Memcached versus Redis

Compare Memcached and Redis, two widely adopted distributed cache implementations. Analyze their architectural differences, including data structures, persistence capabilities, and the complexity of cluster management. Determine which caching solution best fits specific system requirements, such as read-heavy vs. complex read/write loads.

We'll cover the following...

Introduction
Memcached
- Facebook and Memcached
Redis
- Redis Cluster
- Pipelining in Redis
Memcached vs. Redis
Conclusion

Introduction

This lesson explores two widely used open-source caching frameworks: Memcached and Redis. Both use a client–server architecture and provide sub-millisecond latency.

Memcached

Introduced in 2003, Memcached is a high-performance distributed key-value store. It stores data as string-based key-value pairs. Because it only supports strings, complex objects must be serializedSerialization is the process of translating data into a format that can be transmitted or stored elsewhere. Later, reconstruction or deserialization of the data should be possible. before storage. Memcached uses a shared-nothing architecture. Servers operate independently without synchronization or data sharing. System logic is divided between the client and server: the client performs routing and hashing, while the server manages storage.

This disconnected design allows Memcached to achieve deterministic query speeds of $\text{O(1)}$ and high throughput, serving millions of keys per second on high-end hardware.