Load Runner is Performance Testing Tool, which is Mercury product, to know more about the testing tools pls click here
1.What is load testing?
Load testing is to test that the application works with the loads that results from large number of simultaneous users , transactions and to determine whether it can handle peak usage periods.
2. What is performance testing?
Timing for both read and update transaction should be gathered to determine whether system functions or being performed in an acceptable time frame. 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. Explain the load testing process?
Step1: Planning the test: Here, we develop a clearly defined test plan to ensure the test scenarios we develop will accomplish load testing objectives.
Step2: Creating Vusers: Here, we create Vuser scripts that contain tasks performed by each Vusers, tasks performed by Vusers as whole, and tasks measured as transactions.
step3: Creating the scenario: A scenario describes the events that occurred during the testing session.It includes a list of machines scripts and Vusers that run during the scenario. We create scenarios using load runner controller. We can create manual scenarios as well as goal oriented scenarios. In manual scenarios, we defined the number of Vusers, the load generated 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. Load runner automatically builds a scenarios for us.
step4: 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.
Step5: Monitoring the scenario: We monitor scenario execution using the load runner online run time 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
Step6: Analyzing the Test results: During the scenario execution LR records the performance of the application under different loads. We use load runner’s graphs and reports to analyze the application performance.
4. 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 Ex: A typical application testing scenario might depict 1000 users login 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 application and platform, can it hold so many 100’s and 1000’s of users etc.. This is when we set to do load and performance testing.
5. What are the components of load runner?
The components of load runner are the virtual user generator, controller, the agent process, load runner analysis and monitoring, load runner books online.
6. What component of load runner would you use to record a script?
The Virtual user generator (VuGen) component is used to record a script. It enable you to develop Vuser scripts for a variety of application types and communication protocols.
7. What component of Load runner would you use to playback the script in multi user mode?
The controller component is used to playback the script in multiuser mode. This is done during the scenario run where a Vuser script is executed by number of Vusers in a group.
8. What is a rendezvous point?
You insert rendezvous point into Vuser scripts to emulate heavy user load on the server. Rendezvous point instructs Vusers to wait during the test execution for multiple Vusers to arrive at certain point, in order that they may simultaneously perform a task. for Ex. 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.
9. What is a Scenario?
A Scenario defines the events that occur during each testing sessions. For example a scenario defines and controls the number of user to emulate, the actions to be performed, and the machines on which the virtual users run their emulations.
10. Explain the recording mode for Web Vuser Script?
We use VuGen to develop a Vuser script by recording a user performing typical business process on a client application. VuGen creates a script by recording the activity between the client and server. For example, in web based application, VuGen monitors the client end of database and traces all the request sent to, and receive the database server. We use VuGen to monitor the communication between the application and server, Generates the required function calls and insert the generated function calls into a Vuser script
11.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.
12. what is co-relation? Explain the different between automatic Co-relation and Manual co-relation?
Co-relation is used to obtained data which are unique for each run of the script and which are generated by nested queries. Co-relation provides the value to avoid errors arising out of duplicate values and also optimizing the code (to avoid nested queries). Automated Co-relation is where we set some rules for co-relation. It can be application server specific. Here values are replaced by data, which are created by these rules. In manual co-relation the value we want to correlate is scanned and create co-relation is used to co-relate
13. How do you find out where co-relation is required? Give few example 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 correlate.
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.
14. 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 the 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 correlate, we just do create correlation for values and specify how the value to be created.
15. What is the function to capture dynamic value in the web Vuser script?
Web_reg_save_param function saves dynamic data information to a parameter.
16. When do you disable login Virtual User Generator, when do you choose standard and extended logs?
Once we debug script and verify that it is functional, we can enable login for errors only. When we add a script to a scenario, logging is automatically disabled
Standard log option: When you select standard log it creates a standard log off functions and messages sent during script execution to use for debugging. Disable this option for large Load test scenarios when you copy a script to a scenario logging is automatically disabled.
Extended log option: Select extended log to create and extended log, including warning 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.
17. How do you debug a load runner script?
VuGen contains two options to help debug Vuser scripts-the run step by step command and break points.The debug settings in the options dialog box allow us to determine the extend of the trace to be performed during the 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.
18. How do you write user defined fuctions in Load runner? Give me few functions you wrote in your previous project?
Before we create the user defined function 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 parameter. The function should have the following format: _declspec(dllexport) char * < function name > (char*, char*) Examples of the user defined functions are as follows: Get Version Get Current Time, Getpltform are some of the user defined functions used in my earlier project.
19. What are the changes you can make in runtime settings?
The runtime settings that we make are
1)Pacing: It has iteration count.
2)Log: Under this we have disabled logging standard log
3)Extended think time: In think time we have two options like ignore think time and replay think time.
4)General: under general tab we can set the Vusers as process or as multi threading and whether each step as transaction.
20. Where do you set iteration for Vuser testing?
We set iteration in the run time settings of the VuGen. The navigation for this is runtime setting, phasing tab, set number of iterations.
21.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.
22. 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 vlaue to wait between intervals can be specified. To set Ramp-up, go to “Scenario Scheduling Options”.
23. 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, the only one instance of 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.
24. 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 sections, 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 a status “stopped”. For this to take effect we have to first uncheck the “continue on error” option in runtime setting.
25. What is the relation between response time and throughput?
The throughput graph shows the amount of data in bites 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.
26. Explain the configuration of your system?
The configuration of your system 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. 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 low testing objectives.
27. How do you identify the performance bottlenecks?
Performance bottleneck can be detected by using monitors. these monitors might me application server monitors, web server monitors, database server monitors and network monitor . 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 /second, network delay graphs etc..
28. 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.
29. how do 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 /second that occurred during scenario, the number of hit responses per second the number of download pages per sec.
30. how did you find the database related issues?
By running database monitor and help of data resource graph we can find database related issues. Example, you can specify the resource you want to measure on before running the controller and then you can see database related issues.
31.What is the differences 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 shows the current graphs value and 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 Y axis becomes X axis of merged graph. Y axis of the graph that was merged becomes merged graphs Y axis.
32. How did you planned 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 two 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 of usage are decided from this diagram. transaction profile gives us the information about the transaction names and their priorities levels with regard to the scenario we are deciding.
33. What does Vuser_init action contains?
Vuser_init action contains procedures to login to a server
34. What does Vuser_end action contain?
It contains logoff procedures.
35. What is think time? How does you change the threshold?
Think time is the time that a real user waits between actions. Ex: When a user receives data from a server, the user may wait serveral seconds to review the data before resposding. 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 5 seconds. We can change the think time threshold in the recording options of the VuGen.
36.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.
37. Explain the following functions
lr_debug_message - the lr_debug_message function sends a debug message to the out put log when the specified message class is set.
lr_output_message - this function sends notification to the controller output window and the Vuser log file.
lr_error_message - this function sends an error message ti the load runner output window.
lrd_stmt- this function associates a character string ( usually a sql statement) with a courser.
this function sets a sql statement to be processed.
lrd_fetch - this function fetches th next row from the result set.
Throughput- if the thruoghput scales upword as time progresses and number of Vusers incraesed, this indecates 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.
38.Types of goals in goal oriented scenario
Load runner provides u with 5 different types of goals in goal oriented scenario:
The no. of concurrent Vusers
The no. of hits per second
The no. of transactions per second
The no. of pages per minute
The transaction response time that you want your scenario
39Analysis scenario(bottlenecks):
In running Vuser graph correlated with the response time graph you can see that as no. 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 increases 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.
40.What is running virtual user graph?
It displays the number of Vusers that execute vuser script during each second of the scenario run. Only running and rendezvous state are include(loading, ready and pause are not displayed).
41.What protocol does LR supports?
Industry slandered protocols .For EX: HTTP and ODBC are explicitly supported by LR. Further more any protocol that communicates over a windows socket can be supported.
42. What do i need to know to do load testing in addition to knowing how to use the LR tool?
In addition to knowing the tool:
-management aspects of load testing, planning being paramount
-requirements gathering, profile/mix,SLA,acceptance criteria
-an general understanding of the protocol yo are working with, developers can be unhealpfull
-a basic understanding of c programming
-know that you will be working wit demising time scales and you are really at the end of the life cycle
-as a result of the above you may have to work unsociable covers including week ends
- managers and other “Powers that be”-”BOX tickers” will not understand your plight
You need to be able to communicate effectively at all levels wit different departments from business to Dev to system testing
-voice your problems as soon as possible- planning
-fail to plan - plan to fail
43.What can i monitor with LR?
Monitor system bottle necks during a test run can capture and display the performance data from every server or component.
44.How many users can i emulate with LR on a pc?
Unlimited, no dead end.
Depends on system response. That to in turn depend on various factors like entire system configuration etc.
If system bottleneck observes in very beginning or minimum number of Vusers no further addition of Vusers will be considered unless observed bottle neck is resolved.
45.What r the Vuser comp[components in the LR?
Application components used are client, data base or additionally business application server
Web server works on and through LAN, WAN or WWW. connection.
Application server components are client, business server and data base server without use of www but through protocols like ftp.
46. What is running virtual user graph?
It displays the number of Vusers that execute vuser script during each second of the scenario run. Only running and rendezvous state are include(loading, ready and pause are not displayed).
47.What are the reasons why parameterization is necessary when load testing the web server and the data base server?
Parameterization is generally done to test with multiple set of data or records.
48. What is LR?
LR accurately measure and analysis the system performance and functionality .
49. When LR is used?
When multiple users were work concurrently
50.What is the advantage of using LR?
1. LR automatically records the performance of the client server during test.
2. LR ckecks where performance delauys occure netwoerk client delays.
3. LR monitor the network and server resource to help the improve performance.
51How you load a loadrunner agent?
Controller instruct the remote command launcher to launch the agent.
52. how many types of Vusers are available?
There are several types of Vusers
1. GUI
2. Database
3.RTE(Terminal emulator)
4. SAP
5. DCOME
6. Peoplesoft
7. Java
8. BAAN
53. What is GUI Vuser and on which platform it will run?
GUI vuser operate graphical user interface application and it can run in either the MS windows or X windows environment.
54. What is loadrunner API function?
Database Vuser do not operate client application. Using loadrunner API function the database Vuser can access data from the server.
55. how do develop the database Vuser script?
Developing the database Vuser script either by recording with load runner Vuser script generator (VuGen) or by using loadrunner Vuser script template.
56. How many sections database Vuser script have?
3 sections, written in code that assemble in C, SQL call to the database, written in TSL (test script language).
57. How you enhance the basic script?
By adding control flow, structure, by inserting transaction point and rendezvous point, adding functions.
58. What is runtime setting?
Runtime setting includes loop.log and timing information.
59. What is standalone mode?
To verify that the script runs correctly or not.
60. What type of function generate and insert by the VuGen to the script whe you record a script?
1. LR function (Vuser function)
2. Protocol function.
61. What is LR function?
Obtain the information about Vuser running in a scenario.
62 What is protocol function?
Obtain the information about the type of Vuser.
63. what are the section contained by the VuGen while creating a Vuser script?
VuGen contains the 3 sections.
1. Vuser-init
2. Action
3. Vuser-End
64. What is Vuser-init section?
Record your log into the server(Vuser initialize loaded)
65. What is action section?
Record the client activity
66. What is Vuser end section?
Record a log off into the server(Vuser stopped)
67.What is the Vuser in the Scenario?
Loadrunner replace the human user with Vuser.
68. What is host?
Host is machine which execute the Vuser script.
69. What are the load runner testing process?
There are five steps:
1. Planning the test.
2. Creating the Vuser script.
3. Creating the scenario.
4. Running the scanario.
5. Analysis the test result.
70. What is planning for test?
Define the performance testing requirements, for ex: Number of concurrent users, typical business processess and required response time.
81. What do you mean by creating Vuser script?
Creating Vuser script for emulate the action that virtual user perform during the scenario execution.
82. What are the processes for developing a Vuser script?
There are 5 steps for developing a Vuser script.
1. recording the Vuser script.
2. Edit the Vuser script.
3. runtime settings.
4. Run the vuser script in standalone mode.
5. Incorporate the Vuser script into a load runner scenario
83. How to create a scenario?
We have to install load runner controller to the host. then we include list of hosts (where Vuser script execute) then the list of Vuser script ( where Vuser run) and then list of vuser that run during the scenario.
84. What do you mean by remote command launcher?
RCL enables the controller to start the application on the host machine.
85. What is loadrunner agent?
Agent is interface between host machine and controller.
86.What is report viewer?
Each report viewer contains the report header and report viewer tool bar.
87.. What is Vuser script?
While run a scenario every Vuser execute a script that is known as Vuser script.
88. What the vuser script contain?
The Vuser script includes the function that measure and record the performance of the server during the scenario.
89.. What is transaction?
Transaction measures time, which takes for the server to respond to task submitted my Vuser.
90. What is rendezvous point?
To emulate peak load on the srever.
91. When the rendezvous point is inserted?
when multiple Vuser to perform tasks at exactly the same time then insert the rendezvous point to emulate the peak load on server.
92. What is report header and what are the information contains?
It display general scenario information and it contains the information like title, scenario, result start time, end time and duration.
93. What is rendezvous graph?
It indicate when Vuser were released from rendezvous point and how many Vuser are released from each point. It help the transaction performance time.
94. What is transaction per second graph(PASS)?
It display the number of completed, successful transactions performed during each second of scenario run.
95. What is percentile graph?
The percentage of transaction that were performed within a given time range.
96. What is transaction performance graph?
Displays the average time taken to perform transaction during each second of the scenario run.
97. What are types of correlation?
Manual and Automation co-relation
Manual correlation: correlation is used to obtain data which are unique for each run of the script and which are generated by nested queries.
Automation correlation: It 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.
98. What is load runner controller?
Controller is managed and maintain the scenario. Using controller you control all the vuser in single work station.
99.How VuGen create a Vuser script?
By recording the activity between client and server
100. how you edit the script?
While editing the script we have to insert the transaction point and rendezvous point.
101. When a scenario run a exactly, what happens?
1. the controller checks the scenario configuration information.
2. Then next it invoke the application that you select to run with the scenario.
3. Then transform each script to its related hosts, when the vuser are ready they start execution.
102. How to run a scenario?
Open an existing scenario
Configure the scenario
set the result directory
Run the scenario
103. What is the load runner start transaction and its syntax?
It will start the transaction on the script.
Syntax: Lr-start-transaction(”transaction name”)
104. What is the load runner end transaction and its syntax?
It will end transaction.
Syntax: Lr-end-transaction(”transaction name”, LR-AUTO)
105. Where you insert the rendezvous point?
Rendezvous point inserted into script to calculate the peak load of the server.
Syntax: lr-rendezvous(”rendezvous point”)
106. What are the elements in the load runner controller?
Title bar ( Name of the scenario presently working). Menu bar ( selecting the various command ). Tool bar. status bar.
107. What are the 5 icons appear in the bottom of the controller windows?
1. Host windows (list of machines)
2. Script windows (list of all the vuser script)
3. Rendezvous windows
4. Transaction windows(display all the transactions )
5. output window(Display error and notification message)
108. What is .lrs?
Loadrunner save the information in a scenario files.
109. What is scenario wizard?
Through scenario wizard we can create a new scenario.
110. What is filtering and sorting?
We can filter the information display only those items that meet the selected criteria(filter box) exam you can filter Vuser only those who are in ready state.
Sorting we can sort all the Vuser in the vuser list. In order to their vuser ID(1,2,3,4,5,6,7,8,9).
111. What are the information creating for each host?
1. The status of the host.
2. The platform type of the host(window/unix)
3 Details of the scenario.
112. How to create a host list for a scenario?
1.Install remote command launcher on every machine.
2. Add the name of the host to the host lists.
3. Set attributes for each host.
4. Select which hosts will take part in the scenario.
113. What the host attributes determine?
1. The maximum number of vuser that host can run.
2. The initialization quota.
3. The location of the winrunner configuration file.
4. The location of the file during runtime.
114. How you set maximum number of vuser that a host can run?
We can modify the maximum number of Vuser according to the (available resource, the needs of yours scenario, Loadrunner license arguments).
115. What do you mean by initialization of quota?
Capabilities of the host that at a time how many vuser are initialize.
116.When the load runner controller opens the winrunner file, then what is the location of the winrunner configuration file?
Wrun.ini
117.. What is scenario default?
Instruct the Vuser to use the winrunner configuration file.
118.. What is local configuration file?
Instruct the Vuser to use hosts winrunner configuration file.
119. What do you mean by path?
Use winrunner configuration file i.e., in a specific location on the network.
120.. During run-time where the hosts saves the files?
In temporally in the local drive of each host.
121.. What is script list?
It contain all Vuser script that Vuser can run.
122. What are the information contained by script windows for each script in the list?
1. Name of the Vuser script.
2. Type of the Vuser script.
3. location(Path).
4. command line option.
123. how to modify the script?
Using vuser script information dialog box.
124.. What is the purpose of running the scenario?
To check the response time of client or server system under load.
125. Why we insert the rendezvous point while running the scenario?
If a multiple Vuser to perform a task at exactly the same time.
125. When you initialize the Vuser what happens?
The Vuser status change from DOWN to PENDING to INITIALIZING to READY.
If Vuser files to initialize, the Vuser status changes to ERROR.
126. What is pause command?
It changes the status of the Vuser from RUNNING to PAUSE.
I have taken these Questions from software questions website.