Overview
The Performance Silent Killer
Understanding GC is vital for Non-Functional Testing. If a system's memory management is poorly tuned, it can lead to massive latency spikes under load.
When performing Soak Testing (running a system under load for long periods), QAs monitor the memory 'sawtooth' pattern created by Garbage Collection to ensure there are no memory leaks.
Our Recommendation
7/ 10
Best Practices
Dos and Don'ts
Avoid common mistakes that can lead to flaky tests and maintenance nightmares.
What to do
- •Monitor GC metrics during performance tests using tools like JVisualVM or New Relic.
- •Watch for 'Memory Leaks' where the baseline memory consumption keeps rising despite GC runs.
Common Pitfalls
- •Don't assume 'Automatic Memory Management' means 'No Memory Problems'.
- •Don't ignore high CPU usage that might be caused by a 'thrashing' Garbage Collector.
The Details
Analyzing the Memory Sawtooth
In a healthy system, memory usage should look like a sawtooth pattern: it rises as objects are created, then drops sharply as the Garbage Collector clears them. If the 'valleys' of the sawtooth are getting higher over time, you have identified a potential memory leak that will eventually crash the system in production.