Redis Object Cache

Redis Object Cache is a WordPress persistent object-cache drop-in manager. The plugin being active is not enough: persistent caching only runs when a valid wp-content/object-cache.php drop-in exists, WP_REDIS_DISABLED is not true, and WordPress can connect to Redis.

This skill is about WordPress/plugin integration with the OSS redis-cache plugin. It is not a Redis server installation or Linux service hardening guide.

When to use this skill

Trigger when ANY of the following is true:

• The task mentions Redis Object Cache, redis-cache, object-cache.php, persistent object cache, wp redis, WP_REDIS_*, PhpRedis, Predis, Relay, Redis cluster, sentinel, or object-cache diagnostics.
• A plugin stores expensive computed data with wp_cache_get() / wp_cache_set() and the site may have Redis Object Cache enabled.
• The user reports "Redis plugin is active but not working", "Object cache not enabled", "Drop-in missing/outdated/invalid", "Redis server unreachable", or "wp cache flush flushed too much".
• Code needs cache groups, TTLs, selective flush, non-persistent groups, or Redis Object Cache hooks.

Non-destructive checks first

Run these before changing anything: