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Redis

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What is Redis?

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Key Features

• Redis 7.0: Latest stable version
• Clustering: High availability with Redis Cluster
• Persistence: RDB and AOF persistence options
• Pub/Sub: Publish-subscribe messaging
• Data Structures: Strings, lists, sets, sorted sets, hashes
• Monitoring: Real-time performance metrics
• Automatic Failover: High availability

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Use Cases

• Caching database queries
• Session storage
• Real-time leaderboards
• Rate limiting
• Message queues
• Pub/sub messaging
• Chat applications

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Getting Started

1. Create a Redis instance from your dashboard
2. Choose plan (Single node or Cluster)
3. Configure persistence options
4. Get connection string and credentials
5. Connect your application

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Connection Examples

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Node.js

const redis = require('redis');

const client = redis.createClient({
  url: process.env.REDIS_URL
});

await client.connect();

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Python

import redis

r = redis.from_url(os.environ['REDIS_URL'])

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Go

import "github.com/redis/go-redis/v9"

rdb := redis.NewClient(&redis.Options{
    Addr: os.Getenv("REDIS_URL"),
})

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Data Structures

• Strings: Simple key-value pairs
• Lists: Ordered collections
• Sets: Unordered unique collections
• Sorted Sets: Ordered unique collections with scores
• Hashes: Field-value maps
• Streams: Log-like data structure

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Clustering

• Redis Cluster: Automatic sharding
• High Availability: Multiple node replicas
• Automatic Failover: Promote replica to primary
• Data Distribution: Distribute keys across nodes

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Persistence

• RDB: Point-in-time snapshots
• AOF: Append-only file for durability
• Hybrid: RDB + AOF for maximum durability
• Backups: Manual and scheduled backups

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Security

• Authentication: Password-based auth
• TLS Encryption: Encrypted connections
• Network Isolation: Private network connectivity
• IP Whitelisting: Restrict access by IP

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Monitoring

• Memory Usage: Used memory and peak memory
• Ops/sec: Operations per second
• Keys: Total key count
• Hits/Misses: Cache hit ratio
• Connected Clients: Active connections

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Common Patterns

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Caching

// Get from cache or database
const cacheKey = `user:${userId}`;
let user = await client.get(cacheKey);

if (!user) {
  user = await db.getUser(userId);
  await client.setEx(cacheKey, 3600, JSON.stringify(user));
}

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Session Storage

// Store session
await client.setEx(`session:${sessionId}`, 3600, JSON.stringify(sessionData));

// Get session
const session = await client.get(`session:${sessionId}`);