KIP-315 — Stream Join Sticky Assignor

Discussion StreamsConsumer

Proposes a StickyJoinAssignor for Kafka consumers doing stream-stream joins, ensuring co-partitioned topics always assign the same partition number to the same consumer while minimizing reassignment churn on rebalance. Standard assignors (RangeAssignor, RoundRobinAssignor) don't guarantee that co-partitioned topics land on the same consumer, which is a hard requirement for correct stream join semantics.

Details