Redis – Introduction
1. What is Redis?
- Redis stands for Remote Dictionary Server.
- It is an open-source, in-memory data structure store.
Used as:
- Database
- Cache
- Message broker
- Known for high speed and low latency operations.
2. Key Features
- In-memory: Stores data in RAM → extremely fast access.
- Key-Value Store: Works with keys and values.
- Data Structures: Supports strings, lists, sets, sorted sets, hashes, streams, bitmaps, and hyperloglogs.
Persistence:
- RDB (Snapshotting) – Saves data at intervals.
- AOF (Append Only File) – Logs every write operation.
- Replication: Master-slave replication for high availability.
- Pub/Sub Messaging: Built-in publish/subscribe system.
- Transactions: Allows execution of multiple commands as a single isolated operation.
- Cluster Support: Distributed setup for scalability.
3. Why Use Redis?
- Speed: Can handle millions of requests per second.
- Scalability: Supports sharding and clustering.
- Versatility: Can be used for caching, session management, queues, leaderboards, real-time analytics, etc.
- Lightweight: Minimal latency compared to traditional databases.
4. Common Use Cases
- Caching: Store frequently accessed data to reduce database load.
- Session Store: Manage user sessions in web applications.
- Message Queues: Handle background jobs and events.
- Real-time Analytics: Process counters, leaderboards, tracking.
- Pub/Sub Applications: Chat systems, notification services.
5. Advantages
- Extremely fast due to in-memory design.
- Supports rich data structures.
- Built-in replication and persistence.
- Flexible deployment options (on-premise, cloud).
- Open-source with a large community.
6. Limitations
- Data is stored in memory → can be costly for very large datasets.
- Limited to single-threaded command execution (though highly optimized).
- Requires careful configuration to avoid data loss in case of crashes.
7. Getting Started
- Installation: Available for Linux, macOS, Windows (via WSL or Docker).
Basic Commands:
SET key value GET key DEL key INCR counter LPUSH list value LRANGE list 0 -1- Clients: Available for many languages – Python, Java, Node.js, Go, PHP, etc.
Tags:
Redis