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Trevor Huey commented on KAFKA-3705: ------------------------------------ Similar to [~vultron81] mentioned, we're also using debezium, and being unable to do non-key joins is a huge pain point for us. [~jfilipiak], is this the PR you're referring to? https://github.com/apache/kafka/pull/3720. Looking through the comments, it appears there are a bunch of discussion items. I'm not familiar with the Kafka dev process, but is there anything I can do to help move this along? > Support non-key joining in KTable > --------------------------------- > > Key: KAFKA-3705 > URL: https://issues.apache.org/jira/browse/KAFKA-3705 > Project: Kafka > Issue Type: Bug > Components: streams > Reporter: Guozhang Wang > Labels: api > > Today in Kafka Streams DSL, KTable joins are only based on keys. If users > want to join a KTable A by key {{a}} with another KTable B by key {{b}} but > with a "foreign key" {{a}}, and assuming they are read from two topics which > are partitioned on {{a}} and {{b}} respectively, they need to do the > following pattern: > {code} > tableB' = tableB.groupBy(/* select on field "a" */).agg(...); // now tableB' > is partitioned on "a" > tableA.join(tableB', joiner); > {code} > Even if these two tables are read from two topics which are already > partitioned on {{a}}, users still need to do the pre-aggregation in order to > make the two joining streams to be on the same key. This is a draw-back from > programability and we should fix it. -- This message was sent by Atlassian JIRA (v6.4.14#64029)