PHP Memory Leak Detection: Profiling Long-Running CLI Workers and Queue Consumers

Why Background Daemons Exhaust RAM

PHP was originally designed to terminate processes after each request, cleaning up memory automatically. However, in modern background queue workers (such as Laravel Horizon or Symfony Messenger), processes run continuously for hours or days. Memory leaks from unclosed file handles, static array growth, or unmanaged event listeners eventually crash the worker.

Debugging & Remediation Techniques

• Inspect memory_get_usage(true) inside processing loops.
• Explicitly trigger gc_collect_cycles() after processing massive datasets.
• Configure queue worker process recycling flags (e.g. --max-jobs=500 --max-time=3600).