Queue Length Doesn't Tell the Whole Story

A queue's size is only a snapshot in time.

To understand system health, measure arrival rate, processing rate, and whether the backlog is growing or shrinking.

A long queue might be stable. A short queue might be about to overflow.

Without rate metrics, you're reacting to a number — not diagnosing a system.

Measure inflow. Measure outflow. Measure the delta.

That's how you know if you're keeping up.