Hi I'm pretty new to Flink and stream processing in general but I'm writing a thesis about it and I have a small question regarding WindowFunctions (WF). I have one large WF that does essentially two things: counting how much events there are in a window and calculating the difference between this and the previous window. And in the end I need the output of both calculations.
I'm in doubt if I should use one large WF that does both in combination with a simple count-WF to get the result of the count OR a small count-WF and a small diff-WF so that I can run the count-WF first and supply the result to both a sink and to the diff-WF. Graphically these are the two options: [image: Inline afbeelding 1] If I think about it every option has positive and negative sides: The blue option (Count-WF + Diff-WF): - + has more modularity and every WF does exactly one thing - - I need to do an extra KeyBy and Window operation for the Diff-WF with the same values as for the Count-WF (performance hit) While the red option (Count-WF + Large WF): - + might have better performance - - has less modularity So I would like the opinion of someone who has more experience with Flink that I have (so almost everybody here). Best regards, Maarten
