Intermediate LevelSoftware Engineering Principles
Compare Cache-Aside (Lazy Loading), Read-Through, Write-Through, and Write-Behind caching strategies.
❓ Interview Prompt: Compare caching patterns: Cache-Aside (Lazy Loading), Read-Through, Write-Through, and Write-Behind (Write-Back) caching.
Evaluating caching strategies:
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Cache-Aside (Lazy Loading): Application queries Cache. If Cache Miss $\rightarrow$ Query Database $\rightarrow$ Save to Cache $\rightarrow$ Return. Highly resilient; cache failure doesn't halt app.
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Read-Through: Application reads exclusively from Cache. Cache transparently fetches missing data from DB.
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Write-Through: Application writes data to Cache. Cache synchronously updates Database before returning.
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Write-Behind (Write-Back): Application writes data to Cache. Cache asynchronously queues database writes in background (High write speed, risk of data loss on cache crash).
Code Implementation Example
typescript
// Cache-Aside (Lazy Loading) Pattern
export async function getUser(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 the Cache-Aside (Lazy Loading) pattern in Node.js.
🎯 Interview Key Takeaway
Use Cache-Aside for general read-heavy workloads, and Write-Behind for extreme write throughput where minor data loss is acceptable.
#Caching#Cache-Aside#Write-Through#Intermediate
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