Redis

TL;DR

Qué: Almacén de estructuras de datos en memoria - caché, base de datos, broker de mensajes.

Por qué: Lecturas/escrituras ultra-rápidas, API simple, estructuras de datos versátiles.

Quick Start

Instalar:

# macOS
brew install redis
brew services start redis

# Ubuntu/Debian
sudo apt install redis-server
sudo systemctl start redis

# Docker
docker run -d --name redis -p 6379:6379 redis:7

Conectar:

redis-cli

# Remote
redis-cli -h hostname -p 6379 -a password

Operaciones básicas:

# String
SET name "Alice"
GET name

# With expiration (seconds)
SET session "abc123" EX 3600

# Check TTL
TTL session

# Delete
DEL name

Cheatsheet

Comando	Descripción
SET key value	Establecer valor string
GET key	Obtener valor string
DEL key	Eliminar clave
EXISTS key	Verificar si existe clave
EXPIRE key seconds	Establecer expiración
TTL key	Obtener TTL restante
KEYS pattern	Encontrar claves (usar SCAN en prod)
FLUSHDB	Eliminar todas las claves
INFO	Información del servidor

Estructuras de datos:

# List
LPUSH mylist "a" "b" "c"
LRANGE mylist 0 -1

# Set
SADD myset "a" "b" "c"
SMEMBERS myset

# Hash
HSET user:1 name "Alice" age 30
HGETALL user:1

# Sorted Set
ZADD leaderboard 100 "player1" 200 "player2"
ZRANGE leaderboard 0 -1 WITHSCORES

Gotchas

Connection refused

# Check if Redis is running
redis-cli ping  # Should return PONG

# Check service status
sudo systemctl status redis

# Check if binding to localhost only
# In redis.conf: bind 127.0.0.1

NOAUTH Authentication required

# Connect with password
redis-cli -a yourpassword

# Or after connecting
AUTH yourpassword

# Set password in redis.conf
requirepass yourpassword

Problemas de memoria

# Check memory usage
redis-cli INFO memory

# Set max memory
# redis.conf: maxmemory 256mb
# redis.conf: maxmemory-policy allkeys-lru

No usar KEYS en producción

# KEYS blocks the server - use SCAN instead
SCAN 0 MATCH "user:*" COUNT 100

Next Steps

• Redis Official Docs
• Redis University
• Redis Insight GUI
• Upstash (Serverless Redis)