SQLite Object Cache

A persistent object cache helps your site perform well. This one uses the widely available SQLite3 extension to php. Many hosting services offer it. If your hosting service does not provide memcached or redis, you may be able to use this plugin instead and get the benefit of object caching.

Caches are ubiquitous in computing, and WordPress has its own caching subsystem. Caches contain short-term copies of the results of expensive database lookups or computations, and allow software to use the copy rather than repeating the expensive operation. This plugin (like other object-caching plugins) extends WordPress’s caching subsystem to save those short-term copies from page view to page view. WordPress’s cache happens to be a memoization cache.

Without a persistent object cache, every WordPress page view must use your MariaDB or MySQL database server to retrieve everything about your site. When a user requests a page, WordPress starts from scratch and loads everything it needs from your database server. Only then can it deliver content to your user. With a persistent object cache, WordPress immediately loads much of the information it needs. This lightens the load on your database server and delivers content to your users faster.

Thanks to Till Krüss. His Redis Object Cache plugin serves as a model for this one. And thanks to Ari Stathopoulos and Jonny Harris for reviewing this. (All defects are, of course, entirely the author’s responsibility.)

And thanks to Jetbrains for the use of their software development tools, especially PhpStorm. It’s hard to imagine how a plugin like this one could be developed without PhpStorm’s tools for exploring epic code bases like WordPress’s.