45 个LoadRunner英文面试笔试问题附答案2文档格式.docx

1、 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 graduall

2、y increase the amount of Vusers/load on the server. An initial value is set an d a value to wait between intervals can be specified. 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 en

3、ables 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 instan

4、ce 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 fun

5、ction aborts the execution of a Vuser script. It instructs the Vuser to stop executing the Actions section, execute the vuser_end section an d 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 scrip

6、t 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 an d Throughput? - The Throughput graph shows the amount of data in bytes that the Vuse

7、rs 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 an d highest response time would occur approximately at the same time. 27、Explain the Config

8、uration 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 configu

9、ration should match with the overall system configuration that would include the network infrastructure, the web server, the database server, an d 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? -

10、Performance Bottlenecks can be detected by using monitors. These monitors might be application server monitors, web server monitors, database server monitors an d network monitors. They help in finding out the troubled area in our scenario which causes increased response time. The measurements made

11、are usually performance response time, throughput, hits/sec, network delay graphs, etc. 29、If web server, database an d 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

12、 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 page

13、s per second. 31、How did you find database related issues? - By running Database monitor an d 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 an d than you can see database related issues 32、Expla

14、in all the web recording options? 33、What is the difference between Overlay graph an d 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 gra

15、ph 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 th

16、e number of users, what kind of machines we are going to use an d from where they are run. It is based on 2 important documents, Task Distribution Diagram an d Transaction profile. Task Distribution Diagram gives us the information on number of users for a particular transaction an d the time of the

17、 load. The peak usage an d off-usage are decided from this Diagram. Transaction profile gives us the information about the transactions name an d their priority levels with regard to the scenario we are deciding. 35、What does vuser_init action contain? - Vuser_init action contains procedures to logi

18、n 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

19、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

20、 Vugen. 38、What is the difference between stan dard log an d extended log? - The stan dard log sends a subset of functions an d 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 main

21、ly 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_out

22、put_message - The lr_output_message function sends notifications to the Controller Output window an d 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

23、 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 an d the number of Vusers increase, this indicates that the ban dwidth is

24、 sufficient. If the graph were to remain relatively flat as the number of Vusers increased, it would be reasonable to conclude that the ban dwidth 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

25、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 res

26、ponse 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 avera

27、ge 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 an d manual correl

28、ation?- Correlation is used to obtain data which are unique for each run of the script an d which are generated by nested queries. Correlation provides the value to avoid errors arising out of duplicate values an d also optimizing the code （to avoid nested queries）. Automatic correlation is where we

29、 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 an d create correlation is used to correlate. 44、Where do you set automatic correlation options?

30、 - Automatic correlation from web point of view, can be set in recording options an d correlation tab. Here we can enable correlation for the entire script an d choose either issue online messages or offline actions, where we can define rules for that correlation. Automatic correlation for database,

31、 can be done using show output window an d scan for correlation an d picking the correlate query tab an d 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 an d 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.