KIP-532 — Broker Consumer Lag metrics in size and time

Discussion MetricsConsumer

Proposes broker-side consumer lag metrics expressed in both message count and estimated time-behind-tail, using PageCache hit/miss signals to infer whether consumer fetches are served from cache or disk. Existing consumer lag metrics are client-side only; brokers have no intrinsic view of how far behind consumers are or whether they are about to fall off the PageCache, which degrades fetch performance.

Protocol Impact

Fetch

Details