jhorstmann opened a new pull request #1499: URL: https://github.com/apache/arrow-rs/pull/1499
# 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 #510. # Rationale for this change This is an alternative implementation to #521 of the `nullif` kernel that works by slicing the buffers of the array depending on the data type. For most data types this can be done without copying data. The exceptions are boolean arrays (when the offset is not a multiple of 8) and list arrays because there are some assumptions that offsets start at zero. There are several TODO still left in the code to verify the correct slicing logic for some data types. It also seems a bit strange that this slicing logic is only needed for a single kernel and I also don't like that we still need to copy for some data types. A better design would require some larger refactorings of the current data model: - Remove the `offset` from `ArrayData` so that all slicing has to be pushed down into buffers - Add a `offset` field to `Bitmap` so that bitmaps can be sliced without copying - Also use the `Bitmap` as the data holder for boolean arrays # What changes are included in this PR? I added the kernel as a separate function to make the diff easier to read, if we decide to merge this it should replace the existing `nullif` kernel. The api changes since the `nullif` kernel now takes an `ArrayRef` instead of a `PrimitiveArray`. -- 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]
