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Patrik Kleindl commented on KAFKA-12909: ---------------------------------------- [~mjsax] Is it planned to un-deprecate the previous methods? If not, the opt-in would become mandatory with the next major release. Is there any way with the new methods to get the same behaviour as before, e.g. instant results? > Allow users to opt-into spurious left/outer stream-stream join improvement > -------------------------------------------------------------------------- > > Key: KAFKA-12909 > URL: https://issues.apache.org/jira/browse/KAFKA-12909 > Project: Kafka > Issue Type: Improvement > Components: streams > Reporter: Matthias J. Sax > Assignee: Matthias J. Sax > Priority: Blocker > Fix For: 3.1.0 > > > https://issues.apache.org/jira/browse/KAFKA-10847 improves left/outer > stream-stream join, by not emitting left/outer results eagerly, but only > after the grace period passed. > While this change is desired, there is an issue with regard to upgrades: if > users don't specify a grace period, we fall back to a 24h default. Thus, > left/outer join results would only be emitted 24h after the join window end. > This change in behavior could break existing applications when upgrading to > 3.0.0 release. – And even if users do set a grace period explicitly, it's > still unclear if the new delayed output behavior would work for them. > Thus, we propose to disable the fix of KAFAK-10847 by default, and let user > opt-into the fix explicitly instead. > To allow users to enable the fix, we want to piggy-back on KIP-633 > (https://issues.apache.org/jira/browse/KAFKA-8613) that deprecated the > existing `JoinWindows.of()` and `JoinWindows#grace()` methods in favor of > `JoinWindows.ofSizeAndGrace()` – if users don't update their code, we would > keep the fix disabled, and thus, if users upgrade their app nothing changes. > Only if users switch to the new `ofSizeAndGrace()` API, we enable the fix and > thus give users the opportunity to opt-in expliclity and pick an appropriate > grace period for their application. -- This message was sent by Atlassian Jira (v8.20.1#820001)