Do you know the performance testing terms to be asked in the software testing interview?

Catalog

1、 What is load testing ？ What is performance testing ？

2、 What tests are included in the performance test ( At least mention 3 Kind of )

3、 What is the assembly point ? What's the point of setting a set point ?Loadrunner Which is the set point function in ?

4、 What is throughput ?

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

6、 What is the number of concurrent users ？ What is the number of online users ？ What is the number of system users ？

7、 What are parameters ？ Why create parameters ?

8、 What is Association ? The difference between automatic association and manual Association ？ How to find out where to relate ？

9、 What is? think time?think_time What's the usage? ?

10、IP What does cheating mean ？ When do you need to use IP cheating ?

11、 The three most important indicators that performance testing focuses on

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1、 What is load testing ？ What is performance testing ？

Performance testing is to get the system under certain conditions （ Including specific load conditions ） Performance index data of .

Load test is the system load that simulates the load condition of the actual software system , By constantly loading （ Such as gradually increasing the number of simulated users ） Or other loading methods to observe the response time and data throughput of the system under different loads 、 Resources occupied by the system （ Such as CPU、 Memory ） etc. , To test the behavior and characteristics of the system , In order to find the possible performance bottleneck of the system 、 Memory leak 、 Can't synchronize in real time . Load testing more embodies a method or a technology .

The stress test is under strong load （ Large amount of data 、 A large number of concurrent users, etc ） Next test , View the operating behavior of the application system in peak usage , So as to effectively find a function hidden trouble of the system 、 Whether the system has good fault tolerance and recoverability . The pressure test is divided into long time under high load （ Such as 24 hours ） The stability stress test and the destructive stress test leading to the collapse of the system under the extreme load condition .

                        

2、 What tests are included in the performance test ( At least mention 3 Kind of )

Pressure test 、 The load test 、 Reliable test 、 Big data test （ Database capacity test ）, The benchmark

3、 What is the assembly point ? What's the point of setting a set point ?Loadrunner Which is the set point function in ?

Marshal Point ： Simply speaking , Assembly point is used to realize “ Multi user concurrent testing ”, Because real concurrency doesn't exist , In order to realize concurrency more realistically , So set up assembly points where pressure is needed .

Set the set point function ：lr_rendezvous("Meeting");

4、 What is throughput ?

The number of client requests processed by the system in unit time .

Add ：

Data received by the client from the server per second , Or the number of transactions that the system server can process per second . Generally, as the number of virtual users increases , Throughput also increases , It shows that the network bandwidth is sufficient , conversely , Spit out as the number of virtual users increases , The throughput is relatively stable , In a straight line state , It generally means that the network bandwidth has become a bottleneck , Limited data transmission .

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

The throughput graph shows the number of bytes received by the virtual user from the server per second .

When the system throughput does not reach the system processing limit , The system performance will not decay , The average response time of transactions generally does not increase ;

When the system reaches the throughput limit , Client transactions are queued in the request queue , The waiting time is recorded in the response time , Therefore, the average response time of transactions will generally increase （ let me put it another way , The peak throughput and maximum response time occur almost at the same time ）.

6、 What is the number of concurrent users ？ What is the number of online users ？ What is the number of system users ？

Concurrency is mainly for servers , The key to concurrency is to see if user operations have an impact on the server . therefore , The correct understanding of the number of concurrent users is ： The number of online users who interact with the server at the same time , This interaction can be a one-way transmission of data , It can also be a two-way transmission of data .

Number of online users ： Simple understanding , The online quantity of the system in a certain period （ Whether logged in or not , Or whether there is interaction with the system . Pay attention to eliminate the session Timed out users ）.

Number of system users ： Number of users registered in the system .

                             

7、 What are parameters ？ Why create parameters ?

During performance testing , In order to simulate the actual situation more closely （ That is, for some information, you need to submit different data each time , Or use multiple different values for circular input ）, At this time, parameterization should be set , To submit application requests using multiple different values . Using parameterization can also reduce the size of the script .

8、 What is Association ? The difference between automatic association and manual Association ？ How to find out where to relate ？

【 The definition of relevance 】 To put it simply ： Association is a special kind of parameterization . It refers to some data returned by the client from the server （ such as sessionid）, Turn into dynamic data , Then send it as part of the next request . Or save the result data of the previous statement , Then use this data when submitting the request in the following statement .

【 The difference between automatic association and manual Association 】： Auto correlation is during script recording ( Set the automatic association option in the recording options ),VuGen According to the established rules , Automatically find the value that needs to be associated or after the script recording , Execute the script once , adopt Correlation Studio Automatically find the data that needs to be associated , And build relationships ; The way of manual correlation is usually to record two scripts of the same business process first （ Input the same data ）, You can use WinDiff And other text comparison tools , Find out the difference between the two scripts , That is to say, we need related data , Re pass web_reg_save_param Function to manually create an association , Parameterize the associated data used in the script . Because the data that needs to be correlated is relatively fixed （sessionid、sap-ext-sid、sap-wd-cltwndid、sap-wd-tstamp etc. ）, For skilled workers, only one recording is required .

9、 What is? think time?think_time What's the usage? ?

Thinking time is when real users are action Waiting time between . In short, it is to simulate the situation that different users spend different time when operating the same function process . By thinking about time , It can make us closer to the real situation in load testing .

10、IP What does cheating mean ？ When do you need to use IP cheating ?

Some products will harm visitors in order to avoid hacker attacks IP To judge , adopt IP Spoofing tools can bypass this limitation . For example, voting is right IP Uniqueness limits , Or gateway control .

11、 The three most important indicators that performance testing focuses on

TPS, Transaction response time , Throughput rate