Performance Testing Interview Questions and Answers

Performance Testing Interview Questions and Answers
Q. What is Performance testing?
Timing for both read and update transactions should be gathered to determine whether system functions are being performed in an acceptable timeframe. This should be done standalone and then in a multi user environment to determine the effect of multiple transactions on the timing of a single transaction.
Q. What is scalability testing?
1. Scalability is nothing but how many users that the application should handle
2. Scalability is nothing but maximum number of users that the system can handle
3. Scalability testing is a subtype of performance test where performance requirements for response time, throughput, and/or utilization are tested as load on the AUT is increased over time.
4. As a part of scalability testing we test the expandability of the application. In scalability we test 1.Application scalability, 2.Performance scalability
Application scalability: to test the possibility of implementing new features in the system or updating the existing features of the system. With the help of design doc we do this testing
Performance scalability: To test how the s/w perform when it is subjected to varying loads to measure and to evaluate the Performance behavior and the ability for the s/w to continue to function properly under different workloads.
–> To check the comfort level of an application in terms of user load. And user experience and system tolerance levels
–> The point within an application that when subjected to increasing workload begin to degrade in terms of end user experience and system tolerance
–> Response time
Execution time
System resource utilization
Network delays
Q. How to do the performance testing manually? Do you have a test case for that?
Performance testing can be done manually but the accuracy of results is adversely affected. We don’t have separate test cases for manual performance testing. This is taken care by the tool like Load runner, Web load etc.
Q What all things can be found out be performance testing?
Performance testing can be applied to understand the web site’s scalability, or to benchmark the performance in the environment of third party products such as servers and middleware for potential purchase.
Connection speed:
Tested over various Networks like Dial up, ISDN etc
Load
What is the no. of users per time?
Check for peak loads & how system behaves.
Large amount of data accessed by user.
Stress
Continuous load
Performance of memory, cpu, file handling etc.

Perfomanace Testing Tips

Perfomanace Testing Tips :

Do’s:

• After each performance test run, clear the logs for database and application. Large log files may result in inaccurate performance results.
• To mirror the production environment, identify the correct software and hardware for server.

• When a load is being generated on the system; to capture end user response time, use a single GUI client. If you need to generate load by using multiple client computers, you should consolidate data at single client computer / machine and generate results based on the average values.
• During a load test, include a buffer time between the incremental increases of users.
• To create a more realistic load simulation, always Use different data parameters for each simulated user.
• Never overly stress the client. Monitor all systems involved in the test including client that generates the load.
• According to high volume transactions and critical functionalities, prioritize your scenarios.
• If you need to fire concurrent requests, then, to identify bottleneck issues, use think time as zero.
• Do stress testing for critical components of the system to assess their independent thresholds.

Don’ts:

• During load testing, never ever allow test system resources to cross resource threshold limits from a significant margin – Otherwise, it will distorts the data in your results.
• For performance testing, always use an isolated test environment, but that environment should be exact replica of production environment. There should not be any other traffic load.
• Do not put too much stress on the client test systems.