Wishing all Learn LoadRunner readers a very happy new year – 2010!

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Points to note with web_url and web_link:

• web_url is not a context sensitive function while web_link is a context sensitive function. Context sensitive functions describe your actions in terms of GUI objects (such as windows, lists, and buttons). Check HTML vs URL recording mode.
• If web_url statement occurs before a context sensitive statement like web_link, it should hit the server, otherwise your script will get error’ed out.
• While recording, if you switch between the actions, the first statement recorded in a given action will never be a context sensitive statement.
• The first argument of a web_link, web_url, web_image or in general web_* does not affect the script replay. For example: if your web_link statements were recorded as

  web_link("Hi There",
           "Text=Hello, ABC",
           LAST);
  

  Now, when you parameterize/correlate the first argument to

  web_link("{Welcome to LearnLoadRunner}",
           "Text=Hello, ABC",
           LAST);
  

  On executing the above script you won’t find the actual text of the parameter {Welcome to Learn LoadRunner} instead you will find {Welcome to Learn LoadRunner} itself in the execution log. However to show the correlated/parameterized data you can use lr_eval_string to evaluate the parameter.

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We will see step-by-step procedure of how to handle the pop-up windows while using Oracle NCA protocol:

1. Put the title of the pop-up window in nca_obj_status function.
2. Find out where the pop-up is occurring, put the handling statement below it.
3. The handling statement could be nca_popup_message_press or nca_message_box_press. To find out which function is suitable for your script, record a script using data that generates that popup window, click on the button and check which function gets recorded.

Example:

This piece of code will trigger a pop-up:

nca_set_window( "PopUpObjects");
nca_lov_retrieve_items("PopUpObjects",1,20);
nca_lov_select_item("PopUpObjects","POP UP NOTIFICATIONS");

If title of the window is “Warning”, put it inside the nca_obj_status function. The code would be something like-

int status;
status=nca_obj_status("Warning");
if (status = = 0)
nca_popup_message_press("Warning","OK");
// nca_message_box_press("Forms",1); Any one of them

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• When a script is opened in Controller, run-time settings  also gets copied from VUGen to controller. Check out components of LoadRunner.
• Any changes done in the script and run-time settings are not reflected in the controller unless you refresh them.
• Refresh in controller can be done by going to Design > {Highlighting scenario group} that are using script in question > Clicking Details button > Clicking the REFRESH button on the Group Information pop-up window. So next time when controller asks you to load new script iteration settings do the refresh.
• While doing Save As:
  • Default directory in VUGen can be changed by going to vugen.ini file located under C:\Program Files\HP\LoadRunner\config and appending the required file path to LastScriptPath (as shown on the right).
  • Default directory in Controller can be changed by going to wlrun.ini file located under C:\Program Files\HP\LoadRunner\config and appending the required file path to M_ROOT
• Note that THINK time is ignored in VUGen while played back as recorded in Controller.

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HP has released LoadRunner 9.5 and it is now available for download [2.29GB iso file]. Below is the summary of new features introduced in it:

• LoadRunner noobs always struggle finding out the protocol behind a given application. It seems HP has noted the fact and have come out with a cool new feature called Protocol  Advisor. It sits inside VUGen. Protocol Advisor helps you to determine an appropriate protocol for recording a Vuser script. The Protocol Advisor scans your application for elements of different protocols and displays a list of the detected protocols. These protocols can provide a starting point for finding the optimal protocol for your application.

• Now you have the facility to export the Test Result from VUGen scripts to HTML and open Quality Center defects directly from the report.

• HP Service Test is now fully integrated with LoadRunner. You simply need to buy a license for service test to use its capabilities. [for the uninitiated, HP Service Test automates the testing process for services (SOA). Read more about it in this document.

• LoadRunner 9.5 supports Windows Vista SP1. (LoadRunner 9.1 only supported generators while LR9.5 provides support for both generator as well as controller). To use LR9.5 on Vista, make sure that User Account Control (UAC) is enabled for users with User privileges.

• LoadRunner 9.5 provides support upto .NET Framework 3.5 version and supports .NET and Web Services protocols.

• LoadRunner is now integrated with a 3rd party software Shunra, to provide you access to WAN emulation. Read the complete list of features here.

• Now you can define a Post Collate Command inside the Controller that it will run directly after it collates the results of a scenario run.

• LR controller has a new utility called Host Security Manager utility that will allow you to create secure communication channels between the LoadRunner Controller and load generators.

• There is a new Analysis API that will allow you to create an analysis session from test results, analyze raw results of an Analysis session, and extract key session measurements for external use.

• LR analysis now supports SQL Server 2005.

• LoadRunner 9.5 no longer supports Windows 2000.

• LR 9.5 is compatible with Quality Center(QC) 9.2, 10.0 and QTP 9.5 and 10.0 versions.

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We have talked in length about RAM, memory leakage and how to calculate memory requirements. The question is, what shall we do if we run out of RAM/memory?

The word increasing RAM is actually a misnomer. We all know RAM comes in the form of a chip and that is fixed, when we say increasing memory/RAM we mean to increase the Virtual memory associated with RAM. We have already seen that when a system runs out of space it allots some of the RAM to virtual memory . So can you increase this virtual memory?

1. Go to Start > Control Panel > System > Click on ‘Settings’ under Performance section.
2. Now go to advanced tab. Click ‘Change’ under Virtual Memory section.
3. Select the drive where your paging files reside. Generally they are present in C: drive. Change the value and click on ‘Set’.

The steps given above are for Windows XP professional. I believe steps for other OS will more or less be the same.

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Memory requirement also called as Memory footprint for a Vuser can be called as a function that is dependant on Vuser type (Web, CITRIX, SAP GUI); application and system where you intend to run the test.

So if your Web/HTTP Vuser takes 5MB when running as a process, 50 Vusers would take 250 MB. Then remote desktop connection , third party program (that is continuously running in background) , memory consumed by application all summed will give you the memory requirement for a test.

You can calculate it empirically. Do it for say 10 Vusers and than extrapolate that requirement for x no of Vusers.

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Continuing with our discussion on technical terms used in loadrunner, we will now see the meaning of memory leak and page fault and how they affect loadrunner performance .

What is memory leak?

A memory leak is a particular type of unintentional memory consumption by a computer program where the program fails to release memory when no longer needed. This condition is normally the result of a bug in a program that prevents it from freeing up memory that it no longer needs.This term has the potential to be confusing, since memory is not physically lost from the computer. Rather, memory is allocated to a program, and that program subsequently loses the ability to access it due to program logic flaws.

What is a page fault?

An interrupt that occurs when a program requests data that is not currently in real memory. The interrupt triggers the operating system to fetch the data from a virtual memory and load it into RAM.

An invalid page fault or page fault error occurs when the operating system cannot find the data in virtual memory. This usually happens when the virtual memory area, or the table that maps virtual addresses to real addresses, becomes corrupt.

Now the most important question comes up, how do they affect LoadRunner functioning?

As you might guess, memory leak, if left unattended and not corrected, could prove to be fatal. Memory leaks can be found out by running tests for long duration (say about an hour) and continuously checking memory usage.

Issues caused by memory leaks are essentially based on two variable for a standalone windows application 1) Frequency of usage 2) size of memory leak . If either one or both are very high it could cause the computer to come to a point when no memory is available for other applications causing it to crash. If it is a network based application then you will also have to consider network traffic . If each network transaction causes a memory leak , then a high volume of network transactions could also prove dangerous.

References:
Wiki
Webopedia

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There are three types of recording mode/levels in LoadRunner. GUI-based, HTML based and URL based. For the uninitiated, recording levels tells you the amount of and what information is recorded during the recording process. As the title says, for this post we will keep focus on HTML based and URL based recording levels only and will touch upon GUI based mode, in a later post.

1. HTML based mode, records script for every user action that is performed during recording (hmmm…sounds like QTP) while URL based mode records each and every browser request to the server and resources received from the server. Confused? ok, HTML based mode does recording as you perform clicks and doesn’t give you inside information like what is happening behind the recording while URL based mode records each and every step and emulate Javascript code.
2. From the point1) above you can guess, HTML mode would have less correlation to do while URL mode has much more complex correlation requirements.
3. HTML mode is smaller and is more intuitive to read as the statements are inside the functions corresponding to the user action performed. In the case of URL based, all statements gets recorded into web_url()
4. HTML mode is recommended for browser applications while URL mode is recommended for non-browser applications.
5. Lastly, don’t get the impression that I am advocating for HTML mode . URL mode can be of real help when you want to have control over the resources that need to be or need not to be downloaded, since you have each and every statement in-front of you (point 1)

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Related posts:

1. All about web_url and web_link in LoadRunner

Process is defined as the virtual address space and the control information necessary for the execution of a program while Threads are a way for a program to split itself into two or more simultaneously running tasks. In general, a thread is contained inside a process and different threads in the same process share some resources while different processes do not.

Source

In terms of Loadrunner, when we run Vuser as a process, LoadRunner creates 1 process called mmdrv.exe per Vuser. So if we have 10 Vusers, we will have 10 mmdrv.exe processes on our machines.

while when we run Vuser as a thread, LoadRunner creates 1 thread per Vuser. So if we have 10 Vusers, then we will have 1 process with 10 threads running inside it if the limit is 10 threads per process.

Running Vuser as a thread is more memory efficient that running Vuser as a process for obvious reasons that less memory resources are utilized when we run them as thread. I read somewhere that running as a process has an advantage that system becomes more stable. Now how is that         stability achieved? I am not sure…Can someone clarify this point to me?

Note that while running Java Virtual User, JVM’s are loaded per process and will follow the same principle above.

Related: What is RAM, Memory Usage, CPU Usage, Paging in terms of LoadRunner?

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