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Speed Up Your WordPress Site with Object Cache

Object Cache is a powerful performance feature that dramatically speeds up your WordPress site by storing frequently accessed data in memory. Instead of querying the database for every request, WordPress retrieves cached data instantly, resulting in 70-90% fewer database queries and 2-5x faster page load times.


In this documentation, we will explore:



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This feature is available in Plus plans and above. View Pricing here. If you are not logged in, use this link to view pricing.


What is Object Cache?


Object Cache is a persistent caching system for WordPress that stores database query results in memory using Valkey (a Redis-compatible technology). When your site receives a request, WordPress checks the cache first before hitting the database, dramatically improving performance.


How Does It Work?


Without object cache, WordPress makes 100-200 database queries for every page load. With object cache enabled:


  1. WordPress checks if data is already cached in memory
  2. If found (cache hit), data is retrieved instantly
  3. If not found (cache miss), data is fetched from database and stored in cache
  4. Subsequent requests use the cached data (no database query needed)


Why Use Object Cache?


  • Faster Page Loads: Reduce page load times by 2-5x (from 2-5 seconds to 0.5-1.5 seconds)
  • Fewer Database Queries: Reduce database queries by 70-90% (from 100-200 to 10-30 per page)
  • Better Performance During Traffic Spikes: Handle more visitors without slowing down
  • Reduced Server Load: Lower CPU and MySQL usage by 30-80%
  • Improved User Experience: Faster sites lead to better engagement and SEO rankings


Who Should Use This Feature?


  • High-Traffic Sites: Handle thousands of visitors without performance degradation
  • E-Commerce Sites: Speed up product pages and checkout processes
  • Content-Heavy Sites: Quickly serve blogs, news sites, and magazines
  • Membership Sites: Improve performance for logged-in users


Technology Behind Object Cache


InstaWP uses Valkey, a high-performance, Redis-compatible in-memory data store, combined with the industry-standard Redis Object Cache WordPress plugin. Your data is stored securely with isolated access per site, ensuring no data leakage between different websites.


How to Enable Object Cache


Follow these simple steps to enable Object Cache for your InstaWP site:


Step 1: Navigate to your Sites page in the InstaWP dashboard.



Step 2: Click on your site to open the site management panel




Step 3: Then click Object Cache in the left sidebar menu and On the Object Cache page, you'll see information about the feature and a toggle switch.



Step 4: Toggle the Enable Object Cache switch to ON.




Step 5: Wait a few seconds while InstaWP sets up object caching for your site. The system will:

  • Install the Redis Object Cache WordPress plugin
  • Configure secure cache credentials
  • Enable caching for your WordPress site


Step 6: Once enabled, you'll see a success message and the Clear Cache button will appear.


✅ Object Cache Enabled! Your WordPress site is now using in-memory caching. You should notice faster page loads immediately. The first few requests will populate the cache, and subsequent requests will be lightning-fast.


Verifying Object Cache is Working


To verify that object cache is actively improving your site's performance:


Method 1: Check WordPress Admin

  1. Log into your WordPress admin dashboard
  2. Go to Settings → Redis
  3. You should see "Status: Connected" with cache statistics


Method 2: Monitor Page Load Speed

  • Use browser developer tools (F12 → Network tab)
  • Compare page load times before and after enabling cache
  • You should see significantly reduced load times


Method 3: Check Database Queries

  • Install a query monitor plugin (temporary)
  • Check the number of database queries per page
  • Should see 70-90% reduction in query count


How to Clear Cache


Sometimes you need to clear cached data, such as after:

  • Making content updates that aren't reflecting on your site
  • Changing theme or plugin settings
  • Troubleshooting display issues


Step 1: On the Object Cache page, locate the Clear Cache button (visible when cache is enabled).




Step 2: Click the Clear Cache button.


Step 3: Wait for the confirmation message.



Note: Clearing the cache is safe and won't harm your site. The cache will automatically rebuild as visitors browse your site. You may notice slightly slower page loads immediately after clearing, but performance will quickly return to normal as the cache repopulates.


When to Clear Cache


Clear your cache when:

  • Content not updating: New posts or page changes aren't visible
  • Theme/plugin changes: After activating or configuring plugins
  • Troubleshooting: Investigating display or functionality issues
  • Testing: Verifying changes during development


Automatic Cache Clearing


The cache automatically clears or updates when you:

  • Publish or update posts/pages
  • Change site settings
  • Activate/deactivate plugins
  • Update WordPress core


How to Disable Object Cache


If you need to disable Object Cache (for troubleshooting or if no longer needed):


Step 1: Go to your site's Object Cache page.


Step 2: Toggle the Enable Object Cache switch to OFF.


Step 3: InstaWP will automatically:

  • Clear all cached data
  • Remove the cache configuration
  • Deactivate the Redis plugin
  • Return your site to standard database queries


Step 4: You'll see a confirmation message when the process is complete.



Important: Your site will continue to function normally after disabling object cache, but page load times will return to pre-cache levels. Database queries will increase, so consider keeping cache enabled for best performance.


Troubleshooting


Connection Issues


Problem: Object cache won't enable or shows connection error.


Solutions:

  • Wait 30 seconds and try toggling again (cache setup may need time)
  • Check that your WordPress installation is working properly
  • Verify you're on a Plus plan or higher
  • Contact support if the issue persists



Problem: WordPress admin shows "Status: Not Connected" even though cache is enabled.


Solutions:

  • Clear your cache using the Clear Cache button
  • Disable and re-enable object cache
  • Check that the Redis Object Cache plugin is active in WordPress (Plugins → Installed Plugins)
  • Try disabling other caching plugins that might conflict (W3 Total Cache, WP Super Cache, etc.)



Performance Issues


Problem: Site is slower after enabling object cache.


Solutions:

  • Clear the cache (it may have stale data)
  • Wait 5-10 minutes for the cache to warm up properly
  • Check if you're on a high-traffic site (first requests after enabling are slower while building cache)
  • Disable other caching plugins that might conflict



Problem: Changes to site aren't showing up.


Solutions:

  • Click the Clear Cache button to remove stale data
  • Wait 30 seconds for cache to clear
  • Hard refresh your browser (Ctrl+F5 or Cmd+Shift+R)
  • Check if changes were actually saved in WordPress admin



Plugin Conflicts


Problem: Site shows errors after enabling cache.


Solutions:

  • Disable object cache immediately
  • Check WordPress error logs for specific error messages
  • Identify conflicting plugin (try disabling plugins one by one)
  • Some plugins incompatible with object caching:
  • Certain security plugins with aggressive caching
  • Old or poorly-coded plugins
  • Custom caching plugins
  • Re-enable object cache after removing conflicting plugin



Problem: Website shows 500 error.


Solutions:

  • This is usually a temporary issue during setup
  • Wait 2-3 minutes and refresh
  • If persistent, disable object cache
  • Check that wp-content/object-cache.php drop-in file isn't corrupted
  • Contact support for assistance



FAQs


How much faster will my site be?


Most sites see 2-5x improvement in page load times. Results depend on:

  • Current site speed (slower sites see bigger improvements)
  • Number of database queries (query-heavy sites benefit most)
  • Traffic patterns (high-traffic sites see consistent gains)
  • Content types (dynamic content benefits more than static)


Typical improvements:

  • Page load time: 2-5 seconds → 0.5-1.5 seconds
  • Database queries: 100-200 → 10-30 per page
  • Server CPU usage: 30-50% reduction



Does object cache work with other caching plugins?


Object cache works at a different level than page caching plugins:

  • Object Cache: Caches database query results
  • Page Cache: Caches entire HTML pages


You can use both together for maximum performance, but:

  • ✅ Compatible: WP Rocket, LiteSpeed Cache (when properly configured)
  • ⚠️ May Conflict: W3 Total Cache, WP Super Cache (if they have their own object caching)
  • Recommendation: Use InstaWP Object Cache + a good page cache plugin for best results


How much memory does object cache use?


Each site gets 50MB of cache memory by default, which is sufficient for most websites. This memory is used to store:

  • Database query results
  • WordPress options and settings
  • Post and page data
  • User and metadata
  • Plugin and theme data


50MB typically stores:

  • 10,000+ cached items
  • Several hours of high-traffic caching
  • All frequently accessed data


Does object cache affect logged-in users?


Yes, object cache benefits all users including:

  • Logged-out visitors (public content)
  • Logged-in users (personalized content)
  • Site administrators (admin dashboard)


Some caching is user-specific to ensure personalized content displays correctly. For example:

  • Public homepage: Shared cache (all visitors see same data)
  • User profile page: User-specific cache (each user has own data)
  • Shopping cart: Session-specific cache (personal data)



How is my cache data secured?


InstaWP uses ACL-based isolation to ensure your cache data is completely private:


  • Separate credentials for each site (unique username and password)
  • Isolated namespace (your keys can't be accessed by other sites)
  • Encrypted passwords (stored securely in database)
  • No cross-site access (impossible to read other sites' data)


Your cache data is as secure as your database data.



💡 Did you know - You can also improve site performance by enabling CDN, optimizing images, and using a fast theme. Object cache is just one part of a comprehensive performance strategy!






Updated on: 13/11/2025

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