Practical caching patterns (Cache-Aside, Write-Through), cache stampede prevention, and Redis distributed locks.
In-memory data structures in Redis provide sub-millisecond data access that protects relational databases from high-concurrency spikes.
### Mitigating Cache Stampede with Probabilistic Early Expiration
When a popular cache key expires during flash sales, thousands of simultaneous requests can hit the database. Implementing early background cache renewal (XFetch algorithm) eliminates stampedes.
### Distributed Locks for Critical Sections
Use the Redlock algorithm to guarantee that operations like inventory allocation, voucher redemptions, and order charging execute atomically across multiple backend server nodes.
