alamb commented on issue #14115: URL: https://github.com/apache/datafusion/issues/14115#issuecomment-2602828070
> [@alamb](https://github.com/alamb) I found that [`NullBufferBuilder`](https://docs.rs/arrow-buffer/latest/arrow_buffer/builder/struct.NullBufferBuilder.html) doesn't have public methods for directly accessing the inner builder (only has `as_slice()` that returns the inner builder as a slice), so I can't modify the inner builder like trucate() `in take_n()`. Do you have any suggestions for how I might work around this limitation? 🙏 I think `take_n` is a pretty specialized function and should probably stay in DataFusion (unless someone wants to optimize it upstream in arrow) What I suggest is wrapping the NullBufferBuilder like this: ```rust pub(crate) struct MaybeNullBufferBuilder(NullBufferBulder); impl MaybeNullBufferBuilder { ... pub fn is_null(&self, row: usize) -> bool { // call inner NullBufferBuilder method self.0.get_bit(row) == 0 } ... } ``` In order to do this you will need to ensure NullBufferBuilder has all the required methods which will require an upstream PR to arrow-rs (for example to add `get_bit` and `capacity`) Does that make sense @Chen-Yuan-Lai ? -- 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
