KIP-232 — Detect outdated metadata using leaderEpoch and partitionEpoch

Discussion ClientProtocol

Proposes embedding `leaderEpoch` and `partitionEpoch` into `MetadataResponse` and using them client-side to discard stale metadata fetched from a broker that has not yet processed the latest `UpdateMetadataRequest`. Concurrent `UpdateMetadataRequest` delivery to brokers creates a window where clients fetch old leader epoch data, causing `OffsetOutOfRangeException` in consumers and MirrorMaker position rewinds with no actual log truncation.

Protocol Impact

Fetch · Metadata · LeaderAndIsr · UpdateMetadata · OffsetCommit · OffsetFetch

Details