BackendReel #29 · 4 Nov 2026

Cache kya hai? Mummy = Cache, Dadi = Database (Tech Parivaar Ep 1)

Cache ek fast memory layer hai jo baar baar maange jaane wale data ki copy paas rakhti hai. Cache hit par jawab turant milta hai; cache miss par data slow source (database) se aata hai aur agli baar ke liye cache mein save hota hai (cache-aside pattern). Expiry (TTL) zaroori hai taaki purana data na dikhe. Redis (in-memory store), CDN (edge par files) aur browser HTTP cache isi idea ke roop hain.

Links

MDN: HTTP caching browser aur CDN caching kaise kaam karti hai

Redis docs in-memory cache se shuruaat

Aaj ye karo

Browser DevTools > Network tab, page reload karo: Size column mein memory cache / disk cache dekho.
Redis local chalao: docker run -p 6379:6379 redis.
Expiry ke saath value rakho: SET user:1 Riya EX 60, phir GET user:1.
Pattern yaad rakho: pehle cache, miss ho toh database, phir result cache mein save (cache-aside).

docker run -p 6379:6379 redis

redis-cli SET user:1 Riya EX 60

redis-cli GET user:1

Sources

MDN, Redis docs; 4 Nov 2026 ko check kiya.