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Posted to github@arrow.apache.org by GitBox <gi...@apache.org> on 2022/01/24 20:47:58 UTC
[GitHub] [arrow-datafusion] alamb opened a new issue #1670: Query Optimizer: Add OUTER --> INNER join conversion
alamb opened a new issue #1670:
URL: https://github.com/apache/arrow-datafusion/issues/1670
**Is your feature request related to a problem or challenge? Please describe what you are trying to do.**
LEFT OUTER, RIGHT OUTER, and FULL OUTER JOINs are often more expensive to evaluate and preclude other optimizations (such as pushing down predicates as can be seen in #1618)
As such, sophisticated optimizers will actually rewrite OUTER joins to INNER joins depending on the predicates of the query to improve performance
**Describe the solution you'd like**
Add an OptimzierPass pass that will attempt to convert OUTER joins to inner joins.
This will require some non trivial research to figure out under what conditions the joins can be rewritten / converted
**Additional context**
Relevant discussion: https://github.com/apache/arrow-datafusion/pull/1618#discussion_r790020079
You can see a version of this code in Spark here: https://github.com/apache/spark/blob/aaf0e5e71509a2324e110e45366b753c7926c64b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/joins.scala#L119-L135
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[GitHub] [arrow-datafusion] alamb commented on issue #1670: Query Optimizer: Add OUTER --> INNER join conversion
Posted by GitBox <gi...@apache.org>.
alamb commented on issue #1670:
URL: https://github.com/apache/arrow-datafusion/issues/1670#issuecomment-1020534907
Whoops -- this is a dupe of https://github.com/apache/arrow-datafusion/issues/1585
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[GitHub] [arrow-datafusion] alamb commented on issue #1670: Query Optimizer: Add OUTER --> INNER join conversion
Posted by GitBox <gi...@apache.org>.
alamb commented on issue #1670:
URL: https://github.com/apache/arrow-datafusion/issues/1670#issuecomment-1020534907
Whoops -- this is a dupe of https://github.com/apache/arrow-datafusion/issues/1585
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[GitHub] [arrow-datafusion] alamb closed issue #1670: Query Optimizer: Add OUTER --> INNER join conversion
Posted by GitBox <gi...@apache.org>.
alamb closed issue #1670:
URL: https://github.com/apache/arrow-datafusion/issues/1670
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[GitHub] [arrow-datafusion] alamb closed issue #1670: Query Optimizer: Add OUTER --> INNER join conversion
Posted by GitBox <gi...@apache.org>.
alamb closed issue #1670:
URL: https://github.com/apache/arrow-datafusion/issues/1670
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