Briefly describe the performance testing process?
1. Analyze performance requirements. Select the most frequently used scenarios by users to test, such as: login, search, order, etc. Determine the performance indicators, for example: the transaction pass rate is 100%, TOP99% is 5 seconds, the maximum concurrent users is 1000, and the CPU and memory usage rate is below 70%
2. Make a performance test plan, specify the test time (usually after the function is stable, such as the first round of testing) and the test environment and test tools
3. Write test cases
4. Build a test environment and prepare test data
5. Write performance test scripts
6. Performance test script tuning. Set checkpoints, parameterization, associations, rendezvous points, transactions, adjust think time, remove redundant scripts
7. Design test scenarios, run test scripts, monitor servers,
8. Analyze test results, collect relevant log bills of lading for development
9. Regression performance testing
10. Write test report
Performance Testing:
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How to determine the maximum load of the system?
Through the load test, the number of users is continuously increased. With the increase of the number of users, various performance indicators will change accordingly. When there is a performance inflection point, for example, when the number of users reaches a certain order of magnitude, the response time suddenly increases, then this The number of users corresponding to the inflection point is the maximum number of users that the system can carry.
Which places (which functions) of your system have been tested for performance?
Select the most frequently used functions by users for testing, such as: login, search, submit order
How do you determine the number of concurrent users?
1) It will be launched for a period of time first, and it will be estimated based on the collected user access data
2) Determine according to demand (use peak time period, number of registered users, single response time, etc.
In what environment are your performance tests performed?
Reference answer: We will build an independent performance testing environment for testing
When are your performance tests performed?
Benchmark test: After the functional test, do it when the system is relatively stable.
Load testing: in the dead of night, when no one is using the system
How to analyze performance test results?
First check the pass rate of things, and then analyze other performance indicators, such as confirming whether the response time, transaction pass rate, CPU and other indicators meet the requirements; if the test results are not credible, analyze the cause of the exception and retest after modification
What is the role of think_time?
Simulate real production user operations to examine the impact on the server.
After confirming that the performance test results are credible, if the following problems are found, locate the problems according to the ideas provided below
Problem 1: The response time is not up to standard
Check whether the transaction time is mainly spent on network transmission or the server. If it is the network, use the Throughput (network throughput) graph to calculate whether there is a bottleneck in the bandwidth. If there is a bottleneck, consider increasing the bandwidth or compressing the data transmission. Processing; if there is no bottleneck, then it may be caused by network instability. If the main time is spent on the server, it is necessary to check the CPU of the web server and the database server separately, and whether the memory usage is too high, because the high CPU and memory will definitely cause the response time to be too long. If it is a problem with the web server , take down the corresponding user operation log corresponding to the web server and send it to the development location; if it is a database problem, remove the corresponding log from the database server and send it to the development location.
Question 2: The CPU indicator of the server is abnormal
Analysis idea: Take down the corresponding user operation log on the web server and send it to the development location.
Question 3: The database CPU indicator is abnormal
Analysis idea: Take down the corresponding log on the database server and send it to the development location.
Problem 4: Memory Leaks
Analysis idea: Take out the heap data of the memory, analyze which object consumes the most memory, and then send it to the development location.
Question 5: The program runs successfully in a single-user scenario, but fails when running with multiple users, prompting that it cannot connect to the server.
Reason: The program may be a single-threaded processing mechanism
How to identify system bottlenecks?
From the analysis of TPS indicators, TPS is the number of transactions processed by the system per unit time. Observe whether the number of transactions that the system can process per second will also increase with the increase in the number of users
How to judge whether the performance of the system has improved or deteriorated
Comparing performance metrics with benchmarks
Where do your performance testing needs come from?
1: Customers provide requirements
2: Operation and maintenance provide requirements
3: Development provides demand
How to realize the concurrency of 200 users?
Add a rendezvous point after the request corresponding to the script
Under what circumstances do you want to associate, and how is the association done?
Use associations when the context of the script is related.
For example, the token association of login, adding, deleting, modifying and checking the primary key id association
With the verification code function, how to do performance testing?
1. Temporarily block the verification code, and restore it after completing the performance test
2. Use universal verification code
Do you perform performance testing in the foreground or in the background?
BS project: the test is the performance of the background server and the performance of the browser;
APP project: the performance of both mobile phone and server
What are the performance test indicators
Response time
throughput
cpu
Memory
io
disk
How script enhanced?
1. Do parameterization
2. Make association
3. Add a transaction
4. Add assertion
5. Add a rendezvous point
6. Add Think Time
