Major Description
Kafka Streams supports three types of joins:
- KStream-KStream
- KStream-KTable
- KTable-KTable
Furthermore, Kafka Streams supports the join variant, namely
- inner join
- left join
- outer join
Not all combination of "type" and "variant" are supported.
The problem is, that the semantics of the different joins do use different semantics (and are thus inconsistent).
With this ticket, we want to
- introduce unique semantics over all joins
- improve handling of "null"
- add missing inner KStream-KTable join
See KIP-76 for more details: https://cwiki.apache.org/confluence/display/KAFKA/KIP-76%3A+Improve+Kafka+Streams+Join+Semantics
