Hi, I think your understanding is correct. Having multiple map states for a broadcasted stream gives more flexibility. You can have states of different key and value types and store completely different information in them.
Fabian Am Fr., 12. Apr. 2019 um 20:30 Uhr schrieb M Singh <mans2si...@yahoo.com>: > Hi Fabian: Thanks for your answer. > > From my understanding (please correct me), in the example above, we are > passing map descriptors to the same broadcast stream. So, the > elements/items in that stream will be the same. The only difference would > be that in the processBroadcastElement method of the > KeyedBroadcastProcessFunction impl, we could add different mappings of > broadcast element (from the same broadcasted stream) to different map > states. I am looking at the documentation example ( > https://ci.apache.org/projects/flink/flink-docs-release-1.8/dev/stream/state/broadcast_state.html) > and still not sure how that will help ? > > Thanks for your help. > > Mans > > > > > > On Thursday, April 11, 2019, 3:53:59 AM EDT, Fabian Hueske < > fhue...@gmail.com> wrote: > > > Hi, > > you would simply pass multiple MapStateDescriptors to the broadcast method: > > MapStateDescriptor<A, B> bcState1 = ... > MapStateDescriptor<C, D> bcState2 = ... > > DataStream<X> stream = ... > BroadcastStream<X> bcStream = stream.broadcast(bcState1, bcState2); > > Best, > Fabian > > > Am Mi., 10. Apr. 2019 um 19:44 Uhr schrieb M Singh <mans2si...@yahoo.com>: > > Hi Guowei; > > Thanks for your answer. > > Do you have any example which illustrates using broadcast is used with > multiple descriptors ? > > Thanks > > > > On Sunday, April 7, 2019, 10:10:15 PM EDT, Guowei Ma <guowei....@gmail.com> > wrote: > > > Hi > 1. I think you could use "Using Managed Operator State"[1] > (context.getOperatorStateStore().getBroadcastState()) to use the > BroadCastState. But you must use it very carefully and guarantee the > semantics of broadcast state yourself. I think "The Broadcast State > Pattern"[2] is some best practice for using broadcast state. > 2. The broadcast function is varargs. Since that you could pass multiple > MapStateDescriptors to it. > > [1] > https://ci.apache.org/projects/flink/flink-docs-release-1.7/dev/stream/state/state.html#using-managed-operator-state > [2] > https://ci.apache.org/projects/flink/flink-docs-release-1.7/dev/stream/state/broadcast_state.html > > Best, > Guowei > > > M Singh <mans2si...@yahoo.com> 于2019年4月7日周日 下午10:17写道： > > Hi Flink folks: > > I am reading the documentation on broadcast state pattern ( > https://ci.apache.org/projects/flink/flink-docs-release-1.7/dev/stream/state/broadcast_state.html) > and have following questions: > > 1. Point number 2 - '2. it is only available to specific operators that > have as inputs a *broadcasted* stream and a *non-broadcasted* one,'. > From what I understand it can be used with connected streams. Is there any > other operator where it can be used ? > > 2. Point number 3 - '3. such an operator can have *multiple broadcast > states* with different names.'. Is there any additional > documentation/example on how to implement/use multiple broadcast states ? > > Thanks > > Mans > >
