Caching Patterns

A well-placed cache is the cheapest way to buy speed. A misplaced cache is the most expensive way to buy bugs.

Cache Strategies

Strategy	How It Works	When to Use
Cache-Aside (Lazy)	App checks cache → miss → reads DB → writes to cache	Default choice — general purpose
Read-Through	Cache fetches from DB on miss automatically	ORM-integrated caching, CDN origin fetch
Write-Through	Writes go to cache AND DB synchronously	Read-heavy with strong consistency
Write-Behind	Writes go to cache, async flush to DB	High write throughput, eventual consistency OK
Refresh-Ahead	Cache proactively refreshes before expiry	Predictable access patterns, low-latency critical

Cache-Aside Flow:

  App ──► Cache ──► HIT? ──► Return data
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