Hi everyone, I am currently thinking about a use case for a streaming job and, while I'm fairly certain it cannot be done with the APIs that Flink currently provides, I figured I'd put it out there in case other users think something like this would be useful to a wider audience.
The current broadcasting mechanisms offered by Flink mention use cases where "control events" are needed. In my case I would also have control events, and I would need to broadcast them to *all parallel instances* of any downstream operators that consume the events. However, some of those operators have to be keyed because they are stateful. From the API's point of view, I'd imagine something like controlStream.connect(mainStream).broadcastFirstKeySecondBy(keySelector).process(PartiallyKeyedCoProcessFunction) The function would also have something like processElement1 and processElement2, but one of those methods wouldn't have access to partitioned state (or could it have access to state for all key groups handled by that instance?). Since I'm not familiar with all of Flink's internals, I don't know if this would be even remotely feasible, but I'd like to know if others have opinions on this. Regards, Alexis.
