Hi Chen, thanks for this interesting proposal. I think side output would be a very valuable feature to have!
I went of the FLIP and have a few questions. - Will multiple side outputs of the same type be supported? - If I got it right, the FLIP proposes to change the signatures of many user-defined functions (FlatMapFunction, WindowFunction, ...). Most of these interfaces/classes are annotated with @Public, which means we cannot change them in the Flink 1.x release line. What would be alternatives? I can think of a) casting the Collector into a RichCollector (as you do in your prototype) or b) retrieve the RichCollector from the RuntimeContext that a RichFunction provides. I'm not so familiar with the internals of the DataStream API, so I leave comments on that to other. Best, Fabian 2016-10-25 18:00 GMT+02:00 Chen Qin <c...@uber.com>: > Hey folks, > > Please give feedback on FLIP-13! > https://cwiki.apache.org/confluence/display/FLINK/FLIP- > 13+Side+Outputs+in+Flink > JIRA task link to google doc > https://issues.apache.org/jira/browse/FLINK-4460 > > Thanks, > Chen Qin >
