Quand le cache de Symfony ralentit votre application…
Summary
This article analyzes a production slowdown in a Symfony app caused by the Cache component's anti-stampede protection. Through production profiling, the team identifies the LockRegistry as the bottleneck, driven by DNS resolutions performed by Messenger workers. The fix isolates slow callbacks in a dedicated cache pool and replaces the per-lock approach with per-key locking to restore fast first visits and stabilize API endpoints.