KIP-1263 — Group Coordinator Assignment Batching and Offload

Accepted Kafka 4.3 ConsumerBroker

Moves consumer group partition assignment calculation from a synchronous, per-heartbeat computation to a batched, asynchronous offload executed by a dedicated thread pool in the group coordinator. The KIP-848 server-side assignor runs assignment on the broker's main thread during heartbeat processing, which for large groups (thousands of members) can block for hundreds of milliseconds and degrade broker latency.

Details