This chapter is all about squeezing the most performance possible out of WordPress through optimal server configuration, caching, and clever programming.
WordPress often gets knocked for not scaling as well as other PHP frameworks or other programming languages. The idea that WordPress doesn’t work at scale mostly comes from the fact that WordPress has traditionally been used to run small blogs on shared hosting accounts. Decisions are made by the WordPress core team (including supporting deprecated functionality and older versions of PHP and MySQL) to make sure that WordPress will boot up easily on as many hosting setups as possible, including under-powered shared hosting accounts.
So there are a lot of really slow WordPress sites out in the wild that help to give the impression that WordPress itself is slow. However, WordPress is pretty darn fast on the right setup and can be scaled using the same techniques any PHP/MySQL-based app can use. We will cover many of those techniques in this chapter, introducing you to a number of tools and concepts that can be applied to your own WordPress apps.
In this chapter, and throughout this book, we’ll throw around terms like “optimization” and “scaling.” It’s important to understand exactly what we mean by these terms.
Optimization generally refers to getting your app and scripts to run as fast as possible. In some cases, we will be optimizing for memory use or something other than speed. But ...