message idempotency

Architect

Feb 14, 2021 · Backend Development

Message Idempotency and Exactly‑Once Processing in RocketMQ

This article explains why message middleware like RocketMQ guarantees at‑least‑once delivery, the resulting duplicate‑delivery problem, and presents both transaction‑based and non‑transactional idempotency solutions—including select‑for‑update, optimistic locking, and a Redis‑backed deduplication table—to achieve exactly‑once semantics in distributed systems.