HippoBaro opened a new pull request, #11264: URL: https://github.com/apache/arrow-rs/pull/11264
# 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. --> - Closes #11263. # 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. --> Caller-supplied distinct counts describe an individual write, while column metadata describes the entire column chunk. Once earlier data makes the column-wide count unknown, a later write cannot safely restore that count using only its own batch statistics. # 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. --> - Use column and page metrics to detect prior data instead of the page-local encoder value count. - Accept a caller-supplied distinct count only when there is no prior data in the column chunk. - Update the regression test to force a page boundary and verify that the column-wide distinct count remains absent while page statistics remain correct. # 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)? If this PR claims a performance improvement, please include evidence such as benchmark results. --> Yes. The updated regression covers distinct-count invalidation across a page flush and checks that page-level statistics are preserved. # 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 call them out. --> There are no public API changes. -- 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]
