alamb commented on issue #13652: URL: https://github.com/apache/datafusion/issues/13652#issuecomment-2563115493
> For the [physical optimization](https://docs.rs/datafusion/43.0.0/datafusion/physical_optimizer/trait.PhysicalOptimizerRule.html) invariants, we have that the [output physical plan schema cannot change](https://datafusion.apache.org/contributor-guide/specification/invariants.html#physical-schema-is-invariant-under-physical-optimization); meaning the output results cannot change, but how we get the results can. > > What else should be included as a responsibility/check? Maintain input ordering if required? Here are some ideas based on bugs we have hit / my memory of what has changed and caused us pain: 1. Union inputs (can there be more than 2 inputs -- we use such plans in InfluxData but I am not sure what if anything else makes assumptions) 2. Union input schemas (I think initially they need to be 'coercable' and to be executable they need to be identical) 3. Projection_exec can't have zero exprs (is this an invariant?) -- 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
