Caching Strategy
A plan for storing frequently accessed data temporarily to reduce latency and server load while ensuring data freshness.
Definition
Caching strategies determine what to cache, where to cache it, and how long to keep it. Options include browser caches, CDN caches, application caches (Redis, Memcached), and database query caches—each serving different performance needs.
Effective caching balances performance gains against data staleness risk. Strategies include time-based expiration, cache invalidation on updates, and cache-aside patterns where applications manage cache population.
Why It Matters
Caching dramatically improves performance and reduces costs. Database queries taking 500ms can be served in 1ms from cache. CDN caching reduces origin server load by 90% or more.
Wrong caching causes bugs. Serving stale data frustrates users. Over-aggressive invalidation negates benefits. Strategy must align with data characteristics and user expectations.
Examples in Practice
Reddit caches rendered page fragments for 10 minutes. Most page views hit cache, reducing database load from billions to manageable levels while accepting slight content staleness.
An e-commerce site caches product data for 1 hour but immediately invalidates when inventory changes—balancing performance with accuracy for purchase-critical information.