Redis

Open-source, in-memory data structure store.

Connecting to Redis

COMMAND	DESCRIPTION
redis-cli	Connect to local Redis
redis-cli -h host -p port	Connect to remote Redis
redis-cli -a password	Connect with password
redis-cli -u redis://user:password@host:port	Connect with URL
exit or quit	Exit Redis CLI

Key Operations

COMMAND	DESCRIPTION
SET key value	Set key-value pair
GET key	Get value by key
DEL key	Delete key
EXISTS key	Check if key exists
EXPIRE key seconds	Set expiration time
TTL key	Get time to live
EXPIREAT key timestamp	Set expiration at timestamp
PERSIST key	Remove expiration
RENAME oldkey newkey	Rename key
TYPE key	Get data type of key
KEYS pattern	Find keys by pattern
SCAN cursor MATCH pattern COUNT count	Iterate keys

Strings

COMMAND	DESCRIPTION
SET key value	Set string value
GET key	Get string value
GETSET key value	Get and set value
MGET key1 key2 ...	Get multiple values
MSET key1 val1 key2 val2	Set multiple values
INCR key	Increment by 1
INCRBY key amount	Increment by amount
DECR key	Decrement by 1
DECRBY key amount	Decrement by amount
APPEND key value	Append to string
STRLEN key	Get string length
SETRANGE key offset value	Set substring
GETRANGE key start end	Get substring

Hashes

COMMAND	DESCRIPTION
HSET key field value	Set hash field
HGET key field	Get hash field
HMSET key f1 v1 f2 v2	Set multiple fields
HMGET key f1 f2	Get multiple fields
HGETALL key	Get all fields and values
HDEL key field	Delete field
HEXISTS key field	Check if field exists
HKEYS key	Get all fields
HVALS key	Get all values
HLEN key	Get number of fields
HINCRBY key field amount	Increment field by amount

Lists

COMMAND	DESCRIPTION
LPUSH key value1 value2	Push to left
RPUSH key value1 value2	Push to right
LPOP key	Pop from left
RPOP key	Pop from right
LRANGE key start stop	Get range
LLEN key	Get list length
LINDEX key index	Get by index
LSET key index value	Set by index
`LINSERT key BEFORE	AFTER pivot value`
LREM key count value	Remove elements
LTRIM key start stop	Trim list

Sets

COMMAND	DESCRIPTION
SADD key member1 member2	Add members
SREM key member	Remove member
SMEMBERS key	Get all members
SISMEMBER key member	Check if member exists
SCARD key	Get set size
SPOP key	Get and remove random member
SRANDMEMBER key count	Get random members
SINTER key1 key2	Intersection
SUNION key1 key2	Union
SDIFF key1 key2	Difference
SMOVE source destination member	Move member

Sorted Sets

COMMAND	DESCRIPTION
ZADD key score1 member1 score2 member2	Add members with scores
ZREM key member	Remove member
ZSCORE key member	Get score
ZRANGE key start stop	Get range by rank
ZRANGE key start stop WITHSCORES	Get range with scores
ZREVRANGE key start stop	Get range reversed
ZRANK key member	Get rank
ZREVRANK key member	Get reverse rank
ZCOUNT key min max	Count members in score range
ZRANGEBYSCORE key min max	Get by score range
ZINCRBY key increment member	Increment score
ZCARD key	Get number of members
ZREM key member	Remove member

Bitmaps

COMMAND	DESCRIPTION
SETBIT key offset value	Set bit at offset
GETBIT key offset	Get bit at offset
BITCOUNT key	Count set bits
BITOP AND dest key1 key2	Bitwise operations
BITPOS key bit	Find first bit

HyperLogLog

COMMAND	DESCRIPTION
PFADD key element1 element2	Add elements
PFCOUNT key	Count unique elements
PFMERGE dest key1 key2	Merge HyperLogLogs

Transactions

# Start transaction
MULTI

# Queue commands
SET key1 value1
SET key2 value2

# Execute transaction
EXEC

# Discard transaction
DISCARD

Pub/Sub

Publishing

# Publish message
PUBLISH channel "message"

Subscribing

# Subscribe to channel
SUBSCRIBE channel1 channel2

# Unsubscribe
UNSUBSCRIBE channel

# Pattern subscribe
PSUBSCRIBE news.*

Server Operations

COMMAND	DESCRIPTION
DBSIZE	Get number of keys in database
FLUSHDB	Delete all keys in current database
FLUSHALL	Delete all keys in all databases
SAVE	Save to disk
BGSAVE	Save to disk in background
LASTSAVE	Get last save timestamp
SHUTDOWN	Shutdown server
INFO	Get server info
CLIENT LIST	List connected clients
CLIENT KILL ip:port	Kill client connection

Configuration

COMMAND	DESCRIPTION
CONFIG GET parameter	Get configuration
CONFIG SET parameter value	Set configuration
CONFIG RESETSTAT	Reset statistics
CONFIG REWRITE	Rewrite config file

Useful Queries

Get all keys

KEYS *

Get keys by pattern

KEYS user:*

Get Redis info

INFO

INFO memory
INFO replication
INFO stats

Monitor commands

MONITOR

Scan large datasets

SCAN 0 MATCH user:* COUNT 100

Get memory usage

MEMORY USAGE key

Persistence

RDB (Snapshot)

# Enable RDB
CONFIG SET save "900 1 300 10 60 10000"

# Force save
SAVE
BGSAVE

AOF (Append Only File)

# Enable AOF
CONFIG SET appendonly yes

# Rewrite AOF
BGREWRITEAOF

Cluster

COMMAND	DESCRIPTION
CLUSTER NODES	List cluster nodes
CLUSTER INFO	Get cluster info
CLUSTER MEET ip port	Meet a node
CLUSTER ADDSLOTS slot1 slot2	Add slots to node
CLUSTER REPLICATE node_id	Replicate node
CLUSTER FAILOVER	Manual failover

Lua Scripting

# Execute Lua script
EVAL "return redis.call('SET', KEYS[1], ARGV[1])" 1 key value

# Load and execute script
SCRIPT LOAD "return redis.call('GET', KEYS[1])"
EVALSHA <sha> 1 key

Best Practices

• Use appropriate data types for your use case
• Set expiration times to prevent memory bloat
• Use pipelining for multiple commands
• Use transactions for atomic operations
• Monitor memory usage with INFO memory
• Use connection pooling in applications
• Regularly backup Redis data
• Use Redis Cluster for high availability
• Use appropriate eviction policies
• Monitor slow queries with SLOWLOG
• Use Redis Sentinel for automatic failover
• Compress large values stored in Redis

TIP

Use SCAN instead of KEYS for large datasets to avoid blocking the server.