:
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             Summary: Improve metadata row count for Join
                 Key: CALCITE-4208
                 URL: https://issues.apache.org/jira/browse/CALCITE-4208
             Project: Calcite
          Issue Type: Improvement
          Components: core
            Reporter: Ruben Q L


Currently, the default metadata row count for join {{RelMdRowCount#getRowCount(Join rel, RelMetadataQuery mq)}} relies on {{RelMdUtil.getJoinRowCount}}. This method has several issues:
 - In case of ANTI join, it returns the same estimation as a SEMI join
 - In other cases (INNER, LEFT, RIGHT, FULL), it returns always the same formula:
 {{leftRowCount * rightRowCount * mq.getSelectivity(join, condition)}}
 which seems valid for an INNER join, but not for LEFT / RIGHT / FULL.



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