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Bruno Cadonna commented on KAFKA-10137: --------------------------------------- I also noticed this the last time I looked at {{ChangeLoggingWindowBytesStore}}. Since the sequence number is not incremented if {{retainDuplicates}} is false, I think it is OK from a correctness point of view. Maybe the reason why we write the sequence number also when {{retainDuplicates}} is false is that in such a way we do not need to distinguish whether the key has a sequence number or not when we read the keys again. > Clean-up retain Duplicate logic in Window Stores > ------------------------------------------------ > > Key: KAFKA-10137 > URL: https://issues.apache.org/jira/browse/KAFKA-10137 > Project: Kafka > Issue Type: Task > Components: streams > Affects Versions: 2.5.0 > Reporter: Bruno Cadonna > Priority: Minor > > Stream-stream joins use the regular `WindowStore` implementation but with > `retainDuplicates` set to true. To allow for duplicates while using the same > unique-key underlying stores we just wrap the key with an incrementing > sequence number before inserting it. > The logic to maintain and append the sequence number is present in multiple > locations, namely in the changelogging window store and in its underlying > window stores. We should consolidate this code to one single location. -- This message was sent by Atlassian Jira (v8.3.4#803005)