Object caching helps WordPress load dynamic content faster by storing frequently used data in Redis, so WordPress doesn't have to ask the database for the same information again and again.
This is especially useful for pages that cannot be fully page cached, such as:
WooCommerce cart, checkout, and account pages
WordPress admin screens
Logged-in user pages
Membership, dashboard, or personalized content pages
What is Object Caching?
When WordPress loads a page, it needs to fetch a lot of data such as:
site settings
posts and pages
post metadata
menus
categories and tags
user information
query results
Normally, WordPress gets this data from the database every time a page is loaded.
With object caching enabled, that data is stored in Redis after it is generated once. The next time WordPress needs the same data, it can load it from Redis instead of asking the database again.
This reduces database work and helps dynamic pages load faster.
How it works
Imagine your homepage needs the site settings, navigation menu, recent posts, and a list of WooCommerce products.
Without object caching:
WordPress fetches that data from MySQL on every request.
With object caching:
First request: WordPress builds the page data and stores it in Redis
Next requests: WordPress reuses that cached data from Redis
This means WordPress has to do less work on future requests, which can improve performance and reduce database load.
Benefits
Reduce repeated MySQL queries
Improve dynamic page performance
Reduce CPU usage
Speed up logged-in and uncached requests
Reduce load on high-traffic sites
Requirements
FlyingPress Object Cache requires:
A WordPress site running FlyingPress
A Redis server accessible by your site
The PHP
phpredisextension installedPermission to write the
object-cache.phpdrop-in towp-content
Before enabling Object Cache, make sure Redis is installed and reachable from your server.
When to use it?
You want to speed up the WordPress admin area
Your site has dynamic, uncached content (e.g., user dashboards, cart pages)
How to Enable Object Cache
Go to FlyingPress → Caching → Object Caching
Enable Object Cache
If Redis is connected successfully, cache metrics and memory usage will start appear in the FlyingPress dashboard
If Redis connection is failed or anything goes wrong, then you'll see an error in the dashboard.
Drop-in object-cache.php
FlyingPress installs a WordPress object-cache.php drop-in in wp-content folder that intercepts WordPress object cache operations and stores persistent cache data in Redis.
Purging the Object Cache
You can purge the object cache from FlyingPress dashboard when needed. Purging the cache removes stored Redis objects so they can be rebuilt on the next request. This is useful when:
Testing changes
Troubleshooting stale data
Verifying cache behavior
Resetting cache state after a migration or environment change
After a purge, the first request to a page will be slower because the cache has to be re-build.
Cache Metrics
FlyingPress Object Cache includes cache metrics for last one hour so you can monitor how Redis is being used over time.
FlyingPress will show following metrics:
Cache hit ratio - Shows how often WordPress finds the requested data in Redis instead of rebuilding it.
Redis memory usage - Shows how much memory Redis is using to store cached objects.
These metrics help you understand whether your site is benefiting from object caching and whether the cache is being used effectively.
Configuration
In most cases, FlyingPress will connect to Redis automatically as soon as you enable Object Caching, provided Redis is available on your server.
However, some hosting providers use custom Redis connection details (for example, a different host, port, password, database, or Unix socket). In those cases, you’ll need to get the correct Redis configuration from your hosting provider and add the required constants to your wp-config.php file so FlyingPress can connect properly.
Constant | Purpose | Default |
| Redis host / server address |
|
| Redis port |
|
| Connection timeout in seconds |
|
| Redis username |
|
| Redis password |
|
| Redis database index to select |
|
| Connection type: |
|
| Unix socket path when using |
|
| Key prefix for cache keys | |
Make sure any these constants are added before this line:
/* That's all, stop editing! Happy publishing. */ require_once(ABSPATH . 'wp-settings.php');
FAQs
Does Object Cache replace page caching?
No. Object caching and page caching are different layers. Page caching stores final HTML, while object caching stores WordPress data and database query results.
Do I need Redis for FlyingPress Object Cache?
Yes. If Redis is not already available you can ask your hosting provider to install it on the server where your site is currently hosted.
Does object caching help WooCommerce?
Yes. Object caching can improve WooCommerce performance, especially on cart, checkout, My Account, logged-in user pages, etc.
Why is the first request slower after enabling object cache?
Because the cache is empty and needs to be populated. Later requests are a better measure of object cache performance.
Can I use another object cache plugin at the same time?
No. Only one object-cache.php drop-in can be active at a time. Running multiple object cache drop-ins together will cause conflicts.