عرض عملي: التنبؤ بأحجام المجمّعات (pools) بقانون Little ثم القياس

خطوة بخطوة

1. Write the checkout budget and the expected load at 10×.
2. Compute required HTTP threads, DB connections, and Kafka consumers with Little's Law.
3. Run a load test (verify tool and setup before recording) and compare predicted with measured concurrency.
4. Planned mistake: use the average latency from a quiet run. Fix: use p95 latency under load; the model then matches within 20%.
5. Explain any remaining gap (retries, lock waits, GC).
6. Record the model and the measured error in the capacity plan.