clintropolis opened a new pull request #10053: URL: https://github.com/apache/druid/pull/10053
### Description This PR fixes an issue with TopN algorithm selection to make sure that string columns with dictionaries also have sorted and unique dictionaries. The off-heap pooled algorithm assumes this to be true, so we must use the heap based algorithm in cases where the column has a dictionary, but it is not unique or sorted. Prior to this PR, the added test produces the following incorrect results prior to this PR: ``` 2020-06-18T18:52:21,520 INFO [main] org.apache.druid.sql.calcite.BaseCalciteQueryTest - row #0: [a, 3] 2020-06-18T18:52:21,520 INFO [main] org.apache.druid.sql.calcite.BaseCalciteQueryTest - row #1: [a, 3] 2020-06-18T18:52:21,520 INFO [main] org.apache.druid.sql.calcite.BaseCalciteQueryTest - row #2: [a, 3] 2020-06-18T18:52:21,520 INFO [main] org.apache.druid.sql.calcite.BaseCalciteQueryTest - row #3: [b, 3] ``` This test covers a ton more surface than just this condition since it tests it via a join to a broadcast `GlobalTableDataSource`. `CalciteQueryTest` may now test against an `IndexedTable` joinable version of the `numfoo` test datasource (without the metrics columns), which is wired up into the segment walker to mimic a broadcast segment that is present on the broker, so that in the `DruidSchema` it will be translated into a `GlobalTableDataSource` instead of a `TableDataSource`. <hr> This PR has: - [x] been self-reviewed. - [ ] 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/licenses.yaml) - [ ] 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. - [x] been tested in a test Druid cluster. <hr> ##### Key changed/added classes in this PR * `TopNQueryEngine` ---------------------------------------------------------------- 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]
