Certified Tester Performance Testing
Domain 1Objective 6
Common Performance Efficiency Failure Modes and Their Causes CT-PT Practice Questions (Page 2)
Part of the Basic Concepts domain, which makes up ~25% of our current practice bank. ISTQB does not publish an official question count, but from its 90-minute exam (~35–60 total, ~9–15 in this domain), expect 2–3 from this objective — we provide 12 practice questions to prepare you well beyond it. (estimate)
12questions here
3free pages
3concepts
Questions 6–10
- 6
A social media application's news feed takes 8 seconds to load during peak hours. Monitoring shows the API gateway is healthy, but the feed service makes 15 sequential calls to a user-profile service for each feed request. The profile service has a 500ms response time per call. Which failure mode is most directly indicated?
Select an answer first - 7
A retail company's e-commerce site shows a steady increase in response time during a 30-minute load test. Monitoring shows CPU utilization on the application servers plateaus at 95% after 10 minutes, while database CPU stays under 30%. The application code uses a nested loop to validate each item in a shopping cart against a product catalog that is re-fetched from the database for every item. Which cause is most directly responsible for the observed failure mode?
Select an answer first - 8
A system experiences slow response times under peak load. Analysis reveals that a critical section of code uses a nested loop that processes data in O(n^2) time. Which cause is most directly linked to this failure mode?
Select an answer first - 9
A logistics company's tracking portal performs well in functional testing with 10 users. In a load test with 200 users, the portal becomes unresponsive, and the application server's memory usage grows until the process crashes. The application loads the entire shipment history for a user into memory when they log in. Which cause is the primary reason for the failure?
Select an answer first - 10
Which of the following is an example of a performance efficiency failure mode?
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