Invalidation Model¶

Invalidation removes local L1 entries from peer application instances after data changes.

flowchart LR
    A["Instance A changes data"] --> Local["Remove local L1 key"]
    Local --> Bus["Publish invalidation"]
    Bus --> B["Instance B removes L1 key"]
    Bus --> C["Instance C removes L1 key"]
    Bus -. ignored by source .-> A

Each running cache instance has a source identity. When it publishes an invalidation message, other instances apply it and the sender ignores its own message. This prevents a process from doing duplicate work for the change it already made locally.

Invalidation messages support two actions:

Invalidation is separate from distributed storage. A Redis distributed cache stores shared values; an invalidation bus tells local process caches when to drop stale local copies.