W3 Total Cache Page Caching FAQ

This article lists some of the Frequently Asked Questions and Solutions regarding Page Caching and the different methods provided.

My pages are still showing old content

If cache invalidation is not occurring soon enough, resulting in pages showing expired content because the now invalid cache hasn’t been rebuilt, you may attempt the following:

• Adjust the Garbage Collection Interval under Page Cache > Advanced to a shorter interval.
  • This will force your page cache to be rebuilt more often, though keep in mind that adjusting this value may have an adverse performance impact if set too low.
• Adjust the Cache Preload settings under Page Cache > Cache Preload to automatically rebuild pages on a shorter interval
  • Ensure that you do not set the Update Interval too low or the Pages Per Interval too high, as this may have an adverse performance impact.
  • Consider providing a Sitemap URL, as this will allow you to specify the order in which pages are rebuilt.
• Switch to using an in-memory caching method as shown in the VPS / Dedicated Server or Multiple Server sections.

Another cause of pages showing old content may be that your dynamic content is being cached. You may attempt the following:

• Exclude pages that contain dynamic content from being cached under Page Cache > Advanced so that the entire page isn’t cached.
  • Note that if you have to add exclude rules for many pages, consider (add constant / use filter hook)
• If a page requires small amounts of dynamic content, you may still cache this page by using mfunc functionality or adjust the page logic to use AJAX calls to pull such content.

Enabling page caching didn’t improve my performance

Compare your page hit rate against the cache hit rate reported by your chosen method as when your cache hit rate is low, a plugin or your theme may be misusing or blocking page caching. You may check these values by:

• Enabling Page Cache debugging under General Settings > Debug Mode, which will append page statistics to the end of each HTML page when enabled.
  • Note: Ensure that this is only enabled for testing purposes, as it has a negative impact on performance.
• Consider upgrading to W3 Total Cache Pro, which provides access to the Statistics page that contains helpful information about all methods currently in use.

Be aware that all pages with query strings in the URL are not cached by default. You may attempt to reduce the impact of loading these pages by performing the following:

• Consider reducing the total number of pages that have query strings by adjusting your WordPress Permalinks settings to an option other than Plain.
• If a page requires a query string that is not likely to change or impact content, consider adding these URLs to Page Cache > Advanced > Accepted Query Strings so that they may be cached properly.