How Server-Sent Events Starve PHP-FPM Worker Pools

This article reveals a critical scalability issue for developers using SSE for real-time features on PHP-based servers. While SSE implementation appears sound in testing, the architecture fundamentally conflicts with PHP-FPM's worker pool model—each persistent connection occupies a worker indefinitely, quickly exhausting the pool and causing application failures under modest concurrent load. Understanding this incompatibility is essential for anyone considering real-time features in PHP infrastructure.