عرض عملي: تجويع الخيوط في خدمة حية

خطوة بخطوة

1. Under load Shop slows then stops responding; CPU is low.
2. Take three thread dumps; most request threads are WAITING in Future.get or BLOCKED on one lock.
3. Find the owner thread and the code path holding the lock while doing remote I/O.
4. Planned mistake: restart the service and move on. Fix: save the dumps first; they are the evidence.
5. Move the remote call outside the critical section (or increase isolation with a separate pool); repeat the load test.
6. Confirm with a fresh dump and JFR lock-contention events that waiting is gone.