Matthias J. Sax created KAFKA-12317: ---------------------------------------
Summary: Relax non-null key requirement for left KStream-KTable join Key: KAFKA-12317 URL: https://issues.apache.org/jira/browse/KAFKA-12317 Project: Kafka Issue Type: Improvement Components: streams Reporter: Matthias J. Sax Currently, for a stream-table join KafkaStreams drops all stream records with a null-key, because for a null-key the join is undefined: ie, we don't have an attribute the do the table lookup (we consider the stream-record as malformed). Note, that we define the semantics of _left_ join as: keep the stream record if no KTable record was found. We could relax the definition of _left_ join though, and not drop non-key stream records, and call the ValueJoiner with a `null` table record instead: if the stream record key is `null`, we could treat is as "failed table lookup" instead of treating the stream record as corrupted. If we make this change, users that want to keep the current behavior, can add a `filter()` before the join to drop `null`-key records from the stream explicitly. -- This message was sent by Atlassian Jira (v8.3.4#803005)