Persistent Object Cache
A Persistent Object Cache can reduce repeated database work by allowing WordPress to reuse cached data across separate requests.
WordPress uses an object cache for frequently accessed data such as options, posts, and metadata. By default, this cache exists only for the duration of a request and is discarded when the request ends. A persistent object cache allows eligible cached data to remain available across requests.
Data that WordPress core, plugins, or themes place in the WordPress Object Cache can persist across requests. This can include database-derived data, computed values, transients, or remote API responses when the application explicitly caches them.
Pressidium provides a Persistent Object Cache backed by Redis, an in-memory key/value store integrated with our caching infrastructure.
Persistent Object Cache can be particularly useful for database-intensive or dynamic requests that reach WordPress and PHP. The performance benefit depends on your site’s workload, plugins, themes, and data-access patterns.
What to know before enabling Persistent Object Cache
Persistent Object Cache is not enabled by default.
Before enabling it, verify that your plugins and themes are compatible with the WordPress Object Cache.
Potential issues can include:
- A large amount of autoloaded option data or unusually large cached objects.
- Plugins or themes that perform excessive object-cache reads and writes during a request.
- Workloads that frequently create or invalidate cached data, reducing how much cached data can be reused.
If possible, use a website clone to test your site’s behavior before enabling Persistent Object Cache on your live production website.
Additional resource: WordPress Object Cache reference
Manage Persistent Object Cache
You can enable, disable, and clear Persistent Object Cache from the Pressidium Dashboard. You can also clear the Object Cache from WordPress Admin.
Follow Manage Website Caches for the available controls and instructions.
Need help?
If persistent object cache causes unexpected behavior, or you are not sure whether it should be enabled for your site, contact our Support team before changing cache-related settings or code.
Where to go next
- Review how page cache works to understand the difference between full-page caching and object caching.
- Identify cache behavior using HTTP headers if you need to check whether a page is being served from cache.
- Programmatically disable the persistent object cache if custom code or plugin behavior requires object cache changes.
- Review access and error logs if cache-related behavior causes warnings, errors, or unexpected results.
Was this article helpful?