<Kafka streams: groupByKey and reduce not triggeri...

# stackoverflow

[user]

Kafka streams: groupByKey and reduce not triggering action exactly once when error occurs in stream
I have a simple kafka streams scenario where I am doing a groupyByKey then reduce and then an action. There could be duplicate events in the source topic hence the groupyByKey and reduce
The action could error and in that case I need the streams app to reprocess that event. In the example below I'm always throwing an error to demonstrate the point.
It is very important that the action only ever happens once and at least once.
The problem I'm finding is that when the streams app reprocesses...