rubenada opened a new pull request #2131:
URL: https://github.com/apache/calcite/pull/2131


   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.
   
   The goal of this patch is fixing the ANTI computation and providing a more 
accurate value for LEFT / RIGHT / FULL.
   


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