Hey, I am trying to understand kafka-streams and doing a simple prototype for joining KStream with KTable, but stuck at the error:
Invalid topology building: KSTREAM-MAP-0000000001 and KSTREAM-AGGREGATE-0000000004 are not joinable I tracked down the issue is thrown where stream or table have set sourceNodes to null, and confirmed both of them are null in my application. Interesting, when I initially read kafka topic into KStream, sourceNodes are not null, but later after doing simpel map operation (to exclude unneded fields an apply conversion) source nodes are deleted. Could someone clarify what sourceNodes are needed for and why they erased after map? Thanks! — Misha
