Memcached

Memcached is a high-performance, distributed memory object caching system. It is simpler than Redis. It does arguably one thing: Key-Value caching of strings/objects in RAM.

When to Use

• Simple Caching: Pure LRU cache.
• Multi-Threaded: Memcached is multi-threaded (Redis is single-threaded). It scales vertically better on massive multicore machines for simple GET/SET throughput.
• Session Cache: Storing web sessions.

Quick Start

# Telnet interface
set mykey 0 60 4
data
STORED

get mykey
VALUE mykey 0 4
data
END

Core Concepts

Slab Allocation

Memcached manages memory in "Classes" of chunks (Slabs) to prevent fragmentation.

LRU (Least Recently Used)