A complete guide to Redis in Ruby — String, Hash, List, Set, Sorted Set, HyperLogLog, and Stream data structures, connections and connection pools, TTL and expiry strategies, the fetch caching pattern, distributed locks with SETNX, pub/sub, Lua scripting, pipelining and multi/exec, Rails integration with redis-rails and Sidekiq, Redis Cluster, and monitoring.
A complete guide to Memcached in Ruby — installing the dalli gem, connections and connection pools, basic cache CRUD, CAS for atomic updates, namespaces and key versioning, large data compression, Rails cache store integration, session stores, fragment caching, LRU eviction strategies, cache consistency with stampede prevention, and a Memcached vs Redis comparison.