Redis Cheatsheet

Redis Installation & Setup

Docker: docker run redis

Quickest way to get Redis running locally.

# Run Redis in Docker
docker run --name my-redis -p 6379:6379 -d redis
# Connect to Redis CLI
docker exec -it my-redis redis-cli
# Run with persistent storage
docker run --name redis-persistent -p 6379:6379 -v redis-data:/data -d redis

Linux: sudo apt install redis

Install Redis server on Ubuntu/Debian systems.

# Install Redis
sudo apt update
sudo apt install redis-server
# Start Redis service
sudo systemctl start redis-server
# Enable auto-start on boot
sudo systemctl enable redis-server
# Check status
sudo systemctl status redis

Connect & Test: redis-cli

Connect to Redis server and verify installation.

# Connect to local Redis
redis-cli
# Test connection
redis-cli PING
# Connect to remote Redis
redis-cli -h hostname -p 6379 -a password
# Execute single command
redis-cli SET mykey "Hello Redis"

Basic String Operations

Set & Get: SET / GET

Store simple values (text, numbers, JSON, etc.).

# Set a key-value pair
SET mykey "Hello World"
# Get value by key
GET mykey
# Set with expiration (in seconds)
SET session:123 "user_data" EX 3600
# Set only if key doesn't exist
SET mykey "new_value" NX

String Manipulation: APPEND / STRLEN

Modify and inspect string values.

# Append to existing string
APPEND mykey " - Welcome!"
# Get string length
STRLEN mykey
# Get substring
GETRANGE mykey 0 4
# Set substring
SETRANGE mykey 6 "Redis"

Number Operations: INCR / DECR

Increment or decrement integer values stored in Redis.

# Increment by 1
INCR counter
# Decrement by 1
DECR counter
# Increment by specific amount
INCRBY counter 5
# Increment float
INCRBYFLOAT price 0.1

Multiple Operations: MSET / MGET

Work with multiple key-value pairs efficiently.

# Set multiple keys at once
MSET key1 "value1" key2 "value2" key3 "value3"
# Get multiple values
MGET key1 key2 key3
# Set multiple only if none exist
MSETNX key1 "val1" key2 "val2"

List Operations

Lists are ordered sequences of strings, useful as queues or stacks.

Add Elements: LPUSH / RPUSH

Add elements to the left (head) or right (tail) of a list.

# Add to head (left)
LPUSH mylist "first"
# Add to tail (right)
RPUSH mylist "last"
# Add multiple elements
LPUSH mylist "item1" "item2" "item3"

Remove Elements: LPOP / RPOP

Remove and return elements from list ends.

# Remove from head
LPOP mylist
# Remove from tail
RPOP mylist
# Blocking pop (wait for element)
BLPOP mylist 10

Access Elements: LRANGE / LINDEX

Retrieve elements or ranges from lists.

# Get entire list
LRANGE mylist 0 -1
# Get first 3 elements
LRANGE mylist 0 2
# Get specific element by index
LINDEX mylist 0
# Get list length
LLEN mylist

List Utilities: LSET / LTRIM

Modify list contents and structure.

# Set element at index
LSET mylist 0 "new_value"
# Trim list to range
LTRIM mylist 0 99
# Find position of element
LPOS mylist "search_value"

Set Operations

Sets are collections of unique, unordered string elements.

Basic Set Operations: SADD / SMEMBERS

Add unique elements to sets and retrieve all members.

# Add elements to set
SADD myset "apple" "banana" "cherry"
# Get all set members
SMEMBERS myset
# Check if element exists
SISMEMBER myset "apple"

Set Modifications: SREM / SPOP

Remove elements from sets in different ways.

# Remove specific elements
SREM myset "banana"
# Remove and return random element
SPOP myset
# Get random element without removing
SRANDMEMBER myset

Set Operations: SINTER / SUNION

Perform mathematical set operations.

# Intersection of sets
SINTER set1 set2
# Union of sets
SUNION set1 set2
# Difference of sets
SDIFF set1 set2
# Store result in new set
SINTERSTORE result set1 set2

Set Utilities: SMOVE / SSCAN

Advanced set manipulation and scanning.

# Move element between sets
SMOVE source_set dest_set "element"
# Scan set incrementally
SSCAN myset 0 MATCH "a*" COUNT 10

Hash Operations

Hashes store field-value pairs, like mini JSON objects or dictionaries.

Basic Hash Operations: HSET / HGET

Set and retrieve individual hash fields.

# Set hash field
HSET user:123 name "John Doe" age 30
# Get hash field
HGET user:123 name
# Set multiple fields
HMSET user:123 email "john@example.com" city "NYC"
# Get multiple fields
HMGET user:123 name age email

Hash Inspection: HKEYS / HVALS

Examine hash structure and contents.

# Get all field names
HKEYS user:123
# Get all values
HVALS user:123
# Get all fields and values
HGETALL user:123
# Get number of fields
HLEN user:123

Hash Utilities: HEXISTS / HDEL

Check existence and remove hash fields.

# Check if field exists
HEXISTS user:123 email
# Delete fields
HDEL user:123 age city
# Increment hash field
HINCRBY user:123 age 1
# Increment by float
HINCRBYFLOAT user:123 balance 10.50

Hash Scanning: HSCAN

Iterate through large hashes incrementally.

# Scan hash fields
HSCAN user:123 0
# Scan with pattern matching
HSCAN user:123 0 MATCH "addr*" COUNT 10

Sorted Set Operations

Sorted sets combine uniqueness of sets with ordering based on scores.

Basic Operations: ZADD / ZRANGE

Add scored members and retrieve ranges.

# Add members with scores
ZADD leaderboard 100 "player1" 200 "player2"
# Get members by rank (0-based)
ZRANGE leaderboard 0 -1
# Get with scores
ZRANGE leaderboard 0 -1 WITHSCORES
# Get by score range
ZRANGEBYSCORE leaderboard 100 200

Sorted Set Info: ZCARD / ZSCORE

Get information about sorted set members.

# Get set size
ZCARD leaderboard
# Get member score
ZSCORE leaderboard "player1"
# Get member rank
ZRANK leaderboard "player1"
# Count members in score range
ZCOUNT leaderboard 100 200

Modifications: ZREM / ZINCRBY

Remove members and modify scores.

# Remove members
ZREM leaderboard "player1"
# Increment member score
ZINCRBY leaderboard 10 "player2"
# Remove by rank
ZREMRANGEBYRANK leaderboard 0 2
# Remove by score
ZREMRANGEBYSCORE leaderboard 0 100

Advanced: ZUNIONSTORE / ZINTERSTORE

Combine multiple sorted sets.

# Union of sorted sets
ZUNIONSTORE result 2 set1 set2
# Intersection with weights
ZINTERSTORE result 2 set1 set2 WEIGHTS 1 2
# With aggregation function
ZUNIONSTORE result 2 set1 set2 AGGREGATE MAX

Key Management

Key Inspection: KEYS / EXISTS

Find keys using patterns and check existence.

# Get all keys (use carefully in production)
KEYS *
# Keys with pattern
KEYS user:*
# Keys ending with pattern
KEYS *:profile
# Single character wildcard
KEYS order:?
# Check if key exists
EXISTS mykey

Key Information: TYPE / TTL

Get key metadata and expiration information.

# Get key data type
TYPE mykey
# Get time to live (seconds)
TTL mykey
# Get TTL in milliseconds
PTTL mykey
# Remove expiration
PERSIST mykey

Key Operations: RENAME / DEL

Rename, delete, and move keys.

# Rename key
RENAME oldkey newkey
# Rename only if new key doesn't exist
RENAMENX oldkey newkey
# Delete keys
DEL key1 key2 key3
# Move key to different database
MOVE mykey 1

Expiration: EXPIRE / EXPIREAT

Set key expiration times.

# Set expiration in seconds
EXPIRE mykey 3600
# Set expiration at specific timestamp
EXPIREAT mykey 1609459200
# Set expiration in milliseconds
PEXPIRE mykey 60000

Database Management

Database Selection: SELECT / FLUSHDB

Manage multiple databases within Redis.

# Select database (0-15 by default)
SELECT 0
# Clear current database
FLUSHDB
# Clear all databases
FLUSHALL
# Get current database size
DBSIZE

Server Info: INFO / PING

Get server statistics and test connectivity.

# Test server connection
PING
# Get server information
INFO
# Get specific info section
INFO memory
INFO replication
# Get server time
TIME

Persistence: SAVE / BGSAVE

Control Redis data persistence and backups.

# Synchronous save (blocks server)
SAVE
# Background save (non-blocking)
BGSAVE
# Get last save time
LASTSAVE
# Rewrite AOF file
BGREWRITEAOF

Configuration: CONFIG GET / CONFIG SET

View and modify Redis configuration.

# Get all configuration
CONFIG GET *
# Get specific config
CONFIG GET maxmemory
# Set configuration
CONFIG SET timeout 300
# Reset configuration
CONFIG RESETSTAT

Performance Monitoring

Real-time Monitoring: MONITOR / SLOWLOG

Track commands and identify performance bottlenecks.

# Monitor all commands in real-time
MONITOR
# Get slow query log
SLOWLOG GET 10
# Get slow log length
SLOWLOG LEN
# Reset slow log
SLOWLOG RESET

Memory Analysis: MEMORY USAGE / MEMORY STATS

Analyze memory consumption and optimization.

# Get key memory usage
MEMORY USAGE mykey
# Get memory statistics
MEMORY STATS
# Get memory doctor report
MEMORY DOCTOR
# Purge memory
MEMORY PURGE

Client Information: CLIENT LIST

Monitor connected clients and connections.

# List all clients
CLIENT LIST
# Get client info
CLIENT INFO
# Kill client connection
CLIENT KILL ip:port
# Set client name
CLIENT SETNAME "my-app"

Benchmarking: redis-benchmark

Test Redis performance with built-in benchmark tool.

# Basic benchmark
redis-benchmark
# Specific operations
redis-benchmark -t SET,GET -n 100000
# Custom payload size
redis-benchmark -d 1024 -t SET -n 10000

Advanced Features

Transactions: MULTI / EXEC

Execute multiple commands atomically.

# Start transaction
MULTI
SET key1 "value1"
INCR counter
# Execute all commands
EXEC
# Discard transaction
DISCARD
# Watch keys for changes
WATCH mykey

Pub/Sub: PUBLISH / SUBSCRIBE

Implement message passing between clients.

# Subscribe to channel
SUBSCRIBE news sports
# Publish message
PUBLISH news "Breaking: Redis 7.0 released!"
# Pattern subscription
PSUBSCRIBE news:*
# Unsubscribe
UNSUBSCRIBE news

Lua Scripting: EVAL / SCRIPT

Execute custom Lua scripts atomically.

# Execute Lua script
EVAL "return redis.call('SET', 'key', 'value')" 0
# Load script and get SHA
SCRIPT LOAD "return redis.call('GET', KEYS[1])"
# Execute by SHA
EVALSHA sha1 1 mykey
# Check script existence
SCRIPT EXISTS sha1

Streams: XADD / XREAD

Work with Redis streams for log-like data.

# Add entry to stream
XADD mystream * field1 value1 field2 value2
# Read from stream
XREAD STREAMS mystream 0
# Get stream length
XLEN mystream
# Create consumer group
XGROUP CREATE mystream mygroup 0

Data Types Overview

Strings: Most versatile type

Can store text, numbers, JSON, binary data. Max size: 512MB. Use for: caching, counters, flags.

SET user:123:name "John"
GET user:123:name
INCR page:views

Lists: Ordered collections

Linked lists of strings. Use for: queues, stacks, activity feeds, recent items.

LPUSH queue:jobs "job1"
RPOP queue:jobs
LRANGE recent:posts 0 9

Sets: Unique collections

Unordered collections of unique strings. Use for: tags, unique visitors, relationships.

SADD post:123:tags "redis" "database"
SISMEMBER post:123:tags "redis"
SINTER user:123:friends user:456:friends

Redis Configuration Tips

Memory Management

Configure memory limits and eviction policies.

# Set memory limit
CONFIG SET maxmemory 2gb
# Set eviction policy
CONFIG SET maxmemory-policy allkeys-lru
# Check memory usage
INFO memory

Persistence Settings

Configure data durability options.

# Enable AOF
CONFIG SET appendonly yes
# Set save intervals
CONFIG SET save "900 1 300 10 60 10000"
# AOF rewrite settings
CONFIG SET auto-aof-rewrite-percentage 100

Security Settings

Basic security configurations for Redis.

# Set password
CONFIG SET requirepass mypassword
# Authenticate
AUTH mypassword
# Disable dangerous commands
CONFIG SET rename-command FLUSHALL ""
# Set timeout
CONFIG SET timeout 300
# TCP keep alive
CONFIG SET tcp-keepalive 60
# Max clients
CONFIG SET maxclients 10000

Performance Tuning

Optimize Redis for better performance.

# Enable pipelining for multiple commands
# Use connection pooling
# Configure appropriate maxmemory-policy
# Monitor slow queries regularly
# Use appropriate data structures for use cases

Relevant Links

• Database Cheatsheet
• MySQL Cheatsheet
• PostgreSQL Cheatsheet
• MongoDB Cheatsheet
• SQLite Cheatsheet
• Python Cheatsheet
• JavaScript Cheatsheet
• DevOps Cheatsheet