Caching Strategy
The chosen pattern for how a cache is populated, read and invalidated — cache-aside, read-through, write-through or write-behind.
Cache-aside (lazy loading) — the application checks the cache, and on a miss reads the source and populates it. The default: simple, only caches what is used, and tolerates cache unavailability. It has a known race between a reader populating and a writer invalidating.
Read-through — the cache itself loads on a miss. Same behaviour, less application code, and the cache becomes a hard dependency.
Write-through — every write goes through the cache to the store. The cache is never stale, at the cost of write latency and of caching data that may never be read.
Write-behind — write to the cache, flush asynchronously. Fastest writes, and it risks data loss if the cache dies before the flush. Reserve it for data that can be reconstructed.
The layer choice matters as much as the pattern: browser, CDN, gateway, application in-process, and shared cache each have different invalidation reach. The cheapest cache hit is the one that never leaves the client.