Load Runner - Qs

1. What is load testing?

Load testing is to test that if the application works well with the loads from large number of simultaneous users and transactions. It also used to determine whether it can handle peak usage periods.

2. What is load runner?

Load Runner is a performance testing tool from HP. This tool supports all aspects such as Load, Stress, Endurance, data volume and spike Testing.

3. What are all the components of LoadRunner?

Following are the components of LoadRunner

• The Virtual User Generator
• Controller, and the Agent process
• LoadRunner Analysis and Monitoring
• LoadRunner Books Online

4. What Component of LoadRunner is used to record a script?

The Virtual User Generator (VuGen) component is used to record a script and it enables you to develop Vuser scripts for a variety of application types and communication protocols.

5. What is a rendezvous point?

Rendezvous points are introduced into Vuser scripts to simulate more users on the server. Rendezvous points instruct Vusers to wait during test execution in order to perform the tasks simultaneously.

For example, in a banking application, Rendezvous points are inserted for 100+ multiple users to deposit money simultaneously.

6. What is a scenario?

A scenario is nothing but an event that occurs for each testing session.

For example, a scenario defines

• Number of users
• Action to be performed
• Virtual machines system

7. How can we debug a LoadRunner script?

VuGen contains two options to debug Vuser scripts

• Run Step by Step command and
• Breakpoints.

We can also manually set the message class within your script using the lr_set_debug_message function.

8. How can we perform functional testing under load?

Functionality under load can be tested by running several Vusers concurrently. By increasing the Vusers, it is necessary to determine how much load the server can sustain.

9. What is the relationship between Response Time and Throughput?

The Throughput shows the amount of data in bytes that the Vusers received from the server in a second. When It is compared with transaction response time, throughput and response time get decreased.

The peak throughput and highest response time would occur approximately at the same time.

10. What does vuser_init and vuser_end action contain?

Vuser_init action contains procedures to login to a server and Vuser_end section contains log off procedures.

11. What is the difference between standard log and extended log?

The standard log sends a subset of functions and messages to the output log and subset of functions depends on the Vuser type.

Extended log sends a detailed script execution messages to the output log. It is mainly used during debugging when user needs information about Parameter substitution.

12. What are all the types of Goals in Goal-Oriented Scenario of Load Runner?

Load Runner provides you with five different types of goals:

• Number of concurrent Vusers
• Number of hits per second
• Number of transactions per second
• Number of pages per minute
• Transaction response time

13. What is a function to capture dynamic values in the web vuser script?

Web_reg_save_param is the function that saves dynamic data information to a parameter.

14. What are the Load Runner testing process?

Following are the testing process in LoadRunner:

• Plan load test
• Create Vuser Scripts
• Define Scenario
• Run Scenario
• Analyze results

15. What is remote command launcher?

The remote command launcher enables the controller to start applications in the host machine.

16. How can we develop the database vuser script?

Vuser scripts can be developed either by recording with the load vuser script generator or by using Load runner vuser script template.

17. How do you load a load runner Agent?

While running the scenario, loadrunner controller instructs the remote agent dispatcher to launch loadrunner agent. The controller instructs the loadrunner agent to initialize, run, pause and stop the vusers.

18. What is the difference between hits/second and requests/second?

Hits per second means the number of hits the server receives in one second from the vuser.

Request per second is the number of request the vuser will request from the server.

19. What are the advantages of load runner?

Following are the advantages of Load Runner:

• Reduces human intervention
• Reduces the requirement of the systems
• Helps in the better usage of time and money
• Effective utilization of automation
• Single point execution

20. What is the vuser in the scenario?

The vuser is the virtual users who can simulate the real users. The virtual users who take the place of real users’s operating client software, such as IE sending requests using the HTTP protocol to IIS or Apache web servers.

21. How do we write a user defined function in LoadRunner?

Use should create the external library that contains the function. This library must then be added to the bin directory of VuGen. And then, the user-defined function can be assigned as a parameter.

22. What are the changes that can be made to run-time settings?

There are four run-time settings that can be made:

• Pacing: This contains iteration count.
• Log: Logging can be set to standard or disabled.
• Think Time:  Capable of setting think time to be ignored or replayed.
• General:  Allows the setting of Vusers for processes or multithreading.

23. How can we find database related issues?

Monitors and the Data Resource Graph can be used to find database related issues. LoadRunner allow the tester to specify the resource that needs to be measured before the controller is run.

24. How many types of graphs are available in LoadRunner?

There are 5 types of graphs:

• Network delay time graph – displays the time that elapses between request and response
• Two transaction response time graphs – one transation response time graph for load and another one for percentile
• Hits/second graph – Shows application traffic volume
• Pages download/second graph – shows the rate at which pages are downloaded per second

25. How can performance bottlenecks can be identified?

Monitors can be used to detect performance bottlenecks. These include network, web server, application server, and database server monitors.

These monitors can be used to locate trouble spots in scenarios that cause increase in response time and throughput, network delays, performance response time, hits/second, etc.

26. What is ramp up and how it can be set?

Ramp up is gradually increasing the load on a server and can be simulated by gradually increasing the number of Vusers.  This feature can be found in the Scenario Scheduling Options.

27. How correlation can be performed?

Correlation can be performed in two ways:

    Use the scan function to search for correlations and select a value from the result.

    Record a pair of scripts and then compare them to each other.

28. Where are automatic correlation options set?

The automatic correlation is set in recording options area on the correlation tab. Correlation can be enabled for the full script and rules for correlation can be defined.

Automatic correlation can be performed on a database by viewing the output window, scanning for correlation, and selecting the value that will be used.

29. What is the benefit of running a Vuser script as a thread?

The advantage of running a Vuser script as a thread which allows more Vusers to be used for one load generator. Running Vuser scripts as processes utilizes a lot of memory because all of the loaded scripts use the same driver.

This limits the number of Vuser scripts that can be run on one generator.

30. What is the difference between Overlay graph and Correlate graph?

Overlay Graph:

Overlay graph has one X axis and 2 Y-axis. Left Y-axis on the merged graph shows the current graph’s value & Right Y-axis show the value of Y-axis of the graph that was merged.

Correlate Graph:

There are two graphs and  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.

31. What are the three sections of a Vuser script and what is the purpose of each one?

Following are the three sections of Vuser script and they are as follows:

    Vuser_init – Used for recording the logon.

    Actions – Used for recording the business process.

    Vuser_end – Used for recording the logoff.

32. What are the four selection methods when choosing data from a data file?

Following are the four selection methods:

    Sequential

    Random

    Unique

    Parameter name

33. What should be done to view parameter substitution in the Execution Log?

Parameter substitution can be viewed in the extended log in the Run time settings.

34. What tools are required to analyze Vuser run results?

Following tools are required to analyze Vuser run results:

    Execution Log

    Run-Time Viewer and

    Mercury Test Results window

35. What is difference between Manual scenario and Goal oriented scenario?

Following are the differences between Manual and Goal Oriented scenario:

Manual Scenario	Goal Scenario
Main purpose is to learn how many Vusers can run concurrently	Goal may be throughput, response time, or number of concurrent Vusers
Gives you manual control over how many Vusers run and at what time	Load Runner manages Vusers automatically

36. What are all the reasons to use the Server Resources Monitor?

Server resources monitor is used to find how much data is coming from Cache and helps to find out what are all the parts of the system have bottlenecks.

37. What is the purpose of selecting ‘Show browser’ during replay in the General Options settings?

‘Show Browser’ setting is used to see the pages that appear during playback. This is useful for debugging Vuser during the initial stages of Web Vuser creation.

38. For what purpose, User will be using ‘continue on’ error?

Continue on should be set only when making Execution Logs more descriptive or adding logic to the Vuser.

39. What is the purpose of a LoadRunner transaction?

The purpose of a Load Runner transaction is to measure one or more steps/user actions of a business process.

40. Why do you create parameters?

Parameters are like script variables and they are used to vary input to the server to emulate real users.

    Different sets of data are sent to the server whenever the script is run.

    Better simulate the usage model for more accurate testing from the Controller and one script can emulate many different users on the system.

41. What is lr_output_message?

The lr_output_message is a function that sends notifications to the Controller Output window and to the Vuser log file.

42. In a Web server, Database and Network are all working fine and now, 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.

43. What is VuGen Recording and Scripting?

LoadRunner script code is obtained by recording in the ANSI C language syntax and it can be viewed in the script view.

44. What is Performance testing in LoadRunner?

Performance testing can be done by calculating the timing for both read and update transactions and check whether system functions are being performed in an acceptable timeframe. In a multi user environment, it is necessary to determine the effect of multiple transactions on the timing of a single transaction.

45. What is the Configuration of systems when using Load Runner?

The configuration of systems refers to that of the client machines in which we will run Vusers. The configuration of 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 so as to achieve the load testing objectives.

46. What is the use lr_abort function?

The lr_abort function is used to abort 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.

47. What is think time?

Think time is the time where a real user waits between actions.

When a user receives data from a server or other applications, the user may wait several seconds to review the data before responding. This time delay is called as think time.

48. How Load Runner interacts with the application?

Protocol is used in Load Runner to interact with the application.

49. What is the latest version and language used in Load Runner?

As of 20-Feb-2013 Load Runner 11.5 is the latest version and VUser script is used like a C Language.

Following languages are supported by LoadRunner:

1. C Language

2. Visual Basic Scripting

3. Visual Basic For Applications

4.  Java Scripting

50. What are all the important protocols that Load Runner supports?

Following are the protocols that Load Runner can support are:

.NET Record / Display     Database     DCOM     Network

Oracle E-Business     SAP          SOA     Web and Multimedia     Wireless

GUI     Java Record and replay     Remote desktop     Web 2.0

 

Source#1)  http://career.guru99.com   #2) http://www.softwaretestingstuff.com

Note: Some of the articles are grab from various Websites / Blogs.