Oh wow, I had read that documentation so many times and I was sure that API also expected the broadcasted side to have a key like the other side, but that's not the case, that is already what I was thinking of. Thanks.
Regards, Alexis. On Wed, 12 Oct 2022, 03:42 仙路尽头谁为峰, <xljtswf2...@163.com> wrote: > Hi Alexis: > > The broadcast state pattern should be done by calling connect() on > the non-broadcasted stream, with the *broadcaststream* as an argument. > > And if the main stream is keyedStream, then the processElement > function will have access to any keyed state as normal keyedstream. > > > > Best Regards! > > 从 Windows 版邮件 <https://go.microsoft.com/fwlink/?LinkId=550986>发送 > > > > *发件人: *Alexis Sarda-Espinosa <sarda.espin...@gmail.com> > *发送时间: *2022年10月12日 4:11 > *收件人: *user <user@flink.apache.org> > *主题: *Partial broadcast/keyed connected streams > > > > 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. > > > > >
