Redis - Zequel

Overview

Redis is an in-memory key-value data store known for its blazing-fast performance. Zequel provides full support for Redis through the ioredis driver (v5.9.2).

Supported Versions

Redis 5.x
Redis 6.x
Redis 7.x
Redis Stack
Redis Cloud

Connection

Basic Connection

Host: localhost
Port: 6379
Database: 0 (0-15)
Password: (optional)

Connection Options

Redis has 16 logical databases (0-15):

Database: db0, db1, db2, ... db15

Authentication

Redis 6+ supports usernames:

{
  host: 'localhost',
  port: 6379,
  username: 'default',  // Redis 6+
  password: 'your_password'
}

SSL/TLS Connection

Connect to Redis with TLS:

{
  host: 'redis.example.com',
  port: 6380,
  ssl: true,
  sslConfig: {
    rejectUnauthorized: true,
    ca: fs.readFileSync('ca.pem')
  }
}

Redis Commands

Zequel supports all Redis commands through the query editor:

String Operations

SET mykey "Hello World"
GET mykey
INCR counter
DECR counter
APPEND mykey " - Appended"
SETEX session:123 3600 "user_data"  # Expire in 1 hour

Hash Operations

HSET user:1 name "Alice" age 30 email "[email protected]"
HGET user:1 name
HGETALL user:1
HINCRBY user:1 age 1
HDEL user:1 email

List Operations

LPUSH tasks "task1" "task2" "task3"
RPUSH tasks "task4"
LRANGE tasks 0 -1
LPOP tasks
RPOP tasks
LLEN tasks

Set Operations

SADD tags "redis" "database" "cache"
SMEMBERS tags
SISMEMBER tags "redis"
SREM tags "cache"
SCARD tags

Sorted Set Operations

ZADD leaderboard 100 "player1" 200 "player2" 150 "player3"
ZRANGE leaderboard 0 -1 WITHSCORES
ZRANK leaderboard "player1"
ZINCRBY leaderboard 10 "player1"
ZREVRANGE leaderboard 0 2  # Top 3

Key Management

KEYS *
KEYS user:*
EXISTS mykey
DEL mykey
EXPIRE mykey 60
TTL mykey
PERSIST mykey  # Remove expiration
TYPE mykey

Redis Data Structures

Simple key-value pairs

SET name "Alice"
GET name

Max size: 512 MB

Field-value pairs (like objects)

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

Max fields: 2^32 - 1

Ordered collections (like arrays)

LPUSH queue "task1" "task2"
RPOP queue

Max items: 2^32 - 1

Unordered unique values

SADD tags "redis" "cache"
SMEMBERS tags

Max members: 2^32 - 1

Ordered by score

ZADD scores 100 "Alice" 95 "Bob"
ZRANGE scores 0 -1

Max members: 2^32 - 1

Append-only log (Redis 5+)

XADD events * user alice action login
XRANGE events - +

Features

Databases

Redis has 16 logical databases (db0 - db15):

SELECT 1    # Switch to db1
DBSIZE      # Number of keys in current database
FLUSHDB     # Delete all keys in current database
FLUSHALL    # Delete all keys in all databases

Key Patterns

Zequel groups keys by prefix for easier navigation:

user:* - All user-related keys
session:* - All session keys
cache:* - All cache keys

Expiration (TTL)

Set expiration times on keys:

SET cache:page "<html>..." EX 300     # Expire in 300 seconds
EXPIRE cache:page 300                 # Set expiration
TTL cache:page                        # Check remaining time
PERSIST cache:page                    # Remove expiration

Pub/Sub

Publish and subscribe to channels:

# Terminal 1 - Subscribe
SUBSCRIBE notifications

# Terminal 2 - Publish
PUBLISH notifications "Hello, subscribers!"

Transactions

Atomic execution of multiple commands:

MULTI
SET key1 "value1"
SET key2 "value2"
INCR counter
EXEC

Lua Scripting

Execute custom Lua scripts atomically:

EVAL "return redis.call('SET', KEYS[1], ARGV[1])" 1 mykey myvalue

Redis-Specific Features

Persistence

Redis offers two persistence modes:

RDB: Periodic snapshots
AOF: Append-only file (every write)

# Check persistence config
CONFIG GET save
CONFIG GET appendonly

# Manual snapshot
SAVE
BGSAVE  # Background save

Memory Management

# Memory info
INFO memory
MEMORY USAGE mykey

# Eviction policies
CONFIG GET maxmemory-policy
# Options: noeviction, allkeys-lru, volatile-lru, etc.

Replication

# On replica
REPLICOF master-host master-port

# Check replication status
INFO replication

Cluster

Redis Cluster for horizontal scaling:

CLUSTER INFO
CLUSTER NODES

ACL (Access Control Lists - Redis 6+)

Manage users and permissions:

ACL LIST
ACL SETUSER alice on >password ~* &* +@all
ACL DELUSER alice

Zequel provides UI for user management on Redis 6+.

Advanced Commands

Scanning Keys

Zequel uses SCAN for non-blocking key iteration:

SCAN 0 MATCH user:* COUNT 100

Zequel automatically uses SCAN instead of KEYS to avoid blocking the server on large datasets.

Geo Commands (Geospatial)

GEOADD locations 13.361389 38.115556 "Palermo"
GEOADD locations 15.087269 37.502669 "Catania"
GEODIST locations "Palermo" "Catania" km
GEORADIUS locations 15 37 200 km

HyperLogLog (Cardinality Estimation)

PFADD visitors "user1" "user2" "user3"
PFCOUNT visitors  # Approximate count

Bitmap Operations

SETBIT online:2024-01-01 123 1  # User 123 was online
GETBIT online:2024-01-01 123
BITCOUNT online:2024-01-01

Performance & Monitoring

Info Command

INFO
INFO server
INFO memory
INFO stats
INFO replication

Slow Log

SLOWLOG GET 10  # Get last 10 slow commands
SLOWLOG RESET

Monitor

MONITOR  # Real-time command stream (use carefully!)

Benchmarking

# From terminal
redis-benchmark -h localhost -p 6379 -c 50 -n 10000

Limitations

Redis is an in-memory store with some constraints:

Memory-bound: All data must fit in RAM
No complex queries: No SQL-like joins or aggregations
No foreign keys: Relationships managed in application code
No transactions across databases: MULTI/EXEC works within one database
Single-threaded (mostly): One command at a time per core

Use Cases

Ideal For:

✅ Caching (session storage, API responses) ✅ Real-time analytics (counters, metrics) ✅ Leaderboards (sorted sets) ✅ Pub/Sub messaging ✅ Rate limiting ✅ Job queues ✅ Geospatial data

Not Ideal For:

❌ Primary data storage (use with persistence) ❌ Complex queries and joins ❌ Large datasets that don’t fit in RAM ❌ Full-text search (use RediSearch module)

Best Practices

Use key naming conventions

user:1:profile
user:1:sessions
cache:page:home

Set expiration on cache keys
```
SETEX cache:api:users 3600 "[...]"
```

Use pipelining for bulk operations

const pipeline = redis.pipeline();
pipeline.set('key1', 'value1');
pipeline.set('key2', 'value2');
await pipeline.exec();

Monitor memory usage
```
INFO memory
MEMORY DOCTOR
```
Use appropriate data structures
- Counters: Strings with INCR
- User sessions: Hashes
- Queues: Lists
- Tags: Sets
- Leaderboards: Sorted Sets

Enable persistence for important data

# redis.conf
save 900 1      # Save after 900s if 1 key changed
appendonly yes  # Enable AOF

Docker Development

Zequel includes Redis in Docker Compose:

services:
  redis:
    image: redis:7-alpine
    ports:
      - "6379:6379"
    command: redis-server --requirepass redis

Supported Databases

​Overview

​Supported Versions

​Connection

​Basic Connection

​Connection Options

​Authentication

​SSL/TLS Connection

​Redis Commands

​String Operations

​Hash Operations

​List Operations

​Set Operations

​Sorted Set Operations

​Key Management

​Redis Data Structures

​Features

​Databases

​Key Patterns

​Expiration (TTL)

​Pub/Sub

​Transactions

​Lua Scripting

​Redis-Specific Features

​Persistence

​Memory Management

​Replication

​Cluster

​ACL (Access Control Lists - Redis 6+)

​Advanced Commands

​Scanning Keys

​Geo Commands (Geospatial)

​HyperLogLog (Cardinality Estimation)

​Bitmap Operations

​Performance & Monitoring

​Info Command

​Slow Log

​Monitor

​Benchmarking

​Limitations

​Use Cases

​Ideal For:

​Not Ideal For:

​Best Practices

​Docker Development

​Additional Resources

Build docs developers (and LLMs) love

Overview

Supported Versions

Connection

Basic Connection

Connection Options

Authentication

SSL/TLS Connection

Redis Commands

String Operations

Hash Operations

List Operations

Set Operations

Sorted Set Operations

Key Management

Redis Data Structures

Features

Databases

Key Patterns

Expiration (TTL)

Pub/Sub

Transactions

Lua Scripting

Redis-Specific Features

Persistence

Memory Management

Replication

Cluster

ACL (Access Control Lists - Redis 6+)

Advanced Commands

Scanning Keys

Geo Commands (Geospatial)

HyperLogLog (Cardinality Estimation)

Bitmap Operations

Performance & Monitoring

Info Command

Slow Log

Monitor

Benchmarking

Limitations

Use Cases

Ideal For:

Not Ideal For:

Best Practices

Docker Development

Additional Resources