eejbyfeldt opened a new pull request, #542: URL: https://github.com/apache/datafusion-comet/pull/542
## 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 #481. ## Rationale for this change When spark reads and writes timestamps in parquet file it using the following code: https://github.com/apache/spark/blob/v3.5.1/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/DateTimeUtils.scala#L48-L66 to convert from the Long microsecond timestamp into the julian date + nano second format used in parquet. Because of the logic is implement dates like `"290000-12-31T01:00:00+02:00"` will lead to overflow both when encoding and deconding the value. Since it for both the reading and writing it "cancels out" and still gives the expected results. But unintuitivly this means the date in year 290000 is stored with a negative day offset. <!-- 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? This changes the comet code to use wrapping_mul/add to make it explicit that wrapping overflow is expected and desired. <!-- 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. --> ## How are these changes tested? Existing and new unit test in CometCastSuite. <!-- 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)? --> -- 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
