Caching Study Portal

Key takeaways

• Every caching question is a staleness-tolerance question. Answer that first.
• Content-hashed URLs make invalidation unnecessary; the HTML entry point must stay no-cache.
• Cache-aside is the default; write-through when reads reliably follow writes; write-behind only where losing writes is acceptable.
• Stampede fixes compose: single-flight, TTL jitter, and serve-stale-while-revalidating.
• Hot keys are immune to cluster scaling. Use a short-lived local cache or split the key.
• TTL is the bound on how wrong you may be, so it is chosen from business tolerance.
• On write, delete the entry rather than updating it, unless you can guarantee ordering.