Invalidazzjoni tal-cache — iż-żamma tal-data cached konsistenti mal-sorsa tal-verità — hija famuża bħala waħda mill-aktar problemi diffiċli fil-komputazzjoni. L-isfida hija li tiżgura li l-caches ma jservux data stali filwaqt li tibalanċja l-prestazzjoni, il-konsistenza, u l-kumplessità. Hemm bosta strateġiji u pitfalls li jiswa l-fehim.
Il-problema fundamentali
When the source data changes, the cached copy becomes STALE.
→ Serve stale data? (fast but wrong) vs invalidate? (consistent but complex/slower)
→ "There are only two hard things in CS: cache invalidation and naming things."
The difficulty: knowing WHEN and WHAT to invalidate, across distributed systems,
without races, while keeping good cache hit rates.
