Redis Caching Strategies: Boost Your App Performance

The fastest database query is the one you never make. Redis is an in-memory store that serves data in microseconds.

Strategy 1: Cache-Aside (Lazy Loading)

This is the most common pattern.

1. App checks Redis.
2. Miss: App queries DB, saves to Redis, returns to user.
3. Hit: App returns data from Redis immediately.

const cached = await redis.get('user:123');
if (cached) return JSON.parse(cached);

const user = await db.findUser(123);
await redis.set('user:123', JSON.stringify(user), 'EX', 3600); // 1 hour TTL
return user;

Strategy 2: Write-Through

Update the DB and Cache at the same time. Ensures consistency but adds write latency.

Eviction Policies

What happens when Redis is full?

• LRU (Least Recently Used): Deletes items that haven't been asked for in a while.
• TTL (Time To Live): Auto-delete items after X seconds.

Use Redis wisely, and your users will feel the speed.