Thanks for the clarification Dawid. Resolves my confusion.
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On Fri, 19 Mar 2021 at 2:41 pm, Dawid Wysakowicz<dwysakow...@apache.org>
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
