redis-best-practices

# Good key naming examples
user:1234:profile
user:1234:sessions
order:5678:items
cache:api:products:list
queue:email:pending
session:abc123def456
rate_limit:api:user:1234

# Simple caching
SET cache:user:1234 '{"name":"John","email":"john@example.com"}' EX 3600
 
# Counters
INCR stats:pageviews:homepage
INCRBY stats:downloads:file123 5
 
# Atomic operations
SETNX lock:resource:456 "owner:abc" EX 30

# Store user profile
HSET user:1234 name "John Doe" email "john@example.com" created_at "2024-01-15"
 
# Get specific fields
HGET user:1234 email
HMGET user:1234 name email
 
# Increment numeric fields
HINCRBY user:1234 login_count 1
 
# Get all fields
HGETALL user:1234

# Message queue
LPUSH queue:emails '{"to":"user@example.com","subject":"Welcome"}'
RPOP queue:emails
 
# Blocking pop for workers
BRPOP queue:emails 30
 
# Recent activity (keep last 100)
LPUSH user:1234:activity "viewed product 567"
LTRIM user:1234:activity 0 99
 
# Get recent items
LRANGE user:1234:activity 0 9

# User tags/interests
SADD user:1234:interests "technology" "music" "travel"
 
# Check membership
SISMEMBER user:1234:interests "music"
 
# Find common interests
SINTER user:1234:interests user:5678:interests
 
# Online users tracking
SADD online:users "user:1234"
SREM online:users "user:1234"
SMEMBERS online:users

# Leaderboard
ZADD leaderboard:game1 1500 "player:123" 2000 "player:456" 1800 "player:789"
 
# Get top 10
ZREVRANGE leaderboard:game1 0 9 WITHSCORES
 
# Get player rank
ZREVRANK leaderboard:game1 "player:123"
 
# Time-based data (score = timestamp)
ZADD events:user:1234 1705329600 "login" 1705330000 "purchase"
 
# Get events in time range
ZRANGEBYSCORE events:user:1234 1705329600 1705333200

# Add events to stream
XADD events:orders * customer_id 1234 product_id 567 amount 99.99
 
# Read from stream
XREAD COUNT 10 STREAMS events:orders 0
 
# Consumer groups
XGROUP CREATE events:orders order-processors $ MKSTREAM
XREADGROUP GROUP order-processors worker1 COUNT 10 STREAMS events:orders >
 
# Acknowledge processed messages
XACK events:orders order-processors 1234567890-0

# Pseudo-code for cache-aside
def get_user(user_id):
    # Try cache first
    cached = redis.get(f"cache:user:{user_id}")
    if cached:
        return json.loads(cached)
 
    # Cache miss - fetch from database
    user = database.get_user(user_id)
 
    # Store in cache with expiration
    redis.setex(f"cache:user:{user_id}", 3600, json.dumps(user))
 
    return user

def update_user(user_id, data):
    # Update database
    database.update_user(user_id, data)
 
    # Update cache
    redis.setex(f"cache:user:{user_id}", 3600, json.dumps(data))

# Delete specific cache
DEL cache:user:1234
 
# Delete by pattern (use with caution in production)
# Use SCAN instead of KEYS for large datasets
SCAN 0 MATCH cache:user:* COUNT 100
 
# Tag-based invalidation using sets
SADD cache:tags:user:1234 "cache:user:1234:profile" "cache:user:1234:orders"
# Invalidate all related caches
SMEMBERS cache:tags:user:1234
# Then delete each key

# Set with expiration
SET cache:data:123 "value" EX 3600
 
# Set expiration on existing key
EXPIRE cache:data:123 3600
 
# Check TTL
TTL cache:data:123
 
# Persist key (remove expiration)
PERSIST cache:data:123

# Check memory usage
INFO memory
 
# Get key memory usage
MEMORY USAGE cache:large:object
 
# Configure max memory policy
CONFIG SET maxmemory 2gb
CONFIG SET maxmemory-policy allkeys-lru

# Transaction block
MULTI
INCR stats:views
LPUSH recent:views "page:123"
EXEC
 
# Watch for optimistic locking
WATCH user:1234:balance
balance = GET user:1234:balance
MULTI
SET user:1234:balance (balance - 100)
EXEC

-- Rate limiting script
local key = KEYS[1]
local limit = tonumber(ARGV[1])
local window = tonumber(ARGV[2])
 
local current = tonumber(redis.call('GET', key) or '0')
 
if current >= limit then
    return 0
end
 
redis.call('INCR', key)
if current == 0 then
    redis.call('EXPIRE', key, window)
end
 
return 1

# Execute Lua script
EVAL "return redis.call('GET', KEYS[1])" 1 mykey

# Publisher
PUBLISH channel:notifications '{"type":"alert","message":"New order"}'
 
# Subscriber
SUBSCRIBE channel:notifications
 
# Pattern subscription
PSUBSCRIBE channel:*

# On replica
REPLICAOF master_host 6379
 
# Check replication status
INFO replication

# Hash tags ensure keys go to same slot
SET {user:1234}:profile "data"
SET {user:1234}:settings "data"

# Manual snapshot
BGSAVE
 
# Configure automatic snapshots
CONFIG SET save "900 1 300 10 60 10000"

# Enable AOF
CONFIG SET appendonly yes
CONFIG SET appendfsync everysec
 
# Rewrite AOF
BGREWRITEAOF

# Set password
CONFIG SET requirepass "your_strong_password"
 
# Authenticate
AUTH your_strong_password
 
# Rename dangerous commands (in redis.conf)
rename-command FLUSHALL ""
rename-command FLUSHDB ""
rename-command KEYS ""

# Server info
INFO
 
# Memory stats
INFO memory
 
# Client connections
CLIENT LIST
 
# Slow log
SLOWLOG GET 10
 
# Monitor commands (debug only)
MONITOR
 
# Key count per database
INFO keyspace

# Python example with connection pool
import redis
 
pool = redis.ConnectionPool(
    host='localhost',
    port=6379,
    max_connections=50,
    socket_timeout=5,
    socket_connect_timeout=5
)
 
redis_client = redis.Redis(connection_pool=pool)

# Pipeline example (pseudo-code)
pipe = redis.pipeline()
pipe.get("key1")
pipe.get("key2")
pipe.set("key3", "value")
results = pipe.execute()