Loading inefficiencies

It’s very easy to write code that works well but scales badly. Load testing is your chance to expose those issues by running new features with the heaviest loads your system is designed to sustain. Recall the example of the database query, which read all events since the beginning of time, gradually slowing the system down as time went on. There are many other examples.

Real-world example – 80 participants hang up

In one video company I worked at, we increased the maximum size of our meeting from 40 to 80 users. It was a massive project requiring changes throughout the system, but we finally got it running and were delighted to see so many participants connect successfully. There were huge congratulations all around; then, we finished the meeting, and all started to hang up.

However, that hanging up took a strangely long time. Panes flickered back and forth, and commands became unresponsive, but finally, after several confusing seconds...