Persistent PHP workers need discipline
A static array with the comment “cache, cleared per request”. It went to production on RoadRunner last month, and the memory graph turned into a staircase. PHP had one superpower nobody advertised: the request died. Every leak, every forgotten static, every open transaction was erased when the process shut down. Shared-nothing was not architecture. It was amnesia, and amnesia forgave us everything. RoadRunner and Swoole take it away. The worker lives for thousands of requests, and the class of bugs changes on the first day. That “per request” cache became a cache per worker lifetime, and the supervisor killed the process when it ran out of memory. A logger kept the request id in a property, so entries from user B carried the id of user A. And the best one: an exception in the middle of a Doctrine transaction left the connection with the transaction open, and the next request on that worker silently joined it. ...