jihoonson opened a new pull request #11138: URL: https://github.com/apache/druid/pull/11138
### Description https://github.com/apache/druid/pull/11058 added a new rule to handle empty tables, but Druid still uses `BindableConvention` for certain queries that read empty tables. The queries used in unit tests that are changed in this PR are such queries. The bug is in the `traitSet` of `DruidQueryRel` being set to a single trait of `Convention.NONE` when a `DruidQueryRel` is created from a `LogicalValues`. However, `LogicalValues` sometimes have extra traits set such as `RelCollation`. This makes `VolcanoPlanner` think the `DruidQueryRel` is not related to the `LogicalValues` even though `DruidQueryRel` is created from it. There is another method that changes `traitSet` when creating `DruidQueryRel` from `LogicalTableScan` which doesn't seem necessary as well. I will do some testing to make sure that it's not necessary and make another PR to fix it. <hr> This PR has: - [x] been self-reviewed. - [ ] using the [concurrency checklist](https://github.com/apache/druid/blob/master/dev/code-review/concurrency.md) (Remove this item if the PR doesn't have any relation to concurrency.) - [ ] added documentation for new or modified features or behaviors. - [ ] added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links. - [ ] added or updated version, license, or notice information in [licenses.yaml](https://github.com/apache/druid/blob/master/dev/license.md) - [x] added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader. - [x] added unit tests or modified existing tests to cover new code paths, ensuring the threshold for [code coverage](https://github.com/apache/druid/blob/master/dev/code-review/code-coverage.md) is met. - [ ] added integration tests. - [ ] been tested in a test Druid cluster. -- 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. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
