Sujal Magar 
1. Introduction
Redis (Remote Dictionary Server) is an in-memory key-value data store used as a database, cache, and message broker.
Data is stored in RAM, making Redis extremely fast.
2. Key Features
- In-memory storage
- Persistence options
- Pub/Sub messaging
- Data structures support
- High performance
3. Data Structures
- Strings
r.set("name", "Alice")- Hashes
r.hset("user:1", mapping={"name": "Alice"})- Lists
r.rpush("tasks", "task1")- Sets
r.sadd("tags", "db")- Sorted Sets
Used for leaderboards.
4. Persistence
Two methods:
- RDB snapshots
- AOF (Append Only File)
5. Expiration (TTL)
r.set("temp", "value", ex=10)6. Pub/Sub
Messaging system.
Publish:
r.publish("channel", "hello")Subscribe via listeners.
7. Transactions
pipe = r.pipeline()
pipe.set("a", 1)
pipe.set("b", 2)
pipe.execute()8. Caching Patterns
- Cache-aside
- Write-through
- Write-behind
9. Use Cases
- Session storage
- Caching queries
- Real-time analytics
- Leaderboards
- Queues
10. Advantages
- Ultra fast
- Lightweight
- Rich data structures
11. Limitations
- RAM dependent
- Limited complex queries