Your App Isn’t Slow — Your Caching Strategy Is Broken
Most devs blame code for performance issues
Wrong.
You're just hitting the DB too often.
What caching does
- Store frequently used data
- Avoid repeated DB calls
- Serve responses instantly
Basic flow
- User requests data
- Check cache
- If present → return instantly (cache hit)
- If not → fetch from DB (cache miss)
- Store in cache
- Return response
That's the entire game.
Cache hit vs miss
Cache hit → fast response (milliseconds)
Cache miss → slow response (DB query)
Your entire system performance depends on this.
Redis basics
- In-memory → super fast
- Key-value store
- Supports TTL
- Used everywhere at scale
Biggest problem
Cache invalidation
Data updates
Cache doesn’t
→ stale results
Common Caching Strategies
Cache Aside (Most Common)
App checks cache first
On miss → fetch from DB → update cache
Simple. Flexible. Widely used.Write Through
Write goes to cache AND DB together
Safer, but slower writes.Write Back (Advanced)
Write goes to cache first
DB updated later
Fast, but risky if not handled well.
Golden rules
- Always use TTL
- Don’t cache everything
- Handle misses properly
- Never treat cache as DB
Caching isn’t optional at scale
It’s the difference between smooth and broken systems
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