Mid-LevelPerformance & Load Testing
What is soak testing and when should you use it?
- soak testing
- endurance testing
- memory leaks
Answer it first, then compare. Nothing here is saved or scored.
Model answer
Soak (endurance) testing runs a moderate load for an extended period (4-24+ hours) to find issues that only appear over time: memory leaks, connection pool exhaustion, log file disk consumption, database connection leaks, and performance degradation from fragmentation. Use it before major releases or when you suspect resource leaks. Monitor resource trends, a slow upward crawl in memory usage indicates a leak even if the app performs fine in short tests.
What interviewers listen for
- Workload modellingYou design the load shape from product traffic, not from tool defaults.
- Percentile literacyYou read p50/p95/p99 separately and explain why each matters.
- Bottleneck triageYou correlate metrics across application, database, and infrastructure layers.
- Capacity instinctsYou can translate a soak test into a sizing or scaling recommendation.