Overview
Many page caching plugins for WordPress offer fantastic performance increases for your website when used under the right conditions. In our experience, simply enabling page caching is an easy and relatively risk free task and provides the most benefit overall.
Some of these plugins also have the ability to “pre-load” the cache, meaning they will crawl your website and store a cached copy ready for when people visit the page.
Some of the most commonly used plugins with pre-loading are:
- WP Rocket
- WP Fastest Cache
- WP-Optimize
- W3 Total Cache
Unintended Issues
While in theory pre-loading cache sounds like a good idea, unfortunately it only works in perfect scenarios. One of the most common causes of excess CPU usage we’ve seen for WordPress sites is when this pre-loading is caught in a loop or takes too long to complete. At other times it’s a plugin which has excess resource issues, but can be triggered thousands of times as the caching plugin tries to pre-load the thousands of pages.
This can then have unintended consequences such as poor website performance through to the site being unavailable.
Recommendation
We recommend ensuring you disable any pre-loading features within your caching plugin.
While it may sound like this will slow your site down, the impact is very minimal. As long as you have even very minor traffic to your website or a Google Bot crawl your website, your site will be cached anyway.
If you clear your cache, there may be a small delay for the first visitor to the page as WordPress regenerates it however all subsequent visitors will have the benefit of a cached page.