mustafasrepo opened a new pull request, #8960: URL: https://github.com/apache/arrow-datafusion/pull/8960
## 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 [#8942](https://github.com/apache/arrow-datafusion/issues/8942). ## Rationale for this change See issue. <!-- 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? Currently projections are not inserted to logical plan, if its input schema and its schema are same. However, this equality is not a sufficient condition. See #8942 for an example how can be a problem. On top of that condition, we need to make sure that projection is trivial (e.g it just emits its input). Then we can deem Projection unnecessary. However, adding `.iter().all(is_trivial)` check inserts additional `ProjectionExec`s to the plan for 2 test cases as observed by @gruuya. Even if these test plans retract, I think we should do this change. Because removing `Projection` in those plan overfits the name being same after casting (this assumption is not safe). I think, what we should really do for those queries is rewriting window expression so that they no longer contain CAST expr after once their input have casted result. I think that is the concern of another PR. @gruuya suggested [PR](https://github.com/apache/arrow-datafusion/pull/8951) for fixing this issue without retracting these window tests. However, I think that PR solves the problem only for consecutive projections. Note: This PR is an implementation of @gruuya's suggestion, with his test in the [PR](https://github.com/apache/arrow-datafusion/pull/8951). <!-- 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? Yes <!-- 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]
