Performance Testing Interview Questions

* Last updated 26/04/2020

** Performance Testing Basic Interview Questions**

1. What are the different types of performance testing?
2. What is the difference between stress and endurance testing?
3. how do you define the duration for an endurance test?
4. What is capacity testing?
5. Difference between capacity and stress testing?
6. What is capacity planning?
7. what are the phases of the performance testing lifecycle?
8. What information you gather in requirement gathering phase?
9. How will you decide the number of users for a load test?
10. How will you decide the number of users if the client does not have production statistics or the application is being launched for the first time?
11. What are the component of a test plan?
12. What is little's law? Ans
13. Calculate the number of users for a load test, if the target TPH is 3600 and script execution time is seconds including think time.
14. What all challenges you faced in the scripting phase?
15. How will you decide the performance testing tool to be used for a test ?
16. How will you decide the number of load generators required for a test ? Ans
17. What all challenges you faced in the execution phase?
18. What all things you include in your Performance Test Report?
19. What all performance bottleneck you have identified so far? Explain.
20. What is the 90th percentile?
21. Why do we consider the 90th percentile over 95th or 99th percentile?
22. Is there any possible scenario when the 90th percentile value is less than the average response time?
23. What is the difference between baseline and benchmarking?
24. What is the difference between concurrent and simultaneous users? Ans
25. What is the difference between synchronous and asynchronous calls?
26. What is Hit/sec?
27. What is Throughput?
28. What is the relation between hit/sec and throughput?
29. Difference between hit/sec and request/sec?
30. what is mean by different response codes 200, 300, 302, 400, 401, 403, 404, 500, 501, 502 503 ?
31. what is the difference between unauthorized (401) and forbidden (403) error?

**Loadrunner Interview Questions**
1. Which Loadrunner version you have worked upon?
2. What is the difference between HTTP/HTML and URL mode of recording?
3. What do you prefer between HTTP/HTML and URL mode?
4. What is the need of URL mode if HTTP/HTML is easy to script?
5. What is the difference between Socket Level and WinInet?
6. What is the difference between the first Vuser and second/other Vusers?
7. What is mean by Memory footprint?
8. Why the first Vuser consume more memory than other vusers?
9. What are the logging options available in Loadrunner ?
10. What is difference between standard and extended log?
11. What all functions you have used for correlation?
12. What are the arguments of web_reg_save_param ?
13. What is difference betweenweb_reg_save_param and web_reg_save_param_ex ?
14. How to handle dynamic left and right boundary in correlation.
15. What is the difference between web_reg_find and web_find ?
16. What are the parameters of web_reg_find ?
17. How can we implement error handling in LoadRunner ?
18. What is the use of lr_eval_string and lr_save_sring functions?
19. How can we create dynamics transaction names in LoadRunner ?
20. What are the graph merging options available in loadrunner analysis ?
21. What is granularity?
22. What are different the types of asynchronous calls in LoadRunner?
23. How can we handle async calls in loadrunner?
24. What is IP spoofing? How to implement IP spoofing?
25. How can you pass a correlation value from one script to another during the test execution?
26. What is the difference between running vuser as a process and thread?
27. Explain a scenario where you will prefer to run Vuer as a process instead of thread?
28. Why Vusesr as a process consume more memory?
29. What are the different types of scenarios available LoadRunneroadrunner controller?
30. What are the Options/Parameters available in goal-oriented scenario ?
31. How to define SLA in loadrunner controller ? What are the different parameters available to define SLA ?
32. What is the use of LoadRunner agent ?
33. What is the difference between basic and real-world scenario in the LoadRunner controller ?
34. What is randozvious point ?
35. What are the parameter types available in loadrunner?
36. What are the different functions available in LoadRunner to handle an array ?
37. What could be the possible issue, if you are getting an error on the very first request in your script?

**Trueclient Interview Questions**
38. What all challenges you faced in trueclient protocol ?
39. How to do parameterization in trueclient ?
40. What is the best method to resolve object identification issues in trueclient ?
41. Why trueclient need more load generators compared to HTTPP/HTML ?


** Performance Engineering Interview Questions**
1. What is memory leak ?
2. What are the different sections of heap memory in java.
3. How will you perform root cause analysis of a slow running transaction if you do not have any APM tool ?
4. What all performance counter you monitor from APM tool/ Perfmon/ Nmon ?
5. What is garbage collection?
6. What are the different garbage collection algorithms?
7. What are the different types of garbage collection ?
8. If your application is spending more time in garbage collection, What can be the possible root cause?
9. What is the command to take heap dump in java ?
10. What will be your approach to identify the root cause if you find sudden spike in CPU or Memory utilization of your application server during the load test ?
11. What is thread dump ?
12. What are the different states of a thread ?
13. What is multi-threading ?
14. What is deadlock ? explain with an example.
15. what are the different load balancing algorithms ?
16. What is threadpool ? What are the advantages of a threadpool ?
17. What is connection pool ? what are the advantages of a connection pool ?
18. How can you increase heap size in Java ?
19. Which is more performance efficient? query or stored procedure?
20. How would you detect and minimize memory leaks in Java?
21. What is auto-scaling ?
22. What is the difference between horizontal and vertical scaling?
23. In a web application, what is a CDN?
24. What are the benefits of CDN ?
25. What is Perm Gen space in the Java memory heap?
26. When does an Object becomes eligible for garbage collection in Java?