FacetWP Caching Addon

For anyone with a few filter-heavy landing pages and highly repeated filters, not for sites with endless unique combinations

A filterable listing uses more resources than it seems: every time someone ticks a facet, FacetWP has to recalculate the available options for all the others. FacetWP Caching Addon stores those answers so they are not repeated.

It suits sites with heavily visited pages (a category landing page, for example) that have few facets and combinations people choose often. It does not suit sites where every visitor makes a different selection, such as typing their own location or mixing options at random: those combinations will not have been stored yet and the cache barely gets used.

What exactly FacetWP Caching Addon stores

It stores FacetWP's own AJAX requests in the database. Every unique combination of filters a visitor uses is saved and, the next time someone picks that same combination, it is served from the cache without recalculating anything.

It caches nothing else. That is why it coexists with other caching plugins such as WP Rocket: most of them deliberately ignore AJAX requests, so they do not step on each other. Think of it as a complement to your page cache, not a replacement.

How long the cache lasts and how to adjust it

By default, each entry expires after an hour (3600 seconds). If your content changes weekly or monthly, that is too short and it is worth extending. If it rarely changes, you can set a very long expiration and clear the cache by hand when needed.

• Global expiration: changed with a PHP filter (facetwp_cache_lifetime) that you add to your child theme's functions.php, a code snippets plugin or the Custom Hooks add-on.
• Per-page expiration: the same filter lets you set a different time for a specific URL, for example a products page that changes more often.

This requires touching code. If you are not comfortable with PHP, you will have to settle for the default hour or ask for help.

Clearing the cache without opening the database

When you are logged in, an FWP menu appears in the black admin bar. From there you can delete the whole cache or, if you are on a public page, just that page's cache. There are also PHP functions to delete what has expired, everything, or one specific page, useful if you want to automate it after updating content.

When the cache table does not fill up

On activation, the plugin tries to place a db.php symlink in the wp-content folder. That is its fragile point:

• Another plugin that also uses a db.php in the same place can cause a conflict.
• Some hosts block this kind of third-party caching.
• If wp-content is not writable, the link cannot be created.

To check that it works, browse a few facets and look in phpMyAdmin to confirm that the wp_facetwp_cache table exists (with the columns id, name, uri, value and expire) and has records. If your host prevents it, there is a manual alternative: create an empty db.php in wp-content and paste in the contents of the plugin's db.php; if it still does not fill up, talk to your host.

Frequently asked questions

Does it work without FacetWP?

No. It only caches FacetWP's AJAX requests, so it is an add-on that needs that plugin.

Is it compatible with WP Rocket?

Yes, they can be used together, because most caching plugins ignore AJAX requests and this one only stores its own.

Will it speed up a store with thousands of different filters?

Very little. The improvement shows up on high-traffic pages with few facets and combinations that repeat.

How do I know it is doing anything?

Check whether the wp_facetwp_cache table exists and fills up after using the filters on your site.

Can it be configured without code?

Clearing can, from the admin bar. Changing the expiration requires adding a PHP snippet.