X-czh opened a new pull request, #24925: URL: https://github.com/apache/flink/pull/24925
## What is the purpose of the change Reverting previous changes that break state compatibility. [FLINK-34123](https://issues.apache.org/jira/browse/FLINK-34123) & [FLINK-35068](https://issues.apache.org/jira/browse/FLINK-35068) introduced built-in dedicated serialization support for Maps, Sets, Lists, and Collections. However, if a user defines a collection-typed value in state, the default serializer is changed from Kryo to dedicated serializer, breaking compatibility. Furthermore, since RocksDBStateBackend does not support serialization format change for the keys in MapState, we cannot implement a fully-compatible solution for this case. ## Brief change log Revert the following three commits: 1. [FLINK-34123][core][type] Introduce built-in serialization support for Map, List, and Collection 2. [FLINK-34123][docs][type] Add doc for built-in serialization support for Map, List, and Collection 3. [FLINK-35068][core][type] Introduce built-in serialization support for java.util.Set -- 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: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org