Memcached

Memcached Object Cache replaces the default transient and object cache with a persistent memcached backend, reducing database queries and speeding up page loads for sites with high traffic or complex data structures. It's intended for developers and site administrators who have access to a memcached server and the PECL memcache PHP extension.

• Persistent object cache: Stores database query results, transients, and other cached data in memcached memory, dramatically reducing load on the database server.
• Manual server specification: Define custom memcached servers and cache groups in wp-config.php, allowing you to route different types of cache (e.g., posts, options, users) to specific servers for optimal performance.
• Cache group support: Automatically handles over 30 cache groups (posts, terms, meta, etc.) and allows you to assign groups to dedicated memcached instances.
• Key salt for multi-site compatibility: Use the WP_CACHE_KEY_SALT constant to generate unique cache keys, preventing cache collisions when multiple sites share the same memcached server.
• Built-in stats page: Provides detailed metrics on cache hits, misses, and server performance, helping you monitor and tune caching behavior.

Installation requires copying the object-cache.php file to the wp-content directory (not the plugins folder), ensuring the PECL memcache extension and a memcached server are available, and adding a unique key salt to your configuration.