alamb opened a new pull request, #6888: URL: https://github.com/apache/arrow-datafusion/pull/6888
Draft until I get performance numbers # 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 https://github.com/apache/arrow-datafusion/issues/6878 # Rationale for this change I noticed this while working on #4973 The `SUM` accumulator is general (it can handle sliding windows) but to be general it carries through an extra count for each group in the "state" -- this count is ignored. For low cardinality groups this likely isn't a problem but for large cardinality groups creating and carrying through the counts takes a measurable amount of time (I saw it in #6800) # What changes are included in this PR? Use a specialized sum accumulator for retractable windows and only track the counts there. For non # Are these changes tested? Existing coverage Performance: ``` TODO ``` <!-- 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? a little faster performance. I really expect this to help the code in #6800 so I can simplify the sum accumulator <!-- 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]
