Is this comment in the file
flink-streaming-java/src/main/java/org/apache/flink/streaming/api/datastream/CoGroupedStreams.java
accurate?
" * <p>Note: Right now, the groups are being built in memory so you need to
ensure that they don't
* get too big. Otherwise the JVM might crash."
Looking at the source code of CoGroupedStreams, i see that it simply does a
map, union and then the data is assigned to appropriate windows. I assumed
that the persistence of elements in the window itself is done using my
configured state backend (and that appends do not need to read the entire
list state).
I ask because i tried setting a uid on my cogroup operator like below and
this results in a compilation error(no uid method available?)
firstStream
.coGroup(secondStream)
.where(_.id)
.equalTo(_.id)
.window(TumblingEventTimeWindows.of(Time.seconds(1)))
.apply(new MyCogroupFunction())
.uid("myCogroup")
Is the comment referring to having enough memory on the read side? If so,
isn't this true for any window process function?
Thanks
Sudharsan
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