Key-value & caching

What if access is mostly by key?

Trade flexible queries for simple access paths, low latency, expiration, partitioning, and predictable scale.

Systems compared

• Redis
• Memcached
• DynamoDB
• RocksDB

Open the engine

1. Hash tables and sorted maps
2. TTL and eviction
3. Persistence modes
4. Partition keys and hot keys
5. Replication and consistency

Reconstruction lab

Implement a cache, choose an eviction policy, and design a globally partitioned key-value workload.