Optimise WordPress¶

Up To Date Software¶

It’s important to keep on top of updating WordPress and its plugins to minimise risk from unpatched vulnerabilities, and updates may also include performance enhancements.

Automatic updates for themes and plugins are disabled by default but can be enabled in the wp-config.php file. This may not always be the preferred solution as the new versions could contain breaking changes that may impact the website. Available updates are visible through the WordPress admin panel and can be updated manually as they are released.

In addition to updating the application software, making sure that the server is running the latest software is also important for both security and performance reasons. This includes the Operating System, web server (Apache, NGINX, IIS, etc.), the database server (MySQL, MariaDB, MSSQL, etc.) and PHP.

Load¶

Server load is a major factor in the systems ability to handle requests quickly. Load average represents how many processes are queued waiting for compute resources, the higher the load average the slower the website will likely perform.

Identifying and blocking malicious traffic from accessing the server will reduce its impact on the servers load. WordPress brute force attacks are typical in the industry and are easily mitigated by using a .htpasswd or a security plugin like All In One.

Cache¶

Using a caching layer will temporarily store data in memory, meaning future requests for that content will be served from cache, resulting in a faster page load - in turn improving the user experience and reducing server load. Utilising a plugin like W3 Total Cache, WP Rocket, or WP Super Cache will provide the ability to cache static content and other features like “minifying” JavaScript and Cascading Style Sheets (CSS), as well as integrations into Content Delivery Network (CDN) platforms.

To take this to the next level, pairing these plugins with an in-memory datastore like redis or memcached can be very powerful. Feel free to contact support to discuss installing an in-memory cache on your server.

For clients running WordPress on Windows, take a look at Internet Information Services (IIS) tuning.

Installing php-opache on the server will improve PHP’s performance by storing precompiled bytecode in memory. Windows Servers can also look at Wincache.

Themes & Plugins¶

It’s fair to say that minimal, lightweight themes out-perform more complex graphic-heavy themes. It’s recommended that before choosing a WordPress theme, you first consider the impact it will have on the sites performance. A solid indicator of the quality are the:

• Ratings

• Reviews

• Documentation

• Support options provided

When talking about the homepage, it’s ideal to avoid heavy content both in terms of CPU time and in download time. The homepage is best kept minimal and ideally most (if not all) of the content being static files served via cache.

The more plugins that are installed and active, the more likely it is that the website will run slowly. Start by deactivating and deleting any unnecessary plugins. Then selectively disable remaining plugins to measure the performance before and after and see the impact it makes on page load. Is one plugin causing an obvious impact? Dig into the plugin documentation and support forums to make sure its working correctly, or look at an alternate plugin that provides the same functionality.

gzip Compression¶

Enabling gzip compression will reduce the size of the files sent from the server which increases the speed content is returned to the browser. When enabling compression you will notice the TTFB (Time To First Byte) will increase slightly. This is because the server is spending some time compressing the website files before the transfer, the overall page speed however should be quicker. For more information about TTFB, take a look at this Cloudflare article.

Optimise Images¶

Images that haven’t been optimised cause slower page load times, so it is recommended that these are optimised before use on your website.

• Use the correct file formats: JPG/PNG/GIF.

• Remove / crop white space around the images and instead use CSS for padding.

• Save images in the desired size to reduce the file size.

Lossless compression is a method of compressing the size of a file without sacrificing image quality. This can be done using a plugin like smush (if suitable) or per image using an online resizing tool.

Minify CSS & JavaScript¶

Minification is the action of removing white space and unnecessary characters from a file to reduce the total size of that file. When CSS and JavaScript are minified the page load time is decreased as the CSS and JavaScript files are smaller.

Defer JavaScript¶

By default, JavaScript blocks Document Object Model (DOM) rendering which delays the time it takes the browser to display the page. Some JavaScript execution is not necessary for the initial render and can be deferred to execute after the page has loaded. Also see Parser Blocking vs. Asynchronous JavaScript for details on loading JavaScript asynchronously.

Windows Application Pool¶

To prevent memory leaks or unresponsive/idle worker processes within the application causing performance issues, its recommended to setup nightly recycling in the IIS application pool. In additional to recycling, requests to the application pool can be limited using the Queue Length parameter in the application pool settings. To prevent high demand causing degraded website performance there is an algorithm that can suggest the optimal queue length ( Available memory in MB x number of processors x 10 ) / ( total number of application pools ).

Database Tuning¶

• WordPress on MSSQL

• WordPress on MySQL/MariaDB