neilconway opened a new issue, #22594: URL: https://github.com/apache/datafusion/issues/22594
### Is your feature request related to a problem or challenge? We can convert inner joins to semi joins automatically in some cases. For example, we can convert an inner join to a left semi join if * (1) Nothing above the join uses a column from the RHS of the join, and EITHER * (2) (A) The plan above the join is duplicate-insensitive (e.g., `DISTINCT` or some `GROUP BY`s), OR * (2) (B) We can use functional dependencies to prove that the RHS is unique on the join keys And symmetrically for inner -> right semi for LHS. Many of the TPC-DS queries would benefit from this. Plans in 2(A) generically benefit more because we're able to avoid producing duplicate tuples in the first place; 2(B) is a smaller win but still useful. ### Describe the solution you'd like _No response_ ### Describe alternatives you've considered _No response_ ### Additional context _No response_ -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
