How did "he" get the offer? The most comprehensive collection of performance test interview questions + answers on the Internet (super comprehensive collection)

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Preface

1. What is load testing? What is performance testing?

Load testing is a kind of performance test that refers to whether the program can bear the data running in an overload environment. In this test, the test object will be made to bear different workloads to evaluate and evaluate the performance of the test object under different workload conditions. performance behavior, and the ability to continue to operate properly.

The goal of load testing is to determine and ensure that the system will function properly beyond the maximum expected workload. In addition, load testing evaluates performance characteristics such as response time, transaction processing rate, and other time-related aspects.

Performance testing mainly uses scenarios to test whether the performance of the software system meets production performance requirements, including load testing, strength testing, database capacity testing, benchmark testing and competition (concurrency, user) testing.

2. What tests does performance testing include? (Name at least three types)

Load testing, stress testing, stability testing, benchmark testing

3. Briefly describe the performance testing steps

Step 1: Requirements analysis, test plan, design test cases
Step 2: Test design and development (test script recording and debugging, test scenario design)
Step 3: Test execution (test environment setup, scenario deployment, scenario execution, monitoring Scenario)
Part 4: Test result analysis, performance problem location, test report evaluation

4. When can you start performing performance testing?

If the functional test is passed, systems that generally require performance testing are functional modules with a large number of users, frequent business use, and important functions.

5. What is the relationship between response time and throughput?

When the system throughput does not reach the system processing limit, the system performance will not decrease, and the average transaction response time will generally not increase.

When the system reaches the throughput limit, client transactions will be queued and waiting in the request queue, and the waiting time will be recorded in the response time, so the average transaction response time will generally increase.

6. What are the application fields of software performance testing?

Capability verification: Can a system have capability B under condition A? Capability
planning: How to make the system have the performance capabilities we require or what performance capabilities the system has under certain possible conditions?
Performance tuning, defect discovery.

7. Regarding the response time of the Web system, how many seconds is acceptable to users who are widely recognized in the industry?

2/5/10S

8. In performance testing, what performance indicators usually need to be paid attention to?

Response time, concurrency, throughput, system performance counters, think time

9. Please describe what throughput is?

The number of user requests processed by the system per unit time.
From a business perspective, throughput can be measured in units such as the number of requests/second, the number of services/second, the number of people/day, or the number of services processed/hour.

From a network perspective, throughput can be measured in bytes/second
. For interactive applications, the throughput indicator reflects the pressure on the server, which can illustrate the load capacity of the system.

10. What does TPS mean?

Number of transactions processed per unit time

11. Please give an example of generalized concurrency and strict concurrency?

Generalized concurrency: Generalized concurrency actually refers to the existence of virtual users who operate transactions within a period of time.
For the subway system, there are new people arriving and leaving every time, and everyone does basically the same thing.

Take the subway. Assume that there are 10,000 people in the subway hall at a certain time, 100 people waiting at the ticket gate, and
2,000 people on the subway that has just left. At this time, for the system (train) under investigation, the concurrent number is 2,000 people. If the inspection If it is the ticket check-in area, the number of concurrent passengers is 100.

Similarly, if the system under investigation is a subway hall, then the concurrency at this time is 10,000 people. This kind of concurrency is generally called "generalized concurrency".

Strict concurrency: refers to a large number of users performing exactly the same functional operations or the same type of functional operations on the software system at the same time. For example, flash sale products on Double Eleven

12. For a web system, what performance indicators are users most concerned about?

Response time

13. What does a performance testing plan usually contain?

Test purpose, test quality objectives, test environment, test phase and scope, test strategy, test schedule, test cases

14. How to identify performance bottlenecks?

Find out where the problem first occurred, that is, the shortcoming, and then analyze it.
First, make a performance test report on the existing system, such as CPU consumption, memory consumption, disk I/O, network card I/O, bandwidth, page exchange, etc.

If it is found that one or more of them have reached the bottleneck, then it is necessary to consider whether the hardware is insufficient and the performance cannot improve, or whether the system implementation is unreasonable and the system is full.

If it is a hardware problem, then consider expanding the capacity early.

If the resources have not reached their limit or it is confirmed that there is a problem with the system implementation, then it is necessary to dismantle the corresponding functions of the system or monitor the time consumption at the function level.

15. During performance testing, what resources of the OS need to be monitored?

cpu, memory, disk, network

16. Please explain what resource competition is?

Multiple users use the same thing, but this thing is locked by one person, resulting in resource competition and
competition lock.

17. The response time of the verification system is less than 3 seconds under 100 TPS. For such requirements, which performance testing method should be used?

Capability Assessment

18. From an administrator’s perspective, what indicators of system performance are we mainly concerned about?

① The response time of the system;
② Information related to the system status, such as: CPU, memory, application server status, JVM available memory, database status, etc.; ③ The scalability of the system,
the ability to handle concurrency;
④ The maximum possible capacity of the system , possible performance bottlenecks, which equipment can be replaced or which expansions can be made to improve system performance;
⑤ Whether long-term operation is stable enough, whether it can provide uninterrupted business services, etc.;

19. From the perspective of a development engineer, what indicators of system performance are we mainly concerned about?

System architecture: whether the architecture design is reasonable;
database design: whether there are problems in the database design;
code: whether there are performance problems in the code, whether there are unreasonable memory usage methods in the system;
design and code: whether there are unreasonable threads in the system Synchronization mode, whether there is unreasonable resource competition in the system

20. Please describe the difference between stress testing and load testing?

The expected result of the stress test is that problems occur in the system, and what we examine is the system's ability to handle problems.
Load testing is to examine the performance of a software system under a given load.
Stress testing allows us to identify the weaknesses of a system and how a program will perform under extreme load

21For a project that lacks clear performance requirements, how do you extract performance requirements?

Communicate with customers, check historical logs, compare with similar products, based on past experience

22. What should a complete performance test case contain?

Test case number, project title, test title, importance level, preset conditions, input, operation steps, output, test results, tester and time

23. What are the steps of performance testing and what is the most difficult part of performance testing?

Performance testing steps:
Preparation work, including verification of basic system functions, formation of test team, selection of tools, and pre-analysis of business scenarios.

Test Plan.
Test script design and development.
Test execution and management.
test analysis.

The most difficult part of performance testing:
It is difficult for performance testing to simulate real loads. In many cases, performance testing can only be used as a reference to find obvious performance problems. If you want to achieve 100% accuracy, you still need online real-time monitoring.

24. How to conduct performance testing and how to check its performance?

Performance requirements analysis: clarify whether performance testing is necessary, clarify the characteristics of the system under test, basic business, key business, user behavior, performance testing scope, performance testing goals and performance indicators, and performance testing strategy.

Carry out test case design, test script development and debugging, test environment and test data preparation.

Use jmeter tool for performance testing.

Obtain test data, optimize the system, and complete the test report.
If you use the jmeter testing tool, you can use the aggregation report to see its performance. Compare the performance test data with the test performance indicators. If the performance indicators are reached, it means that the performance is good.

The following is the most comprehensive software testing engineer learning knowledge architecture system diagram in 2023 that I compiled.

1. Python programming from entry to proficiency

2. Practical implementation of interface automation projects

3. Web automation project actual combat

4. Practical implementation of App automation project

5. Resumes of first-tier manufacturers

6. Test and develop DevOps system

7. Commonly used automated testing tools

8. JMeter performance test

9. Summary (little surprise at the end)

No matter how confused the road ahead is, the dream in your heart will always be the guiding light. Face challenges bravely and persist in hard work. Every effort is a treasure for growth. Believe in your own abilities and pursue your passion. You can only keep chasing and create your own glorious journey.

Working hard is the only way to realize your dreams, sharpen your will, surpass yourself, and move forward courageously. No matter how many setbacks and difficulties you encounter, persist in your faith, pursue bravely, and take one step at a time, you will eventually reach the top and compose your own magnificent poem.

On the stage of life, continuous struggle is the key to our growth and progress. No matter what challenges and difficulties we encounter, we must persist in believing in our own potential and value, face it bravely, and move forward firmly. Only in this way can we light up the hope in our hearts and create our own glory.