Hi Flavio,
the reason is that under the covers the ReduceFunction will be used as
the ReduceFunction of a ReducingState. And those cannot be rich
functions because we cannot provide all the required context "inside"
the state backend.
You can see how the ReduceFunction is used to create a
ReducingStateDescriptor here:
https://github.com/apache/flink/blob/0c43649882c831c1ec88f4e33d8a59b1cbf5f2fe/flink-streaming-java/src/main/java/org/apache/flink/streaming/api/datastream/AllWindowedStream.java#L300
Best,
Aljoscha
On 16.07.20 16:28, Flavio Pompermaier wrote:
Hi to all,
I'm trying to apply a rich reduce function after a countWindowAll but Flink
says
"ReduceFunction of reduce can not be a RichFunction. Please use
reduce(ReduceFunction, WindowFunction) instead."
Is there any good reason for this? Or am I doing something wrong?
Best,
Flavio
