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Matthias J. Sax commented on KAFKA-14748: ----------------------------------------- Yes, the behavior would change. But make this change is the goal, isn't it? – That is also why I brought up the KIP question – if we apply a change in behavior, we might need a KIP. The other question was: if we apply with change of behavior (even if we do a KIP), and there are users who want to old behavior can they still get it. And I think the answer is yes, via upstream filtering. > Relax non-null FK left-join requirement > --------------------------------------- > > Key: KAFKA-14748 > URL: https://issues.apache.org/jira/browse/KAFKA-14748 > Project: Kafka > Issue Type: Improvement > Components: streams > Reporter: Matthias J. Sax > Priority: Major > > Kafka Streams enforces a strict non-null-key policy in the DSL across all > key-dependent operations (like aggregations and joins). > This also applies to FK-joins, in particular to the ForeignKeyExtractor. If > it returns `null`, it's treated as invalid. For left-joins, it might make > sense to still accept a `null`, and add the left-hand record with an empty > right-hand-side to the result. -- This message was sent by Atlassian Jira (v8.20.10#820010)