Delivery Assurance: Retention and Delivery

A persistence store adds value by strengthening message delivery assurances. You could imagine a persistence store as a bus that can retain its message stream for subscribers that are temporarily unavailable.

Store for Message Recovery

In the first frame of the preceding diagram, the durable subscriber is unavailable, so it misses messages from the publisher. The persistence store collects those messages (1). In the second frame, the durable subscriber resumes, recovers the missed messages from the store (2), then continues receiving messages directly from the publisher (3).

Related concepts