Module 4

Caching Strategies

Learn how to dramatically improve performance with caching: from application-level patterns to CDNs and cache invalidation strategies.

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Cache-Aside Pattern

Check cache first, fetch from database on miss, then populate cache.

The most common caching pattern where the application manages the cache directly.

How It Works:

1Application checks cache first
2If cache miss, fetch from database
3Store result in cache
4Return data to user

Pseudocode:

data = cache.get(key)
if data is null:
    data = database.query(key)
    cache.set(key, data, TTL)
return data

Pros:

Application has full control
Cache only contains requested data
Resilient to cache failures

Cons:

Cache misses are slow (3 round trips)
Data can become stale
Application complexity increases

Best For:

Read-heavy workloads
Data that doesn't change frequently
When cache failures shouldn't break the app

Interactive: Cache Hit vs Miss

ClientCache(Redis)Database(PostgreSQL)

Click to simulate a request

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