mbutrovich opened a new pull request, #3703: URL: https://github.com/apache/datafusion-comet/pull/3703
## 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 #. ## Rationale for this change CometBroadcastExchangeExec previously broadcast an Array[ChunkedByteBuffer] with one entry per source partition. Each consumer partition independently deserialized all entries, creating a separate compression codec and Arrow IPC reader per entry. For broadcasts with many source partitions, this produced large per-task overhead in the hash join build-side collection. <img width="913" height="881" alt="Screenshot 2026-03-13 at 4 05 03 PM" src="https://github.com/user-attachments/assets/12ffb330-3c60-4f38-a778-b2bedc98c9f8"; /> <!-- 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? Decode and concatenate all broadcast batches into a single ChunkedByteBuffer on the driver using VectorSchemaRootAppender before broadcasting. Falls back to per-batch serialization if dictionary-encoded vectors are present. <!-- 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? <!-- 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)? --> 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
