High Performance MySQL, 3rd Edition

Chapter 11. Scaling MySQL

This chapter shows you how to build MySQL-based applications that can grow very large while remaining fast, efficient, and economical.

Which scalability advice is relevant to applications that can fit on a single server or a handful of servers? Most people will never maintain systems at an extremely large scale, and the tactics used at very large and popular companies shouldn’t always be emulated. We’ll try to cover a range of strategies in this chapter. We’ve built or helped build many applications, ranging from those that use a single server or a handful of servers to those that use thousands. Choosing the appropriate strategy for your application is often the key to saving money and time that can be invested elsewhere.

MySQL has been criticized for being hard to scale, and sometimes that’s true, but usually you can make MySQL scale well if you choose the right architecture and implement it well. Scalability is not always a well-understood topic, however, so we’ll begin by clearing up the confusion.

What Is Scalability?

People often use terms such as “scalability,” “high availability,” and “performance” as synonyms in casual conversation, but they’re completely different. As we explained in Chapter 3, we define performance as response time. Scalability can be defined precisely too; we’ll explore that more fully in a moment, but in a nutshell it’s the system’s ability to deliver equal bang for the buck as you add resources to perform more work. Poorly scalable ...