One to Many outer join using KTable in Kafka
I have a table contact published to topic#1 with key as contact.id. Also a subtable is published to topic#2 with key as subtable.id. Now, I need to do a join like
select * from contact c outer join subtable st on c.id = st.id;
There is a 1..n relationship between the tables. How to perform a aggregation with/without lambda here.
Kafka Streams API does not support 1:n KTable-KTable joins yet (version
The only non-primary key join supported is a KStream-GlobalKTable join.
More details about join can be found in this blog post: https://www.confluent.io/blog/crossing-streams-joins-apache-kafka/
Also, there is a JIRA for 1:n joins: https://issues.apache.org/jira/browse/KAFKA-3705