SQLite Object Cache vs Next Page Caching

Your website visitors usually jump from page to page, or read your blog posts one after the other. Current caching plugins perform caching on the current page you are on. This plugin caches the next page your visitor will go to. This means your visitors can navigate your website faster. How Does This Work? Next Page Caching implements awesome “next page” caching to your site – this is different from your typical caching plugins like WP Rocket and W3 Total Cache. Instead of only trying to serve the current page faster to your visitors, this plugin lets your browser load parts of the next page while the visitor is busy reading the current page he/she is on. It does this with your help. We ask you two things in every post/page: First is what you think the next webpage your visitor will most likely go to afterwards, and second is a short list of critical files that you think should be loaded first in your page to make the top part of the page become visible quickly. With those two items, the plugin can now preload the important parts of the next page he’ll go to. The plugin also prioritizes the loading of the chosen critical files to ensure that the next page is visible as soon as possible. For example, if you find that a majority of your visitors in your front page check out the pricing page, then pick your pricing page as the “next page”. The visitors who navigate from your front page to your pricing page should see some speed benefits. This is not meant to replace your current caching plugin, but instead, this is meant to be used alongside it. What Caching Does This Do? The plugin prefetches the main HTML of the chosen next page, as well as the critical files specified. Prefetches the first post when viewing a blog list or archive page. Preloads the post’s chosen critical files to prioritize them. Preloads the theme stylesheet so that it gets loaded first. Preloads the featured image of a blog post or page when needed (and if it’s large) so that it shows up faster. Preconnects to the Google Fonts domain for faster font downloading when needed. Important Notice Do not replace your current caching plugin with this one, use this one together with your existing one. This plugin does not predict / analyze where your visitors will go next This plugin only has benefits in Modern Browsers

A persistent object cache helps your site perform well. This one uses the widely available SQLite3 extension, and optionally the igbinary and APCu extensions to php. Many hosting services offer those extensions, and they are easy to install on a server you control. What is this about? It’s about making your site’s web server perform better. An object cache does that by reducing the workload on your MariaDB or MySQL database. This is not a page cache; these persistent objects go into a different kind of cache. These objects aren’t chunks of web pages ready for people to view in their browsers, they are data objects for use by the WordPress software. 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. Who should use this? If your site runs on a single web server machine, and that server provides the SQLite3 and igbinary extensions to php, this plugin will almost certainly make your site work faster. And if that server provides the APCu extension, this plugin uses it too. Some hosting providers offer redis cache servers. If your provider offers redis, it may be a good choice. You can use it via the Redis Object Cache plugin. Sites using redis have one SQL database and another non-SQL storage server: redis. Other hosting providers offer memcached, which has the Memcached Object Cache plugin. And some large multipurpose cache plugins, such as the LiteSpeed Cache, also offer object caching based on one of those cache server software packages. The cache-server approach to object caching comes into its own when you have multiple load-balanced web server machines handling your site. SQLite doesn’t work correctly in a multiple-web-server environment. But, for single-server site configurations, SQLite, possibly assisted by APCu, performs well. And the vast majority of sites are single-server. APCu APCu is an in-memory storage medium. It lets php programs, like WordPress, store data in shared memory so it’s very fast to retrieve when needed. If APCu is available on your host server, you can configure this plugin to use it. It reduces the typical cache lookup time to one-fifth or less of the SQLite lookup time, which is itself a few tens of microseconds. Performance counts, especially on busy web sites. Please look at Installation to learn how to configure this plugin to use APCu. The plugin works fast without it, and faster with it. WP-CLI: Even if APCu is in use, caching with SQLite is necessary when your web site uses WP-CLI, because WP-CLI programs do not have access to the APCu cache. This plugin writes all cached data both to APCu and to SQLite and makes sure the two are synchronized. WP-CLI You can control this plugin via WP-CLI once you activate it. Please type this command into your shell for details. wp help sqlite-object-cache Credits 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. Props to Matt Jones for finding and fixing a bug that appeared on a heavily loaded system. Thanks to Massimo Villa for testing help, and to nickchomey for a comprehensive code review. 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. How can I learn more about making my WordPress site more efficient? We offer several plugins to help with your site’s database efficiency. You can read about them here.