لماذا ومتى نخزّن مؤقتًا

في هذا الدرس

know the layers where a cache can sit and what each one saves.

الموضوعات المخطط لها

• A cache keeps a copy of an expensive result close to the caller. It trades freshness for speed and load.
• Layers: browser/client (no request at all), CDN (no trip to origin), gateway (no call to the service), application (no database call), database (buffer pool, query cache).
• The closer to the user, the more you save, and the harder invalidation becomes.
• Cache only data that is read often, changes rarely, and is costly to produce.