blaginin opened a new pull request, #14684: URL: https://github.com/apache/datafusion/pull/14684
## Which issue does this PR close? Related to https://github.com/apache/datafusion/issues/14563 ## Rationale for this change Currently, when `with_column_renamed` is called, a new Projection layer is always created. For example, in the `dataframe` benchmark, logical plan looks like this:  These layers do not affect the query itself (as they are removed by `optimize_projections`), but they make renaming new columns (and optimization itself) quite slow. ## What changes are included in this PR? I added an optimization for one edge case - when there's already a projection on top and we're adding a new one. This is a common scenario, especially when renaming many columns (as in the `dataframe` benchmark). Instead of adding a new projection layer on top, we replace the existing one if possible. ## Are these changes tested? Extended test case ## Are there any user-facing changes? No -- 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: github-unsubscr...@datafusion.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org
