KIP-345 — Introduce static membership protocol to reduce consumer rebalances

Accepted Kafka 2.3 Consumer

Introduces static consumer group membership via a `group.instance.id` configuration, allowing a consumer to rejoin after a restart with its previous member identity and partition assignment without triggering a group rebalance. Every consumer restart or temporary disconnect causes a full group rebalance, which for stateful Streams applications means expensive state migration and processing downtime proportional to the number of group members.

Protocol Impact

Heartbeat · JoinGroup · OffsetCommit · SyncGroup · LeaveGroup · DescribeGroups · FindCoordinator

Details