LEARN. PRACTICE. GROW.Concept and mechanism
Delivering a message and completing its effect are different events. With PeekLock, the consumer communicates completion to the broker but can lose its connection after commit and before Complete. Redelivery should recognize already-completed work. Send duplicate detection has its own scope and window; it does not replace consumer idempotency. For events, arrival order can differ from business order. Define versions and duplicate handling instead of assuming infrastructure serializes every entity change.
Guided application
In Event Hubs, consumer groups support applications with independent progress. Checkpoints should reflect durable effects according to the recovery contract; advancing early can skip work after failure. Dead-letter handling requires diagnosis and controlled replay, not blind resending. At HTTP entry, APIM can validate JWTs and limit traffic. Issuer and audience restrictions belong to the contract, while distributed throttling is not an exact financial counter. RUN needs to understand backlog, retention, replay criteria, and who decides about unprocessable messages.
The worker persisted the result but lost Complete. On redelivery, it checks the persisted ID before repeating any external effect.
Common pitfalls
Checkpointing before commit; using rate limits as billing; resending dead letters without removing the cause.
Related topics: Versions and controlled deployment · Functions, failures, and safe repetition
Progress is useful only when it corresponds to demonstrable and recoverable effects.
Reference: Service Bus settlement · AZ-204 archived objectives 2026-01-14; retired 2026-07-31