Beginner LevelSystem Design & Architecture
What are Caching Strategies (Cache-Aside, Read-Through, Write-Through, Write-Back)?
❓ Interview Prompt: Compare Caching Patterns: Cache-Aside (Lazy Loading), Read-Through, Write-Through, and Write-Back (Write-Behind).
Selecting appropriate caching patterns balances read latency, write performance, and data consistency:
•
Cache-Aside (Lazy Loading): Application queries Cache. If Cache Miss $\rightarrow$ Reads Database $\rightarrow$ Writes to Cache $\rightarrow$ Returns. Highly resilient.
•
Read-Through: Application reads exclusively from Cache. The cache transparently fetches missing keys from DB.
•
Write-Through: Application writes to Cache; Cache synchronously writes to DB before returning success.
•
Write-Back (Write-Behind): Application writes to Cache; Cache asynchronously queues DB writes in the background (Fastest writes, risk of data loss on cache crash).
Code Implementation Example
typescript
// Cache-Aside (Lazy Loading) Implementation
export async function getCachedUser(id: string) {
const cached = await redis.get('user:\${id}');
if (cached) return JSON.parse(cached);
const user = await db.user.findUnique({ where: { id } });
await redis.setex('user:\${id}', 3600, JSON.stringify(user));
return user;
}💡Implementing Cache-Aside lazy loading pattern in TypeScript.
🎯 Interview Key Takeaway
Use Cache-Aside for read-heavy workloads, Write-Through for strict data consistency, and Write-Back for high write throughput.
#System Design#Caching#Cache-Aside#Write-Through#Beginner
Back to all System Design & Architecture Questions→