Automatic compaction ignores maxColumnsToMerge from the TuningConfig setting

[superivaj]

Affected Version

The setting maxColumnsToMerge was introduced in version 0.21.0 but the problem was identified on version 0.22.1.

Description

Configuring a DataSource with an automatic compaction that includes maxColumnsToMerge will make the automatic compaction to ignore this field. This field is important to reduce and optimize memory usage, particularly for data sources with many dimensions.

The bug has been identified on the following classes:

• server/src/main/java/org/apache/druid/client/indexing/ClientCompactionTaskQueryTuningConfig.java
• server/src/main/java/org/apache/druid/server/coordinator/UserCompactionTaskQueryTuningConfig.java

Both of these classes are missing the maxColumnsToMerge property.

A fix was implemented to add the missing property to these two classes in our environment (fork). The fix was tested succesfully.

Pull request with the fix: #12551

[superivaj]

The fix for this issue has been merged with the associated pull request.