Re: The Role of TimerService in ProcessFunction
Thanks for the clarification Dawid. Resolves my confusion. Sent from Yahoo Mail on Android On Fri, 19 Mar 2021 at 2:41 pm, Dawid Wysakowicz wrote: Hi Chirag, I agree it might be a little bit confusing. Let me try to explain the reasoning. To do that I'll first try to rephrase the reasoning from FLINK-8560 for introducing the KeyedProcessFunction. It was introduced so that users have a typed access to the current key via Context and OnTimerContext. This is actually the only difference between the two function. Somewhat as a consequence of the above, the KeyedProcessFunction can be used solely on a keyed stream, however ProcessFunction can be used in both. That was actually the only way to use a ProcessFunction on a keyed stream prior to introducing the KeyedProcessFunction. If you don't need access to the current key you should be fine with using the ProcessFunction on a keyed stream and there you can use the TimerService. It is advised to use a KeyedProcessFunction on a keyed stream, however for backwards compatibility the old behaviour has been kept. Hope that it clarifies the things a bit. Best, Dawid On 17/03/2021 07:47, Chirag Dewan wrote: Hi, Currently, both ProcessFunction and KeyedProcessFunction (and their CoProcess counterparts) expose the Context and TimerService in the processElement() method. However, if we use the TimerService in non keyed context, it gives a runtime error. I am a bit confused about these APIs. Is there any specific reason for exposing TimerService in non-keyed context especially if it cant be used without keyed stream? Any leads are much appreciated. Thanks, Chirag
Re: The Role of TimerService in ProcessFunction
Hi Chirag, I agree it might be a little bit confusing. Let me try to explain the reasoning. To do that I'll first try to rephrase the reasoning from FLINK-8560 for introducing the KeyedProcessFunction. It was introduced so that users have a typed access to the current key via Context and OnTimerContext. This is actually the only difference between the two function. Somewhat as a consequence of the above, the KeyedProcessFunction can be used solely on a keyed stream, however ProcessFunction can be used in both. That was actually the only way to use a ProcessFunction on a keyed stream prior to introducing the KeyedProcessFunction. If you don't need access to the current key you should be fine with using the ProcessFunction on a keyed stream and there you can use the TimerService. It is advised to use a KeyedProcessFunction on a keyed stream, however for backwards compatibility the old behaviour has been kept. Hope that it clarifies the things a bit. Best, Dawid On 17/03/2021 07:47, Chirag Dewan wrote: > Hi, > > Currently, both ProcessFunction and KeyedProcessFunction (and their > CoProcess counterparts) expose the Context and TimerService in the > processElement() method. However, if we use the TimerService in non > keyed context, it gives a runtime error. > > I am a bit confused about these APIs. Is there any specific reason for > exposing TimerService in non-keyed context especially if it cant be > used without keyed stream? > > Any leads are much appreciated. > > Thanks, > Chirag OpenPGP_signature Description: OpenPGP digital signature
The Role of TimerService in ProcessFunction
Hi, Currently, both ProcessFunction and KeyedProcessFunction (and their CoProcess counterparts) expose the Context and TimerService in the processElement() method. However, if we use the TimerService in non keyed context, it gives a runtime error. I am a bit confused about these APIs. Is there any specific reason for exposing TimerService in non-keyed context especially if it cant be used without keyed stream? Any leads are much appreciated. Thanks,Chirag
