One Log, Four Views, Four Contracts Diagram

Single Publication

One ordered log carries every committed change exactly once in order
No view is written synchronously inside the order request
Each consumer group reads the same stream at its own pace

Freshness Contracts

Cache invalidates by key and is fresh within seconds
Search consumes events and is fresh within tens of seconds
Report and model follow batch cycles, not single orders

Rebuild From the Log

A dropped cache or index replays the log from the oldest needed offset
Replay converges because every apply is idempotent
The retention horizon bounds how far back a rebuild can go