APCu Manager vs SQLite Object Cache

APCu statistics and management right in the WordPress admin dashboard. APCu Manager offers a persistent object cache backend to WordPress: just activate the option in the settings and you will experience a real speed up of your site or network. APCu Manager is a full featured APCu management and analytics reporting tool. It allows you to monitor and optimize APCu operations on your WordPress site or network. APCu Manager works on dedicated or shared servers. It is compatible with all plugins using WordPress object caching. Its main management features are: drop-in replacement for WordPress object caching; individual object deletion; bulk object deletion; objects browsing and inspecting; smart garbage collection; full cache clearing. ⚠️ APCu Manager doesn’t work on PHP clustered environments! APCu Manager is also a full featured analytics reporting tool that analyzes all APCu operations on your site. It can report: KPIs: hit ratio, free memory, cached objects, keys saturation, memory fragmentation and availability; metrics variations; metrics distributions; plugins consumption. APCu Manager supports multisite report delegation (see FAQ). APCu Manager supports a set of WP-CLI commands to: toggle on/off main settings – see wp help apcu settings for details; obtain operational statistics – see wp help apcu analytics for details. For a full help on WP-CLI commands in APCu Manager, please read this guide. APCu Manager is part of PerfOps One, a suite of free and open source WordPress plugins dedicated to observability and operations performance. APCu Manager is a free and open source plugin for WordPress. It integrates many other free and open source works (as-is or modified). Please, see ‘about’ tab in the plugin settings to see the details. Support This plugin is free and provided without warranty of any kind. Use it at your own risk, I’m not responsible for any improper use of this plugin, nor for any damage it might cause to your site. Always backup all your data before installing a new plugin. Anyway, I’ll be glad to help you if you encounter issues when using this plugin. Please read carefully the FAQ at the bottom of this page before requesting support. Privacy This plugin, as any piece of software, is neither compliant nor non-compliant with privacy laws and regulations. It is your responsibility to use it with respect for the personal data of your users and applicable laws. This plugin doesn’t set any cookie in the user’s browser. This plugin doesn’t handle personally identifiable information (PII). Donation If you like this plugin or find it useful and want to thank me for the work done, please consider making a donation to La Quadrature Du Net or the Electronic Frontier Foundation which are advocacy groups defending the rights and freedoms of citizens on the Internet. By supporting them, you help the daily actions they perform to defend our fundamental freedoms!

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.