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Introducing Redis

Welcome to the course! In this lesson, you'll get an overview of Redis, understand its core motivations, and set up your environment so you're ready for hands-on learning.

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Whether you're new to databases or just new to Redis, this lesson will ensure you start with a solid foundation.

A Brief History of Redis​

Redis was created in 2009 by Salvatore Sanfilippo (also known as antirez) to address the performance limitations of traditional databases when dealing with real-time web applications. Originally designed to support a startup project that needed fast log aggregation and real-time analytics, Redis quickly evolved into a full-featured data store.

Since then, it has become one of the most widely used NoSQL solutions in the world and is maintained by a vibrant open-source community, with commercial support available via Redis Inc.

What is Redis?​

Redis (REmote DIctionary Server) is a blazing-fast, open-source, in-memory data store that can be used as a:

  • Database
  • Cache
  • Message broker

It supports key-value pairs and a wide range of data structures like:

  • Strings
  • Hashes
  • Lists
  • Sets
  • Sorted Sets (ZSets)
  • Bitmaps and more...

Why Redis Was Needed​

Before Redis, most applications relied heavily on relational databases like MySQL or PostgreSQL for everything—including storing session data, caching, pub/sub systems, and real-time analytics. However, these databases were not designed for ultra-fast operations or high-throughput tasks.

Redis was introduced to solve this problem by:

  • Providing in-memory data access for faster performance
  • Supporting non-relational data structures natively
  • Offering simple and efficient commands for developers
  • Reducing the complexity of building fast, real-time applications

Redis filled the gap between high-latency relational databases and the need for instant access to structured or semi-structured data.

Key Features of Redis​

  1. In-memory Storage: Redis keeps all data in memory for blazing-fast access and sub-millisecond latency. Can read/write upto 100K transactions per second.

  2. Versatile Data Structures: Redis supports multiple types of data—like strings, lists, sets, and hashes—giving you flexibility that traditional key-value stores lack.

  3. Persistence Options: Use RDB snapshots or Append Only File (AOF) logging to persist data to disk.

  4. Replication and Clustering: Redis supports replication (master-replica) and clustering for high availability and horizontal scaling.

  5. Lightweight and Fast: Redis is written in C Language and is extremely lightweight and fast—ideal for low-latency apps.

Why Use Redis? Real-World Use Cases​

Here are some battle-tested use cases from companies like Twitter, GitHub, and Stack Overflow:

  • Caching: Reduce backend load and accelerate responses by caching frequently accessed data.
  • Session Store: Manage user session data in scalable web apps.
  • Leaderboards: Real-time scoring with sorted sets (e.g., gaming platforms).
  • Pub/Sub Systems: Build real-time notification or chat systems.
  • Task Queues: Simple producer-consumer queues without external tooling.
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Want to see it in action? Try using redis-cli to SET and GET keys after installing Redis.