wp-query-cache

Prevent stale data in WordPress query cache by replacing direct object-cache writes with salted helpers like wp_cache_get_salted and wp_cache_set_salted, which use last_changed salts across query groups to maintain cache correctness and invalidate outdated keys.

Salted cache helpers in WordPress are functions like wp_cache_get_salted and wp_cache_set_salted that use last_changed salts for cache invalidation. Use them for post-queries, term-queries, and user-queries to safely optimize expensive reads and ensure bug-safe cache invalidation with persistent object cache.

Refactor direct object-cache writes in WordPress plugins by auditing plugin code and replacing manual cache writes with salted cache helpers and native WP_Query APIs, ensuring proper cache invalidation across query groups and preventing stale reads.

Use core WP_Query APIs instead of manual cache writes for WordPress queries because manual object-cache writes lead to stale data, whereas native APIs handle invalidation internally via last_changed salts, ensuring correctness across post-queries and term-queries.

WordPress 6.9+ supports salted cache helpers like wp_cache_get_salted and wp_cache_set_salted for query groups including post-queries, term-queries, and user-queries, applying last_changed salts to maintain cache correctness and reduce stale keys in persistent object cache scenarios.

WordPress term-queries return stale cached results when plugins bypass salted cache helpers and use direct object-cache writes, because without last_changed salts applied to query groups, cache invalidation fails and outdated keys persist in the persistent object cache.