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性能测试人员面试经典技术问题(汇总)----果然经典
上一篇 / 下一篇 2010-09-02 10:06:34 / 个人分类：性能测试理论
第一篇：性能测试人员面试经典技术问题
1.请问什么是性能测试、负载测试、压力测试？
原参考答案：
性能测试：对一个软件系统而言，包括执行效率、资源占用、系统稳定性、安全性兼容性、可扩展性等。
负载测试：通过逐步加压的方式来确定系统的处理能力，确定系统能承受的各项阀值。
压力测试：逐步增加负载，使系统某些资源达到饱和甚至失效的测试。
个人理解：
经典的问题，答案打算参考段念的书:
性能测试（Performance Testing）：是通过模拟系统实际运行的压力和使用场景组合，测试系统的性能是否满足实际生产的性能要求。
特点：1.主要目的是验证系统是否具备其宣称的能力
2.需要事先了解被测系统的典型场景，并具有确定的性能目标
3.要求在已确定的环境下运行
负载测试(Load Testing):通过在被测系统上不断增加压力，直到某个性能指标超过预定指标或者某种资源使用已经达到饱和状态
特点：1. 主要目的是找到系统处理能力的极限，为系统调优提供数据。测试形式/手段："检测--加压--知道性能指标超过预期"
2.在给定的测试环境下进行，考虑被测系统的业务压力量和典型场景
3. 一般用来了解系统的性能容量，或是配合性能调优
压力测试(Stress Testing)：测试系统在一定饱和状态下(CPU/MEMORY)，
特点：1. 主要目的是检查系统处于压力情况下时，应用的表现
2. 一般用于测试系统的稳定性
2.请分别针对性能测试、负载测试和压力测试试举一个简单的例子？
原参考答案：
性能测试例子：公司开发了一个小型项目管理系统，上线前需要做负载、压力、大数据量、强度测试等。
负载测试：逐步加压，从而得到“响应时间不超过10秒”，“服务器平均CPU利用率低于85%”等指标阀值。
压力测试：逐步加压，从而使“响应时间超过10秒”，“服务器平均CPU利用率高于90%”等指标来确定系统能承受的最大负载量。
3.请例举出常用的性能测试工具，并指出这些工具的优缺点？
LoadRunner，录制脚本快捷操作简便，需要一定的学习时间，有采购成本。
4.请问您是如何得到性能测试需求？怎样针对需求设计、分析是否达到需求？
在查看需求文档，从中提取性能测试需求，与用户交流，了解实际使用情况。
结合业务信息设计操作场景总结出需测试的性能关键指标。
执行用例后根据提取关键性能指标来分析是否满足性能需求。
5.什么时候可以开始执行性能测试？
在产品相对比较稳定，功能测试结束后。灵活性比较强。
6.什么是集合点？设置集合点有什么意义？LoadRunner中设置集合点的函数是哪个？
集合点可以控制各个Vuser以便在同一时刻执行任务。
借助集合点，可以再LoadRunner中实现真正意义上的并发。
lr_rendezvous()
7.性能测试时，是不是必须进行参数化？为什么要创建参数？LoadRunner中如何创建参数？
8是。
模拟用户真实的业务操作。
创建参数列表，用参数替换固定的文本。
8.您了解关联吗？如何找出哪里需要关联？请给一些您所在项目的实例。
了解。
使用LoadRunner自动关联功能。手动关联：录制两份相同操作步骤的脚本，找出不同的部分进行判断。
一个项目管理系统，每次登录后服务器都自动分配一个sessionID以便之后每次表单提交后验证。
9.您如何调试LoadRunner脚本？
设置断点、增加log。
10.在LoadRunner中如何编写自定义函数？请给出一个您在以前项目中编写的函数。
11.请问您是如何理解LoadRunner中集合点、事务以及检查点等概念？
集合点：可以控制各个Vuser以便在同一时刻执行任务，可实现真正意义上的并发。
事务：事务是用来度量服务器响应时间的操作集。
检查点：在回放脚本期间搜索特定内容，从而验证服务器响应内容的正确性。
12.如何应用LoadRunner进行性能测试？
使用虚拟用户生成器创建脚本，使用控制器设定场景、运行脚本，使用分析器分析运行后得到的数据。
13.LoadRunner中思考时间有什么作用？
用户执行两个连续操作期间等待的时间。模拟用户真实的使用情况。
14.LoadRunner中如何实现多用户并发操作，需要进行哪些设置？
设置集合点来实现，在脚本中加入lr_rendezvous()，然后可以在控制器中设定集结百分比。
15.LoadRunner中有基于目标和手动两种场景设计方式，他们分别适用于什么情况？
手动场景可按照要求来配置场景，能够更加精确的满足测试需要。
目标场景要先制定希望实现的测试目标，然后由控制器惊醒自动测试评估。
16.LoadRunner中有几种并发执行策略，它们的含义是什么？
三种。1.当所有虚拟用户中的x%到达集合点时释放。2.当所有正在运行的虚拟用户中的x%到达集合点时释放。3.当x个虚拟用户到达集合点时释放。
17.有5台配置为处理器：Intel Pentium 4 1.6G，内存容量 512MB，硬盘容量 40GB的机器，如何较好的利用这些机器完成一次并发用户数为1000人的性能测试工作？
1台做应用服务器，1台做数据库服务器，1台运行控制器并承担一部分负载生成任务，2台负载生成器。
18.平时大家在注册邮箱等关联操作时，经常会遇到需要输入验证码的情况，请问，如果我们公司也开发了一套带验证码的应用软件，需要警醒性能测试，您会如何处理？
留一个后门，我们设定一个所谓的“万能验证码”，只要用户输入这个“万能验证码”，系统就验证通过。测试完成后补上后门。
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第二篇：性能测试面试题(参考第四篇的英文题目及答案)
1.什么是负载测试？什么是性能测试？
2.性能测试包含了哪些测试（至少举出3种）
3.简述性能测试的步骤
4.简述使用Loadrunner的步骤
5.什么时候可以开始执行性能测试？
6.LoadRunner由哪些部件组成？
7.你使用LoadRunner的哪个部件来录制脚本？
8.LoadRunner的哪个部件可以模拟多用户并发下回放脚本？
9.什么是集合点？设置集合点有什么意义?Loadrunner中设置集合点的函数是哪个?
10.什么是场景？场景的重要性有哪些?如何设置场景?
11.请解释一下如何录制web脚本？
12.为什么要创建参数?如何创建参数?
13.什么是关联？请解释一下自动关联和手动关联的不同。
14.你如何找出哪里需要关联？请给一些你所在项目的实例。
15.你在哪里设置自动关联选项？
16.哪个函数是用来截取虚拟用户脚本中的动态值？（手工管联）
17.你在VUGen中何时选择关闭日志？何时选择标准和扩展日志？
18.你如何调试LoadRunner脚本？
19你在LR中如何编写自定义函数？请给出一些你在以前进行的项目中编写的函数。
20.在运行设置下你能更改那些设置？
21.你在不同的环境下如何设置迭代？
22.你如何在负载测试模式下执行功能测试？
23.什么是逐步递增？你如何来设置？
24.以线程方式运行的虚拟用户有哪些优点？
25.当你需要在出错时停止执行脚本，你怎么做？
26.响应时间和吞吐量之间的关系是什么？
27.说明一下如何在LR中配置系统计数器？
28.你如何识别性能瓶颈？
29.如果web服务器、数据库以及网络都正常，问题会出在哪里？
30.如何发现web服务器的相关问题？
31.如何发现数据库的相关问题？
32.解释所有web录制配置？
33.解释一下覆盖图和关联图的区别？
34.你如何设计负载？标准是什么？
35.Vuser_init中包括什么内容？
36. Vuser_end中包括什么内容？
37.什么是think time？think_time有什么用？
38.标准日志和扩展日志的区别是什么？
39.解释以下函数及他们的不同之处。
Lr_debug_message
Lr_output_message
Lr_error_message
Lrd_stmt
Lrd_fetch
40.什么是吞吐量？
41.场景设置有哪几种方法
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第三篇：性能测试面试题
1、 【测试理论】描述不同的角色（用户、产品开发人员、系统管理员）各自关注的软件性能要点。
2、 【测试理论】解释5个常用的性能指标的名称与具体含义。
3、 【测试流程】简述性能测试流程与各阶段的工作内容。
4、 【LR工具】web系统中，username参数表为file类型，表中有12个值，分别A、B、C、D、E、F、G、H、I、J、K、L。
测试场景中虚拟并发用户数设为4，迭代次数设为3，
参数中Select next row与Update value on分别为(Sequential, Each Iteration)与(Unique, Once)时，
写出迭代3次的取值情况。
（Select next row， Update value on） 虚拟用户取值（VUi：迭代时取值）
（Sequential， Each Iteration）
VU1：
VU2：
VU3：
VU4：
（Unique， Once）
VU1：
VU2：
VU3：
VU4：
5、【LR工具】web系统脚本录制过程中，两次录制同一功能点，在View Tree的Server Response中产生的字符串分别为：
Server Response：name="_id_Node " value=" RSDP0013425" />", ENDITEM,
Server Response：name="_id_Node " value=" RSDP1203655" />", ENDITEM,
为脚本回放成功，需要对字符串中某些字符做一定处理，写出详细实现方法。
6、 【数据库应用】现有Customers表和Sales表的数据如下：
Customers表：
CustID Name ShpCity Discount
449320 Adapto PortLand 0.05
890003 AA PortLand 0.05
888402 Seaworth Albany 0.04
Sales表：
SaleID CustID SaleMount
234112 499320 8000
234113 888402 6500
234114 499320 5900
234115 890003 4500
要求：
1） 给出查询语句，描述：在Customers表中查询名字为AA或Bolt的查询语句；
2） 给出删除操作，描述：在Sales表中删除SaleID为234115的语句。
3） 根据以下结果表给出多表查询语句。
SaleID CustID Name Discount SaleMount
234112 499320 Adapto 0.05 8000
234113 888402 Seaworth 0.04 6500
234114 499320 Adapto 0.05 5900
234115 890003 AA 0.05 4500
7、 【数据库应用】为了尽可能避免大表全表扫描，最常见的方法有哪些？
8、 【中间件】WebLogic参数调整中，列举三项影响并发性能的参数项并简述其含义。
9、 【Unix命令】HP-UX与AIX操作系统中，监控CPU、内存、磁盘I/O的命令分别是什么？
10、 【Unix命令】用命令实现：
1） 对文件FileA添加读、写、执行权限；
2） 列出当前系统与java相关的活动进程；
3） 搜索当前文件夹中所有的.sh文件。
11、 【网络】服务器ip地址为128.64.96.100，HP-UX操作系统，ftp服务开启，用户名与密码分别为username/password, /home目录下有一个monitor.svc文件，现需要将monitor.svc文件取到客户机192.168.2.100，服务器与客户机二者之间网络互通，描述在192.168.2.100上操作过程
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第四篇： 45道性能测试的面试题及答案（In English）
1. What is load testing?
- Load testing is to test that if the application works fine with the loads that result from large number of simultaneous users, transactions and to determine weather it can handle peak usage periods.
2. 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.
3. Did u use LoadRunner? What version?
- Yes. Version x.x .
4. Explain the Load testing process? -
Step 1: Planning the test. Here, we develop a clearly defined test plan to ensure the test scenarios we develop will accomplish load-testing objectives.
Step 2: Creating Vusers. Here, we create Vuser scripts that contain tasks performed by each Vuser, tasks performed by Vusers as a whole, and tasks measured as transactions.
Step 3: Creating the scenario. A scenario describes the events that occur during a testing session. It includes a list of machines, scripts, and Vusers that run during the scenario. We create scenarios using LoadRunner Controller. We can create manual scenarios as well as goal-oriented scenarios. In manual scenarios, we define the number of Vusers, the load generator machines, and percentage of Vusers to be assigned to each script. For web tests, we may create a goal-oriented scenario where we define the goal that our test has to achieve. LoadRunner automatically builds a scenario for us.
Step 4: Running the scenario.We emulate load on the server by instructing multiple Vusers to perform. tasks simultaneously. Before the testing, we set the scenario configuration and scheduling. We can run the entire scenario, Vuser groups, or individual Vusers.
Step 5: Monitoring the scenario.We monitor scenario execution using the LoadRunner online runtime, transaction, system resource, Web resource, Web server resource, Web application server resource, database server resource, network delay, streaming media resource, firewall server resource, ERP server resource, and Java performance monitors.
Step 6: Analyzing test results. During scenario execution, LoadRunner records the performance of the application under different loads. We use LoadRunner’s graphs and reports to analyze the application’s performance.
5. When do you do load and performance Testing?
- We perform. load testing once we are done with interface (GUI) testing. Modern system architectures are large and complex. Whereas single user testing primarily on functionality and user interface of a system component, application testing focuses on performance and reliability of an entire system. For example, a typical application-testing scenario might depict 1000 users logging in simultaneously to a system. This gives rise to issues such as what is the response time of the system, does it crash, will it go with different software applications and platforms, can it hold so many hundreds and thousands of users, etc. This is when we set do load and performance testing.
6. What are the components of LoadRunner?
- The components of LoadRunner are The Virtual User Generator, Controller, and the Agent process, LoadRunner Analysis and Monitoring, LoadRunner Books Online.
7. What Component of LoadRunner would you use to record a Script?
- The Virtual User Generator (VuGen) component is used to record a script. It enables you to develop Vuser scripts for a variety of application types and communication protocols.
8. What Component of LoadRunner would you use to play Back the script. in multi user mode?
- The Controller component is used to playback the script. in multi-user mode. This is done during a scenario run where a vuser script. is executed by a number of vusers in a group.
9. What is a rendezvous point?
- You insert rendezvous points into Vuser scripts to emulate heavy user load on the server. Rendezvous points instruct Vusers to wait during test execution for multiple Vusers to arrive at a certain point, in order that they may simultaneously perform. a task. For example, to emulate peak load on the bank server, you can insert a rendezvous point instructing 100 Vusers to deposit cash into their accounts at the same time.
10. What is a scenario?
- A scenario defines the events that occur during each testing session. For example, a scenario defines and controls the number of users to emulate, the actions to be performed, and the machines on which the virtual users run their emulations.
11. Explain the recording mode for web Vuser script?
- We use VuGen to develop a Vuser script. by recording a user performing typical business processes on a client application. VuGen creates the script. by recording the activity between the client and the server. For example, in web based applications, VuGen monitors the client end of the database and traces all the requests sent to, and received from, the database server. We use VuGen to: Monitor the communication between the application and the server; Generate the required function calls; and Insert the generated function calls into a Vuser script.
12. Why do you create parameters?
- Parameters are like script. variables. They are used to vary input to the server and to emulate real users. Different sets of data are sent to the server each time the script. is run. Better simulate the usage model for more accurate testing from the Controller; one script. can emulate many different users on the system.
13. What is correlation?
Explain the difference between automatic correlation and manual correlation? - Correlation is used to obtain data which are unique for each run of the script. and which are generated by nested queries. Correlation provides the value to avoid errors arising out of duplicate values and also optimizing the code (to avoid nested queries). Automatic correlation is where we set some rules for correlation. It can be application server specific. Here values are replaced by data which are created by these rules. In manual correlation, the value we want to correlate is scanned and create correlation is used to correlate.
14. How do you find out where correlation is required? Give few examples from your projects?
- Two ways: First we can scan for correlations, and see the list of values which can be correlated. From this we can pick a value to be correlated. Secondly, we can record two scripts and compare them. We can look up the difference file to see for the values which needed to be correlated. In my project, there was a unique id developed for each customer, it was nothing but Insurance Number, it was generated automatically and it was sequential and this value was unique. I had to correlate this value, in order to avoid errors while running my script. I did using scan for correlation.
15. Where do you set automatic correlation options?
- Automatic correlation from web point of view can be set in recording options and correlation tab. Here we can enable correlation for the entire script. and choose either issue online messages or offline actions, where we can define rules for that correlation. Automatic correlation for database can be done using show output window and scan for correlation and picking the correlate query tab and choose which query value we want to correlate. If we know the specific value to be correlated, we just do create correlation for the value and specify how the value to be created.
16. What is a function to capture dynamic values in the web Vuser script?
- Web_reg_save_param function saves dynamic data information to a parameter.
17. When do you disable log in Virtual User Generator, When do you choose standard and extended logs?
- Once we debug our script. and verify that it is functional, we can enable logging for errors only. When we add a script. to a scenario, logging is automatically disabled. Standard Log Option: When you selectStandard log, it creates a standard log of functions and messages sent during script. execution to use for debugging. Disable this option for large load testing scenarios. When you copy a script. to a scenario, logging is automatically disabled Extended Log Option: Selectextended log to create an extended log, including warnings and other messages. Disable this option for large load testing scenarios. When you copy a script. to a scenario, logging is automatically disabled. We can specify which additional information should be added to the extended log using the Extended log options.
18. How do you debug a LoadRunner script?
- VuGen contains two options to help debug Vuser scripts-the Run Step by Step command and breakpoints. The Debug settings in the Options dialog box allow us to determine the extent of the trace to be performed during scenario execution. The debug information is written to the Output window. We can manually set the message class within your script. using the lr_set_debug_message function. This is useful if we want to receive debug information about a small section of the script. only.
19. How do you write user defined functions in LR?
Give me few functions you wrote in your previous project? - Before we create the User Defined functions we need to create the external library (DLL) with the function. We add this library to VuGen bin directory. Once the library is added then we assign user defined function as a parameter. The function should have the following format: __declspec (dllexport) char* (char*, char*)Examples of user defined functions are as follows:GetVersion, GetCurrentTime, GetPltform. are some of the user defined functions used in my earlier project.
20. What are the changes you can make in run-time settings?
- The Run Time Settings that we make are: a) Pacing - It has iteration count. b) Log - Under this we have Disable Logging Standard Log and c) Extended Think Time - In think time we have two options like Ignore think time and Replay think time. d) General - Under general tab we can set the vusers as process or as multithreading and whether each step as a transaction.
21. Where do you set Iteration for Vuser testing?
- We set Iterations in the Run Time Settings of the VuGen. The navigation for this is Run time settings, Pacing tab, set number of iterations.
22. How do you perform. functional testing under load?
- Functionality under load can be tested by running several Vusers concurrently. By increasing the amount of Vusers, we can determine how much load the server can sustain.
23. What is Ramp up? How do you set this?
- This option is used to gradually increase the amount of Vusers/load on the server. An initial value is set and a value to wait between intervals can bespecified. To set Ramp Up, go to ‘Scenario Scheduling Options’
24. What is the advantage of running the Vuser as thread?
- VuGen provides the facility to use multithreading. This enables more Vusers to be run per generator. If the Vuser is run as a process, the same driver program is loaded into memory for each Vuser, thus taking up a large amount of memory. This limits the number of Vusers that can be run on a single generator. If the Vuser is run as a thread, only one instance of the driver program is loaded into memory for the given number of Vusers (say 100). Each thread shares the memory of the parent driver program, thus enabling more Vusers to be run per generator.
25. If you want to stop the execution of your script. on error, how do you do that?
- The lr_abort function aborts the execution of a Vuser script. It instructs the Vuser to stop executing the Actions section, execute the vuser_end section and end the execution. This function is useful when you need to manually abort a script. execution as a result of a specific error condition. When you end a script. using this function, the Vuser is assigned the status “Stopped”. For this to take effect, we have to first uncheck the “Continue on error” option in Run-Time Settings.
26. What is the relation between Response Time and Throughput?
- The Throughput graph shows the amount of data in bytes that the Vusers received from the server in a second. When we compare this with the transaction response time, we will notice that as throughput decreased, the response time also decreased. Similarly, the peak throughput and highest response time would occur approximately at the same time.
27. Explain the Configuration of your systems?
- The configuration of our systems refers to that of the client machines on which we run the Vusers. The configuration of any client machine includes its hardware settings, memory, operating system, software applications, development tools, etc. This system component configuration should match with the overall system configuration that would include the network infrastructure, the web server, the database server, and any other components that go with this larger system so as to achieve the load testing objectives.
28. How do you identify the performance bottlenecks?
- Performance Bottlenecks can be detected by using monitors. These monitors might be application server monitors, web server monitors, database server monitors and network monitors. They help in finding out the troubled area in our scenario which causes increased response time. The measurements made are usually performance response time, throughput, hits/sec, network delay graphs, etc.
29. If web server, database and Network are all fine where could be the problem?
- The problem could be in the system itself or in the application server or in the code written for the application.
30. How did you find web server related issues?
- Using Web resource monitors we can find the performance of web servers. Using these monitors we can analyze throughput on the web server, number of hits per second that occurred during scenario, the number of http responses per second, the number of downloaded pages per second.
31. How did you find database related issues?
- By running “Database” monitor and help of “Data Resource Graph” we can find database related issues. E.g. You can specify the resource you want to measure on before running the controller and than you can see database related issues
32. Explain all the web recording options?
33. What is the difference between Overlay graph and Correlate graph?
- Overlay Graph: It overlay the content of two graphs that shares a common x-axis. Left Y-axis on the merged graph show’s the current graph’s value & Right Y-axis show the value of Y-axis of the graph that was merged. Correlate Graph: Plot the Y-axis of two graphs against each other. The active graph’s Y-axis becomes X-axis of merged graph. Y-axis of the graph that was merged becomes merged graph’s Y-axis.
34. How did you plan the Load? What are the Criteria?
- Load test is planned to decide the number of users, what kind of machines we are going to use and from where they are run. It is based on 2 important documents, Task Distribution Diagram and Transaction profile. Task Distribution Diagram gives us the information on number of users for a particular transaction and the time of the load. The peak usage and off-usage are decided from this Diagram. Transaction profile gives us the information about the transactions name and their priority levels with regard to the scenario we are deciding.
35. What does vuser_init action contain?
- Vuser_init action contains procedures to login to a server.
36. What does vuser_end action contain?
- Vuser_end section contains log off procedures.
37. What is think time? How do you change the threshold?
- Think time is the time that a real user waits between actions. Example: When a user receives data from a server, the user may wait several seconds to review the data before responding. This delay is known as the think time. Changing the Threshold: Threshold level is the level below which the recorded think time will be ignored. The default value is five (5) seconds. We can change the think time threshold in the Recording options of the Vugen.
38. What is the difference between standard log and extended log?
- The standard log sends a subset of functions and messages sent during script. execution to a log. The subset depends on the Vuser type Extended log sends a detailed script. execution messages to the output log. This is mainly used during debugging when we want information about: Parameter substitution. Data returned by the server. Advanced trace.
39. Explain the following functions:
- lr_debug_message - The lr_debug_message function sends a debug message to the output log when the specified message class is set. lr_output_message - The lr_output_message function sends notifications to the Controller Output window and the Vuser log file. lr_error_message - The lr_error_message function sends an error message to the LoadRunner Output window. lrd_stmt - The lrd_stmt function associates a character string (usually a SQL statement) with a cursor. This function sets a SQL statement to be processed. lrd_fetch - The lrd_fetch function fetches the next row from the result set.
40. Throughput
- If the throughput scales upward as time progresses and the number of Vusers increase, this indicates that the bandwidth is sufficient. If the graph were to remain relatively flat as the number of Vusers increased, it would be reasonable to conclude that the bandwidth is constraining the volume of data delivered.
41. Types of Goals in Goal-Oriented Scenario
- Load Runner provides you with five different types of goals in a goal oriented scenario:
* The number of concurrent Vusers
* The number of hits per second
* The number of transactions per second
* The number of pages per minute
* The transaction response time that you want your scenario
42. Analysis Scenario (Bottlenecks):
In Running Vuser graph correlated with the response time graph you can see that as the number of Vusers increases, the average response time of the check itinerary transaction very gradually increases. In other words, the average response time steadily increases as the load increases. At 56 Vusers, there is a sudden, sharp increase in the average response time. We say that the test broke the server. That is the mean time before failure (MTBF). The response time clearly began to degrade when there were more than 56 Vusers running simultaneously.
43. What is correlation?
Explain the difference between automatic correlation and manual correlation? - Correlation is used to obtain data which are unique for each run of the script. and which are generated by nested queries. Correlation provides the value to avoid errors arising out of duplicate values and also optimizing the code (to avoid nested queries). Automatic correlation is where we set some rules for correlation. It can be application server specific. Here values are replaced by data which are created by these rules. In manual correlation, the value we want to correlate is scanned and create correlation is used to correlate.
44. Where do you set automatic correlation options?
- Automatic correlation from web point of view, can be set in recording options and correlation tab. Here we can enable correlation for the entire script. and choose either issue online messages or offline actions, where we can define rules for that correlation. Automatic correlation for database, can be done using show output window and scan for correlation and picking the correlate query tab and choose which query value we want to correlate. If we know the specific value to be correlated, we just do create correlation for the value and specify how the value to be created.
45. What is a function to capture dynamic values in the web vuser script?
- Web_reg_save_param function saves dynamic data information to a parameter.
============================================================================================================================================
1.请问什么是性能测试、负载测试、压力测试？
原参考答案：
性能测试：对一个软件系统而言，包括执行效率、资源占用、系统稳定性、安全性兼容性、可扩展性等。
负载测试：通过逐步加压的方式来确定系统的处理能力，确定系统能承受的各项阀值。
压力测试：逐步增加负载，使系统某些资源达到饱和甚至失效的测试。
个人理解：
经典的问题，答案打算参考段念的书:
性能测试（Performance Testing）：是通过模拟系统实际运行的压力和使用场景组合，测试系统的性能是否满足实际生产的性能要求。
特点：1.主要目的是验证系统是否具备其宣称的能力
2.需要事先了解被测系统的典型场景，并具有确定的性能目标
3.要求在已确定的环境下运行
负载测试(Load Testing):通过在被测系统上不断增加压力，直到某个性能指标超过预定指标或者某种资源使用已经达到饱和状态
特点：1. 主要目的是找到系统处理能力的极限，为系统调优提供数据。测试形式/手段："检测--加压--知道性能指标超过预期"
2.在给定的测试环境下进行，考虑被测系统的业务压力量和典型场景
3. 一般用来了解系统的性能容量，或是配合性能调优
压力测试(Stress Testing)：测试系统在一定饱和状态下(CPU/MEMORY)，
特点：1. 主要目的是检查系统处于压力情况下时，应用的表现
2. 一般用于测试系统的稳定性
2.请分别针对性能测试、负载测试和压力测试试举一个简单的例子？
原参考答案：
性能测试例子：公司开发了一个小型项目管理系统，上线前需要做负载、压力、大数据量、强度测试等。
负载测试：逐步加压，从而得到“响应时间不超过10秒”，“服务器平均CPU利用率低于85%”等指标阀值。
压力测试：逐步加压，从而使“响应时间超过10秒”，“服务器平均CPU利用率高于90%”等指标来确定系统能承受的最大负载量。
3.请例举出常用的性能测试工具，并指出这些工具的优缺点？
LoadRunner，录制脚本快捷操作简便，需要一定的学习时间，有采购成本。
4.请问您是如何得到性能测试需求？怎样针对需求设计、分析是否达到需求？
在查看需求文档，从中提取性能测试需求，与用户交流，了解实际使用情况。
结合业务信息设计操作场景总结出需测试的性能关键指标。
执行用例后根据提取关键性能指标来分析是否满足性能需求。
5.什么时候可以开始执行性能测试？
在产品相对比较稳定，功能测试结束后。灵活性比较强。
6.什么是集合点？设置集合点有什么意义？LoadRunner中设置集合点的函数是哪个？
集合点可以控制各个Vuser以便在同一时刻执行任务。
借助集合点，可以再LoadRunner中实现真正意义上的并发。
lr_rendezvous()
7.性能测试时，是不是必须进行参数化？为什么要创建参数？LoadRunner中如何创建参数？
8是。
模拟用户真实的业务操作。
创建参数列表，用参数替换固定的文本。
8.您了解关联吗？如何找出哪里需要关联？请给一些您所在项目的实例。
了解。
使用LoadRunner自动关联功能。手动关联：录制两份相同操作步骤的脚本，找出不同的部分进行判断。
一个项目管理系统，每次登录后服务器都自动分配一个sessionID以便之后每次表单提交后验证。
9.您如何调试LoadRunner脚本？
设置断点、增加log。
10.在LoadRunner中如何编写自定义函数？请给出一个您在以前项目中编写的函数。
11.请问您是如何理解LoadRunner中集合点、事务以及检查点等概念？
集合点：可以控制各个Vuser以便在同一时刻执行任务，可实现真正意义上的并发。
事务：事务是用来度量服务器响应时间的操作集。
检查点：在回放脚本期间搜索特定内容，从而验证服务器响应内容的正确性。
12.如何应用LoadRunner进行性能测试？
使用虚拟用户生成器创建脚本，使用控制器设定场景、运行脚本，使用分析器分析运行后得到的数据。
13.LoadRunner中思考时间有什么作用？
用户执行两个连续操作期间等待的时间。模拟用户真实的使用情况。
14.LoadRunner中如何实现多用户并发操作，需要进行哪些设置？
设置集合点来实现，在脚本中加入lr_rendezvous()，然后可以在控制器中设定集结百分比。
15.LoadRunner中有基于目标和手动两种场景设计方式，他们分别适用于什么情况？
手动场景可按照要求来配置场景，能够更加精确的满足测试需要。
目标场景要先制定希望实现的测试目标，然后由控制器惊醒自动测试评估。
16.LoadRunner中有几种并发执行策略，它们的含义是什么？
三种。1.当所有虚拟用户中的x%到达集合点时释放。2.当所有正在运行的虚拟用户中的x%到达集合点时释放。3.当x个虚拟用户到达集合点时释放。
17.有5台配置为处理器：Intel Pentium 4 1.6G，内存容量 512MB，硬盘容量 40GB的机器，如何较好的利用这些机器完成一次并发用户数为1000人的性能测试工作？
1台做应用服务器，1台做数据库服务器，1台运行控制器并承担一部分负载生成任务，2台负载生成器。
18.平时大家在注册邮箱等关联操作时，经常会遇到需要输入验证码的情况，请问，如果我们公司也开发了一套带验证码的应用软件，需要警醒性能测试，您会如何处理？
留一个后门，我们设定一个所谓的“万能验证码”，只要用户输入这个“万能验证码”，系统就验证通过。测试完成后补上后门。
============================================================================================================================================
第二篇：性能测试面试题(参考第四篇的英文题目及答案)
1.什么是负载测试？什么是性能测试？
2.性能测试包含了哪些测试（至少举出3种）
3.简述性能测试的步骤
4.简述使用Loadrunner的步骤
5.什么时候可以开始执行性能测试？
6.LoadRunner由哪些部件组成？
7.你使用LoadRunner的哪个部件来录制脚本？
8.LoadRunner的哪个部件可以模拟多用户并发下回放脚本？
9.什么是集合点？设置集合点有什么意义?Loadrunner中设置集合点的函数是哪个?
10.什么是场景？场景的重要性有哪些?如何设置场景?
11.请解释一下如何录制web脚本？
12.为什么要创建参数?如何创建参数?
13.什么是关联？请解释一下自动关联和手动关联的不同。
14.你如何找出哪里需要关联？请给一些你所在项目的实例。
15.你在哪里设置自动关联选项？
16.哪个函数是用来截取虚拟用户脚本中的动态值？（手工管联）
17.你在VUGen中何时选择关闭日志？何时选择标准和扩展日志？
18.你如何调试LoadRunner脚本？
19你在LR中如何编写自定义函数？请给出一些你在以前进行的项目中编写的函数。
20.在运行设置下你能更改那些设置？
21.你在不同的环境下如何设置迭代？
22.你如何在负载测试模式下执行功能测试？
23.什么是逐步递增？你如何来设置？
24.以线程方式运行的虚拟用户有哪些优点？
25.当你需要在出错时停止执行脚本，你怎么做？
26.响应时间和吞吐量之间的关系是什么？
27.说明一下如何在LR中配置系统计数器？
28.你如何识别性能瓶颈？
29.如果web服务器、数据库以及网络都正常，问题会出在哪里？
30.如何发现web服务器的相关问题？
31.如何发现数据库的相关问题？
32.解释所有web录制配置？
33.解释一下覆盖图和关联图的区别？
34.你如何设计负载？标准是什么？
35.Vuser_init中包括什么内容？
36. Vuser_end中包括什么内容？
37.什么是think time？think_time有什么用？
38.标准日志和扩展日志的区别是什么？
39.解释以下函数及他们的不同之处。
Lr_debug_message
Lr_output_message
Lr_error_message
Lrd_stmt
Lrd_fetch
40.什么是吞吐量？
41.场景设置有哪几种方法
============================================================================================================================================
第三篇：性能测试面试题
1、 【测试理论】描述不同的角色（用户、产品开发人员、系统管理员）各自关注的软件性能要点。
2、 【测试理论】解释5个常用的性能指标的名称与具体含义。
3、 【测试流程】简述性能测试流程与各阶段的工作内容。
4、 【LR工具】web系统中，username参数表为file类型，表中有12个值，分别A、B、C、D、E、F、G、H、I、J、K、L。
测试场景中虚拟并发用户数设为4，迭代次数设为3，
参数中Select next row与Update value on分别为(Sequential, Each Iteration)与(Unique, Once)时，
写出迭代3次的取值情况。
（Select next row， Update value on） 虚拟用户取值（VUi：迭代时取值）
（Sequential， Each Iteration）
VU1：
VU2：
VU3：
VU4：
（Unique， Once）
VU1：
VU2：
VU3：
VU4：
5、【LR工具】web系统脚本录制过程中，两次录制同一功能点，在View Tree的Server Response中产生的字符串分别为：
Server Response：name="_id_Node " value=" RSDP0013425" />", ENDITEM,
Server Response：name="_id_Node " value=" RSDP1203655" />", ENDITEM,
为脚本回放成功，需要对字符串中某些字符做一定处理，写出详细实现方法。
6、 【数据库应用】现有Customers表和Sales表的数据如下：
Customers表：
CustID Name ShpCity Discount
449320 Adapto PortLand 0.05
890003 AA PortLand 0.05
888402 Seaworth Albany 0.04
Sales表：
SaleID CustID SaleMount
234112 499320 8000
234113 888402 6500
234114 499320 5900
234115 890003 4500
要求：
1） 给出查询语句，描述：在Customers表中查询名字为AA或Bolt的查询语句；
2） 给出删除操作，描述：在Sales表中删除SaleID为234115的语句。
3） 根据以下结果表给出多表查询语句。
SaleID CustID Name Discount SaleMount
234112 499320 Adapto 0.05 8000
234113 888402 Seaworth 0.04 6500
234114 499320 Adapto 0.05 5900
234115 890003 AA 0.05 4500
7、 【数据库应用】为了尽可能避免大表全表扫描，最常见的方法有哪些？
8、 【中间件】WebLogic参数调整中，列举三项影响并发性能的参数项并简述其含义。
9、 【Unix命令】HP-UX与AIX操作系统中，监控CPU、内存、磁盘I/O的命令分别是什么？
10、 【Unix命令】用命令实现：
1） 对文件FileA添加读、写、执行权限；
2） 列出当前系统与java相关的活动进程；
3） 搜索当前文件夹中所有的.sh文件。
11、 【网络】服务器ip地址为128.64.96.100，HP-UX操作系统，ftp服务开启，用户名与密码分别为username/password, /home目录下有一个monitor.svc文件，现需要将monitor.svc文件取到客户机192.168.2.100，服务器与客户机二者之间网络互通，描述在192.168.2.100上操作过程
============================================================================================================================================
第四篇： 45道性能测试的面试题及答案（In English）
1. What is load testing?
- Load testing is to test that if the application works fine with the loads that result from large number of simultaneous users, transactions and to determine weather it can handle peak usage periods.
2. 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.
3. Did u use LoadRunner? What version?
- Yes. Version x.x .
4. Explain the Load testing process? -
Step 1: Planning the test. Here, we develop a clearly defined test plan to ensure the test scenarios we develop will accomplish load-testing objectives.
Step 2: Creating Vusers. Here, we create Vuser scripts that contain tasks performed by each Vuser, tasks performed by Vusers as a whole, and tasks measured as transactions.
Step 3: Creating the scenario. A scenario describes the events that occur during a testing session. It includes a list of machines, scripts, and Vusers that run during the scenario. We create scenarios using LoadRunner Controller. We can create manual scenarios as well as goal-oriented scenarios. In manual scenarios, we define the number of Vusers, the load generator machines, and percentage of Vusers to be assigned to each script. For web tests, we may create a goal-oriented scenario where we define the goal that our test has to achieve. LoadRunner automatically builds a scenario for us.
Step 4: Running the scenario.We emulate load on the server by instructing multiple Vusers to perform. tasks simultaneously. Before the testing, we set the scenario configuration and scheduling. We can run the entire scenario, Vuser groups, or individual Vusers.
Step 5: Monitoring the scenario.We monitor scenario execution using the LoadRunner online runtime, transaction, system resource, Web resource, Web server resource, Web application server resource, database server resource, network delay, streaming media resource, firewall server resource, ERP server resource, and Java performance monitors.
Step 6: Analyzing test results. During scenario execution, LoadRunner records the performance of the application under different loads. We use LoadRunner’s graphs and reports to analyze the application’s performance.
5. When do you do load and performance Testing?
- We perform. load testing once we are done with interface (GUI) testing. Modern system architectures are large and complex. Whereas single user testing primarily on functionality and user interface of a system component, application testing focuses on performance and reliability of an entire system. For example, a typical application-testing scenario might depict 1000 users logging in simultaneously to a system. This gives rise to issues such as what is the response time of the system, does it crash, will it go with different software applications and platforms, can it hold so many hundreds and thousands of users, etc. This is when we set do load and performance testing.
6. What are the components of LoadRunner?
- The components of LoadRunner are The Virtual User Generator, Controller, and the Agent process, LoadRunner Analysis and Monitoring, LoadRunner Books Online.
7. What Component of LoadRunner would you use to record a Script?
- The Virtual User Generator (VuGen) component is used to record a script. It enables you to develop Vuser scripts for a variety of application types and communication protocols.
8. What Component of LoadRunner would you use to play Back the script. in multi user mode?
- The Controller component is used to playback the script. in multi-user mode. This is done during a scenario run where a vuser script. is executed by a number of vusers in a group.
9. What is a rendezvous point?
- You insert rendezvous points into Vuser scripts to emulate heavy user load on the server. Rendezvous points instruct Vusers to wait during test execution for multiple Vusers to arrive at a certain point, in order that they may simultaneously perform. a task. For example, to emulate peak load on the bank server, you can insert a rendezvous point instructing 100 Vusers to deposit cash into their accounts at the same time.
10. What is a scenario?
- A scenario defines the events that occur during each testing session. For example, a scenario defines and controls the number of users to emulate, the actions to be performed, and the machines on which the virtual users run their emulations.
11. Explain the recording mode for web Vuser script?
- We use VuGen to develop a Vuser script. by recording a user performing typical business processes on a client application. VuGen creates the script. by recording the activity between the client and the server. For example, in web based applications, VuGen monitors the client end of the database and traces all the requests sent to, and received from, the database server. We use VuGen to: Monitor the communication between the application and the server; Generate the required function calls; and Insert the generated function calls into a Vuser script.
12. Why do you create parameters?
- Parameters are like script. variables. They are used to vary input to the server and to emulate real users. Different sets of data are sent to the server each time the script. is run. Better simulate the usage model for more accurate testing from the Controller; one script. can emulate many different users on the system.
13. What is correlation?
Explain the difference between automatic correlation and manual correlation? - Correlation is used to obtain data which are unique for each run of the script. and which are generated by nested queries. Correlation provides the value to avoid errors arising out of duplicate values and also optimizing the code (to avoid nested queries). Automatic correlation is where we set some rules for correlation. It can be application server specific. Here values are replaced by data which are created by these rules. In manual correlation, the value we want to correlate is scanned and create correlation is used to correlate.
14. How do you find out where correlation is required? Give few examples from your projects?
- Two ways: First we can scan for correlations, and see the list of values which can be correlated. From this we can pick a value to be correlated. Secondly, we can record two scripts and compare them. We can look up the difference file to see for the values which needed to be correlated. In my project, there was a unique id developed for each customer, it was nothing but Insurance Number, it was generated automatically and it was sequential and this value was unique. I had to correlate this value, in order to avoid errors while running my script. I did using scan for correlation.
15. Where do you set automatic correlation options?
- Automatic correlation from web point of view can be set in recording options and correlation tab. Here we can enable correlation for the entire script. and choose either issue online messages or offline actions, where we can define rules for that correlation. Automatic correlation for database can be done using show output window and scan for correlation and picking the correlate query tab and choose which query value we want to correlate. If we know the specific value to be correlated, we just do create correlation for the value and specify how the value to be created.
16. What is a function to capture dynamic values in the web Vuser script?
- Web_reg_save_param function saves dynamic data information to a parameter.
17. When do you disable log in Virtual User Generator, When do you choose standard and extended logs?
- Once we debug our script. and verify that it is functional, we can enable logging for errors only. When we add a script. to a scenario, logging is automatically disabled. Standard Log Option: When you selectStandard log, it creates a standard log of functions and messages sent during script. execution to use for debugging. Disable this option for large load testing scenarios. When you copy a script. to a scenario, logging is automatically disabled Extended Log Option: Selectextended log to create an extended log, including warnings and other messages. Disable this option for large load testing scenarios. When you copy a script. to a scenario, logging is automatically disabled. We can specify which additional information should be added to the extended log using the Extended log options.
18. How do you debug a LoadRunner script?
- VuGen contains two options to help debug Vuser scripts-the Run Step by Step command and breakpoints. The Debug settings in the Options dialog box allow us to determine the extent of the trace to be performed during scenario execution. The debug information is written to the Output window. We can manually set the message class within your script. using the lr_set_debug_message function. This is useful if we want to receive debug information about a small section of the script. only.
19. How do you write user defined functions in LR?
Give me few functions you wrote in your previous project? - Before we create the User Defined functions we need to create the external library (DLL) with the function. We add this library to VuGen bin directory. Once the library is added then we assign user defined function as a parameter. The function should have the following format: __declspec (dllexport) char* (char*, char*)Examples of user defined functions are as follows:GetVersion, GetCurrentTime, GetPltform. are some of the user defined functions used in my earlier project.
20. What are the changes you can make in run-time settings?
- The Run Time Settings that we make are: a) Pacing - It has iteration count. b) Log - Under this we have Disable Logging Standard Log and c) Extended Think Time - In think time we have two options like Ignore think time and Replay think time. d) General - Under general tab we can set the vusers as process or as multithreading and whether each step as a transaction.
21. Where do you set Iteration for Vuser testing?
- We set Iterations in the Run Time Settings of the VuGen. The navigation for this is Run time settings, Pacing tab, set number of iterations.
22. How do you perform. functional testing under load?
- Functionality under load can be tested by running several Vusers concurrently. By increasing the amount of Vusers, we can determine how much load the server can sustain.
23. What is Ramp up? How do you set this?
- This option is used to gradually increase the amount of Vusers/load on the server. An initial value is set and a value to wait between intervals can bespecified. To set Ramp Up, go to ‘Scenario Scheduling Options’
24. What is the advantage of running the Vuser as thread?
- VuGen provides the facility to use multithreading. This enables more Vusers to be run per generator. If the Vuser is run as a process, the same driver program is loaded into memory for each Vuser, thus taking up a large amount of memory. This limits the number of Vusers that can be run on a single generator. If the Vuser is run as a thread, only one instance of the driver program is loaded into memory for the given number of Vusers (say 100). Each thread shares the memory of the parent driver program, thus enabling more Vusers to be run per generator.
25. If you want to stop the execution of your script. on error, how do you do that?
- The lr_abort function aborts the execution of a Vuser script. It instructs the Vuser to stop executing the Actions section, execute the vuser_end section and end the execution. This function is useful when you need to manually abort a script. execution as a result of a specific error condition. When you end a script. using this function, the Vuser is assigned the status “Stopped”. For this to take effect, we have to first uncheck the “Continue on error” option in Run-Time Settings.
26. What is the relation between Response Time and Throughput?
- The Throughput graph shows the amount of data in bytes that the Vusers received from the server in a second. When we compare this with the transaction response time, we will notice that as throughput decreased, the response time also decreased. Similarly, the peak throughput and highest response time would occur approximately at the same time.
27. Explain the Configuration of your systems?
- The configuration of our systems refers to that of the client machines on which we run the Vusers. The configuration of any client machine includes its hardware settings, memory, operating system, software applications, development tools, etc. This system component configuration should match with the overall system configuration that would include the network infrastructure, the web server, the database server, and any other components that go with this larger system so as to achieve the load testing objectives.
28. How do you identify the performance bottlenecks?
- Performance Bottlenecks can be detected by using monitors. These monitors might be application server monitors, web server monitors, database server monitors and network monitors. They help in finding out the troubled area in our scenario which causes increased response time. The measurements made are usually performance response time, throughput, hits/sec, network delay graphs, etc.
29. If web server, database and Network are all fine where could be the problem?
- The problem could be in the system itself or in the application server or in the code written for the application.
30. How did you find web server related issues?
- Using Web resource monitors we can find the performance of web servers. Using these monitors we can analyze throughput on the web server, number of hits per second that occurred during scenario, the number of http responses per second, the number of downloaded pages per second.
31. How did you find database related issues?
- By running “Database” monitor and help of “Data Resource Graph” we can find database related issues. E.g. You can specify the resource you want to measure on before running the controller and than you can see database related issues
32. Explain all the web recording options?
33. What is the difference between Overlay graph and Correlate graph?
- Overlay Graph: It overlay the content of two graphs that shares a common x-axis. Left Y-axis on the merged graph show’s the current graph’s value & Right Y-axis show the value of Y-axis of the graph that was merged. Correlate Graph: Plot the Y-axis of two graphs against each other. The active graph’s Y-axis becomes X-axis of merged graph. Y-axis of the graph that was merged becomes merged graph’s Y-axis.
34. How did you plan the Load? What are the Criteria?
- Load test is planned to decide the number of users, what kind of machines we are going to use and from where they are run. It is based on 2 important documents, Task Distribution Diagram and Transaction profile. Task Distribution Diagram gives us the information on number of users for a particular transaction and the time of the load. The peak usage and off-usage are decided from this Diagram. Transaction profile gives us the information about the transactions name and their priority levels with regard to the scenario we are deciding.
35. What does vuser_init action contain?
- Vuser_init action contains procedures to login to a server.
36. What does vuser_end action contain?
- Vuser_end section contains log off procedures.
37. What is think time? How do you change the threshold?
- Think time is the time that a real user waits between actions. Example: When a user receives data from a server, the user may wait several seconds to review the data before responding. This delay is known as the think time. Changing the Threshold: Threshold level is the level below which the recorded think time will be ignored. The default value is five (5) seconds. We can change the think time threshold in the Recording options of the Vugen.
38. What is the difference between standard log and extended log?
- The standard log sends a subset of functions and messages sent during script. execution to a log. The subset depends on the Vuser type Extended log sends a detailed script. execution messages to the output log. This is mainly used during debugging when we want information about: Parameter substitution. Data returned by the server. Advanced trace.
39. Explain the following functions:
- lr_debug_message - The lr_debug_message function sends a debug message to the output log when the specified message class is set. lr_output_message - The lr_output_message function sends notifications to the Controller Output window and the Vuser log file. lr_error_message - The lr_error_message function sends an error message to the LoadRunner Output window. lrd_stmt - The lrd_stmt function associates a character string (usually a SQL statement) with a cursor. This function sets a SQL statement to be processed. lrd_fetch - The lrd_fetch function fetches the next row from the result set.
40. Throughput
- If the throughput scales upward as time progresses and the number of Vusers increase, this indicates that the bandwidth is sufficient. If the graph were to remain relatively flat as the number of Vusers increased, it would be reasonable to conclude that the bandwidth is constraining the volume of data delivered.
41. Types of Goals in Goal-Oriented Scenario
- Load Runner provides you with five different types of goals in a goal oriented scenario:
* The number of concurrent Vusers
* The number of hits per second
* The number of transactions per second
* The number of pages per minute
* The transaction response time that you want your scenario
42. Analysis Scenario (Bottlenecks):
In Running Vuser graph correlated with the response time graph you can see that as the number of Vusers increases, the average response time of the check itinerary transaction very gradually increases. In other words, the average response time steadily increases as the load increases. At 56 Vusers, there is a sudden, sharp increase in the average response time. We say that the test broke the server. That is the mean time before failure (MTBF). The response time clearly began to degrade when there were more than 56 Vusers running simultaneously.
43. What is correlation?
Explain the difference between automatic correlation and manual correlation? - Correlation is used to obtain data which are unique for each run of the script. and which are generated by nested queries. Correlation provides the value to avoid errors arising out of duplicate values and also optimizing the code (to avoid nested queries). Automatic correlation is where we set some rules for correlation. It can be application server specific. Here values are replaced by data which are created by these rules. In manual correlation, the value we want to correlate is scanned and create correlation is used to correlate.
44. Where do you set automatic correlation options?
- Automatic correlation from web point of view, can be set in recording options and correlation tab. Here we can enable correlation for the entire script. and choose either issue online messages or offline actions, where we can define rules for that correlation. Automatic correlation for database, can be done using show output window and scan for correlation and picking the correlate query tab and choose which query value we want to correlate. If we know the specific value to be correlated, we just do create correlation for the value and specify how the value to be created.
45. What is a function to capture dynamic values in the web vuser script?
- Web_reg_save_param function saves dynamic data information to a parameter.
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