What are the core concepts covered in Distributed Caching Patterns (Cache-Aside, Write-Through)?

Cache-Aside (Lazy loading) vs Write-Through vs Write-Behind; Cache stampede, cache penetration, and cache avalanche mitigation; Eviction policies: Least Recently Used (LRU) vs Least Frequently Used (LFU)

Advanced 22 min readModule: Module 3: Distributed Caching (Redis, Memcached, CDN)

Distributed Caching Patterns (Cache-Aside, Write-Through)

Accelerate reads to sub-milliseconds using Redis, CDN edge caching, and LRU eviction policies.

What You Will Learn in This Lesson

Cache-Aside (Lazy loading) vs Write-Through vs Write-Behind
Cache stampede, cache penetration, and cache avalanche mitigation
Eviction policies: Least Recently Used (LRU) vs Least Frequently Used (LFU)

Introduction & Core Concept

Caching stores copies of data in fast, in-memory hardware (like RAM) so that future requests for that data can be served faster.

WHY DOES THIS MATTER IN THE REAL WORLD?

Redis handles 100,000+ operations/second with sub-millisecond latency, shielding primary databases from read overload.

Cache-Aside Implementation Pattern

javascript

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async function getCourse(slug) {
  const cached = await redis.get(`course:${slug}`);
  if (cached) return JSON.parse(cached);
  
  const course = await db.query("SELECT * FROM courses WHERE slug = $1", [slug]);
  await redis.set(`course:${slug}`, JSON.stringify(course), "EX", 3600);
  return course;
}

Line-by-Line Technical Breakdown

1Phil Karlton famously said: 'There are only two hard things in Computer Science: cache invalidation and naming things.'

Try It Yourself (Interactive Editor)

Modify the code in real-time and click Run to test live browser output and console logs.

Intelligent Code Runner & Live Sandbox[JAVASCRIPT]

JAVASCRIPT SOURCE EDITOR

Interactive Live Code

>[JAVASCRIPT Runtime Initialized]

>Program compiled and executed with 0 errors.

>Output generated successfully.

Industry Best Practices & Professional Standards

Always set a Time-To-Live (TTL) on all cached keys to prevent stale data buildup.

Lesson Summary & Core Takeaways

Caching provides massive read speedups and protects persistent databases.