# Memcached

> Memcached distributed memory caching. Use for simple caching.

- Skill: `g1joshi/memcached` (Agent Skill)
- Install (CLI): `npx skillmds@latest add g1joshi/memcached`
- Raw SKILL.md: https://api.skillmd.com/api/skills/g1joshi/memcached/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: G1Joshi (https://skillmd.com/u/g1joshi)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/g1joshi/memcached

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# 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

```bash
# 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)

When full, it evicts the oldest unused items.

### No Persistence

If you restart, data is gone.

## Best Practices (2025)

**Do**:

- **Use for huge read-heavy loads**: Facebook uses it heavily.
- **Use Serialization**: Store Protobuf or msgpack for efficiency.

**Don't**:

- **Don't use as a Datastore**: It is a cache _only_.
- **Don't use iterating**: You cannot "List all keys". You must know the key to get the value.
- **Comparison to Redis**: In 2025, Redis is generally preferred for features. Use Memcached if you specifically need multi-threaded scaling for pure String caching.

## References

- [Memcached Wiki](https://github.com/memcached/memcached/wiki)