a2l007 opened a new pull request #10030: URL: https://github.com/apache/druid/pull/10030
<!-- Thanks for trying to help us make Apache Druid be the best it can be! Please fill out as much of the following information as is possible (where relevant, and remove it when irrelevant) to help make the intention and scope of this PR clear in order to ease review. --> Fixes #9791 . <!-- Replace XXXX with the id of the issue fixed in this PR. Remove this section if there is no corresponding issue. Don't reference the issue in the title of this pull-request. --> <!-- If you are a committer, follow the PR action item checklist for committers: https://github.com/apache/druid/blob/master/dev/committer-instructions.md#pr-and-issue-action-item-checklist-for-committers. --> ### Description Introduces a new interface `MultiTableDataSource` that extends `DataSource` and provides extensibilty for multi table datasources. Presently, [UnionDataSource](https://druid.apache.org/docs/latest/querying/datasource.html#union) is the only datasource within druid under this category. For more details on the usecase, please refer to the proposal. `UnionDataSource` has been refactored to be an implementation of `MultiTableDataSource`. As a result, union datasource queries no longer execute sequentially per datasource and this improves the query performance. <hr> This PR has: - [x] been self-reviewed. - [x] added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links. - [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. - [x] been tested in a test Druid cluster. <!-- Check the items by putting "x" in the brackets for the done things. Not all of these items apply to every PR. Remove the items which are not done or not relevant to the PR. None of the items from the checklist above are strictly necessary, but it would be very helpful if you at least self-review the PR. --> <hr> ### Key classes changed in this PR 1. `CachingClusteredClient` 2. `ServerManager` 3. `UnionDataSource` ---------------------------------------------------------------- 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]
