Side outputs for identical outputs Hi! Does anyone know if this works as expected in Flink 1.13?

val events = ... # Define data stream
val stream1 = events.process(...)
val stream2 = events.process(...)

The docs for side outputs says that "_[side outputs are] useful when you want to split a stream of data where you would normally have to replicate the stream_". I don't understand if side outputs are necessary if I just want to process the same stream with two different operators. Thanks for any comments!

we use side ouputs in 1.16, but the implementation is quite different to what you have there. Do you want to have multiple sinks?

Hi! Yes, the results from both "stream1" and "stream2" go to different sinks.

I can show you how we do it - hope it helps with your version

Thanks! I don't have any problem making it run, we can implement it with side outputs and it works fine. Just curious if side outputs are even needed in this case.

ah. I found no way at all to write to multiple sinks without side outputs. But I hear there are other ways. This is the recommended one afaik

If you want to fork a stream, sending all of the events down multiple paths, then the code you outlined is the perfect way to do it:

val events = ... # Define data stream
val stream1 = events.process(...)
val stream2 = events.process(...)

But if you want to split a stream, so that some events take one path and others take other paths, then you can either fork the stream as shown and then apply different filters to it:

val events = ... # Define data stream
val substream1 = events.filter1(...)
val substream2 = events.filter2(...)

Or you can use side outputs. One big advantage of side outputs is that the various output streams can have different types.

Thanks so much, it's very clear now 🙏