Object caching stores the results of expensive, repeated database queries in fast-access memory, so WordPress doesn't need to run the exact same query again every single time a page loads. It's a deeper, more technical layer of caching than standard page caching, and it can meaningfully improve performance on database-heavy sites.
How It Differs from Page Caching
- Page caching — stores a complete, finished HTML page for reuse
- Object caching — stores the individual results of specific database queries
When Object Caching Genuinely Helps
- Sites with heavy, dynamic content that can't simply be served as a static cached page
- WooCommerce stores, where inventory and pricing frequently change
- Membership sites showing different content to different logged-in users
- Any site under consistently heavy database load
Setting It Up
Object caching typically requires a persistent object cache backend like Redis or Memcached, configured at the server level, paired with a WordPress plugin such as Redis Object Cache to actually connect WordPress to it. Many managed WordPress hosts, including Kinsta and WP Engine, offer this built in.
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