linhr commented on issue #21955: URL: https://github.com/apache/datafusion/issues/21955#issuecomment-4386035053
Thanks @drin! My initial comment more came from the documentation perspective, since the monotonicity assumption is not obvious from the name `preimage`. So a developer may incorrectly implement `preimage` without knowing how it is actually used by the optimizer. Maybe we could define certain `monotonicity` method for scalar UDFs and consider this property in the optimizer. Using expression simplifier to invert monotonically decreasing functions makes sense for numeric functions, though I'm not sure if it works well for functions returning e.g. strings (whose monotonicity could also be well-defined). Glad to see the efforts in #18648! -- 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]
