Hi Community, We are working on support of distinct aggregators over data stream on Table/SQL API. Currently there are seems to be many JIRAs related to distinct agg over stream use cases which are still pending (FLINK-6249 <https://issues.apache.org/jira/browse/FLINK-6249>, FLINK-6260 <https://issues.apache.org/jira/browse/FLINK-6260>, FLINK-5315 <https://issues.apache.org/jira/browse/FLINK-5315>, FLINK-6335 <https://issues.apache.org/jira/browse/FLINK-6335>, FLINK-6373 <https://issues.apache.org/jira/browse/FLINK-6373>, FLINK-6250 <https://issues.apache.org/jira/browse/FLINK-6250>, etc) and I am having some concerns when trying to come up with a solution as there might be other use cases out there.
I summarized a write up and categorized the use cases into unbounded or bounded aggregations and proposed a solution through modifying and adding new distinct aggregate functions using UDAGG API with DataView. Please find it here <https://docs.google.com/document/d/1zj6OA-K2hi7ah8Fo-xTQB-mVmYfm6LsN2_NHgTCVmJI/edit?usp=sharing> . Any comments or suggestions are highly appreciated. Many Thanks, Rong
