Dandandan opened a new pull request, #20780: URL: https://github.com/apache/datafusion/pull/20780
When a ProjectionExec duplicates columns from the same input (e.g., count(Int64(1))@1 as count(*) and count(Int64(1))@1 as count(Int64(1))), the outer ProjectionExec that later drops these duplicates could not be pushed through Sort/SortPreservingMerge operators because update_ordering failed to match columns with different names but the same underlying data. This fix enhances try_swapping_with_projection for both SortExec and SortPreservingMergeExec to use equivalence properties as a fallback when the direct column name+index match fails. By normalizing sort expressions through equivalence classes, the projection can now be pushed through sort operators, eliminating both the redundant inner ProjectionExec (which duplicated columns) and the outer ProjectionExec (which dropped them). This removes 2 unnecessary ProjectionExec nodes per affected query in ClickBench (Q7, Q15, Q16, Q18), reducing plan complexity and avoiding redundant column copies at execution time. https://claude.ai/code/session_0142EfkmyEyEH7f36FyMKzhQ ## Which issue does this PR close? <!-- We generally require a GitHub issue to be filed for all bug fixes and enhancements and this helps us generate change logs for our releases. You can link an issue to this PR using the GitHub syntax. For example `Closes #123` indicates that this PR will close issue #123. --> - Closes #. ## Rationale for this change <!-- Why are you proposing this change? If this is already explained clearly in the issue then this section is not needed. Explaining clearly why changes are proposed helps reviewers understand your changes and offer better suggestions for fixes. --> ## What changes are included in this PR? <!-- There is no need to duplicate the description in the issue here but it is sometimes worth providing a summary of the individual changes in this PR. --> ## Are these changes tested? <!-- We typically require tests for all PRs in order to: 1. Prevent the code from being accidentally broken by subsequent changes 2. Serve as another way to document the expected behavior of the code If tests are not included in your PR, please explain why (for example, are they covered by existing tests)? --> ## Are there any user-facing changes? <!-- If there are user-facing changes then we may require documentation to be updated before approving the PR. --> <!-- If there are any breaking changes to public APIs, please add the `api change` label. --> -- 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]
