What is load testing
A type of performance testing where you see how a system behaves under expected and peak load. Context matters, the intended use of your system & business context dictates how you’d model load expectations.
Some metrics to consider measuring
- Response time
- Throughput
- Memory/CPU utilization
- Error rate at peak load
- Concurrent user load
Before you begin load testing
Before you can start load testing, define production hardware constraints ahead of time. Establish what kind of memory, cpu, and network setup you have.
When is it appropriate to start load testing
The ‘shift left’ principle applies here. As soon as you can. While developing & throughout the development cycle. Memory profiling tools come in handy if you’re going to do this on your dev machine.
One step closer to production is running these tests in a staging environment.
Graceful degradation
Instead of complete/absolute failure of a system when it’s overloaded, load testing can help you figure out ahead of time what graceful degradation can look like.
- In some cases the answer is throttling clients that are making requests to your system
- In some cases it’s leaning real heavy on message queues
- In other cases it’s appropriate to drop requests altogether