Backend & systems·Caching and invalidation
you changed the row and now you have to hunt down every cached copy of it before someone reads the old one.
Cache invalidation
The problem of removing or updating cached entries once the underlying data changes. It is hard because the set of cache keys derived from one row is rarely obvious: a single user update can invalidate their profile, three list pages, a search result and a rendered fragment. Most production bugs blamed on caching are really a key you forgot to invalidate.