WordPress® All-in-One For Dummies®

Using a Caching System for Speed and Performance

A good way to improve the speed of your Web site is through caching different types of content. Caching content means to store it transparently so that it can be used for future loads of your Web site. A good caching system for your Web site collects all the Web pages on your site and copies, stores, and delivers the files to visitors of your Web site. This significantly reduces the server load because without it, WordPress creates pages on your Web site dynamically — each time a visitor loads your Web site, calls are made to the database and code is complied and executed each time to create the page in her browser. If you use a good caching program, those files are already built and displayed, so your Web server doesn't need to rebuild those pages each time.

The following are the different types of caching that can improve your site performance:

• Page: Builds and stores (in your Web server memory) all the pages on your Web site. Page caches generally have an expiration date. In case you update content on your Web pages, the cache will eventually rebuild itself to capture changes you make.
• Database: Reduces Web server overhead by storing and remembering database tables and queries made by WordPress.
• Browser: Stores Web pages on the visitor's local storage so when she revisits your site, her browser displays the page from her hard drive memory, instead of rebuilding it and calling it from your server. Browser caches have an expiration ...