Resolving WordPress transient cache buildup causing 504 Gateway Timeout on admin-ajax.php
Without a persistent object cache, WordPress stores every transient as two rows in wp_options, and an expired row is deleted only when get_transient() requests that exact key or when the daily delete_expired_transients cron event runs. Plugins that write per-request or per-user keys leave hundreds of thousands of rows that are never read again, and the … Read more