Hi,
My name is Viktor. I'm currently working with Kafka streams and have
several questions about Kafka and I can not find answers in the official
docs.
1. Why suppress functionality does not work with Hopping windows? How to
make it work?
Example of the code:
KStream<String, String> finalStream = source
.groupByKey()
.windowedBy(TimeWindows.of(Duration.ofSeconds(30)).advanceBy(Duration.ofSeconds(10)))
.reduce((aggValue, newValue) -> newValue,
Materialized.with(Serdes.String(), Serdes.String()))
.suppress(Suppressed.untilWindowCloses(Suppressed.BufferConfig.unbounded()))
.toStream();
finalStream.print(Printed.toSysOut());
finalStream.to(outputTopic);
After I run the code above - output stream is empty. There were no
errors/exceptions.
NOTE: With Tumbling Window the code working as expected.
Maybe I simply use it incorrectly?
2. Why with Hopping windows (without suppress) there are duplicates in the
output stream?
E.g., I send one record in the input kstream with Hopping window
(duration=30s, advanceBy=2s) but get two same records (duplicate) in the
output kstream.
Is that an expected behavior? If so, how can I filter/switch off these
duplicates?
3. Mainly I'm trying to solve this problem:
I have kstream with events inside and events can be repeated (duplicates).
In the output kstream I would like to receive only unique events for the
last 24 hours (window duration) with 1 hour window overlay (window
advanceBy).
Could you recommend me any examples of code or docs please?
I have already read official docs and examples but it was not enough to get
full understanding of how I can achieve this.
Best regards,
Viktor Markvardt
