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Module 4

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Caching

Speed up reads and reduce load: caching strategies, eviction policies, distributed caches, and the hardest problem in CS — cache invalidation.

7 lessons~84 min

What you'll learn

  • •Compare write-through, write-back, and write-around caching strategies
  • •Choose the right eviction policy for your access pattern
  • •Design a distributed caching layer with Redis or Memcached
  • •Handle cache invalidation without stale data issues
  • •Layer caches effectively: CDN, application, database query cache
1

Caching Strategies: Write-Through, Write-Back, Write-Around

The three fundamental caching write strategies, their consistency guarantees, performance characteristics, and ideal use cases.

12m
High
2

Cache Eviction Policies

LRU, LFU, FIFO, TTL, and random eviction. How each policy works, memory overhead, and when to pick one over another.

10m
High
3

Redis & Memcached

In-depth comparison of Redis and Memcached: data structures, persistence, clustering, pub/sub, and choosing between them.

15m
High
4

CDN Caching

How CDN edge caching works: cache headers (Cache-Control, ETag), cache keys, purging strategies, and dynamic content caching.

10m
Medium
5

Application-Level Caching

In-process caching, request-scoped caching, memoization, and computed caching. When local caches beat distributed ones.

10m
Medium
6

Cache Invalidation Patterns

The hardest problem in CS: TTL-based, event-driven, and versioned invalidation. Cache stampede prevention and stale-while-revalidate.

15m
High
7

Distributed Caching

Scaling caches across nodes: consistent hashing, replication, cache clusters, and handling node failures without cache avalanche.

12m
High
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