Posted by Makeshkumar A
November 30th, 2012

Below are the advanced options of load runner’s runtime settings. It has below 5 properties.

  • HTTP
  • General
  • Authentication
  • Log
  • Web (Click and Script) Specific, Every property needs to be assign with appropriate values.

These settings are default values given by HP LoadRunner. Generally most of the performance testers will not change the default values until and unless their script needs anything from the settings.

This article lists the frequently used advanced options in Runtime settings.

Navigation:   Run-Time Settings > Internet Protocol >Preferences > Options

General_Run time_Settings

HTTP: HTTP Version:

This option enables you to select which version of HTTP that you want emulate by the Vuser wherever it is hitting the webserver. This information will be available in HTTP Request header. HTTP 1.0 and HTTP1.1 are the two versions available in load runner.

Keep-Alive timeout: The number of seconds the server will wait for subsequent requests before closing the connection with client. If the value is high, it may leads to some  performance problem. The default value for this property is 60 seconds.

HTTP-request connect timeout: The time that Vuser will wait for the connection of a particular HTTP Request before it got failed. It is specified in seconds. The default value for this option is 120 seconds.

HTTP-receive receive timeout: Time taken between sending a full HTTP Request to the webserver and receiving response from the same. In other words, the time it takes between TCP/IP connection setup and the receipt of a complete HTTP request from the Browser. The default value for this option is 120 seconds.

Run Time_Settings_for_HTTP

General:  DNS Caching:

A DNS cache is a database maintained by a computer’s operating system which stores all the details of the recently used internet domains.  When you select YES as DNS Caching all the VUser will hold the information of the host’s IP Address, the same information will be used for subsequent calls to the same server that saves the time.

Step Download Limit: The time taken that Vuser will wait before aborting the particular transaction in the business process. It will be very much used for Vuser activity of not waiting for more than defined value. The Default value for Step Download limit is 60 Seconds.

Network Buffer Size: Sets the maximum number of the network buffer that may be used by the timeout errors if you need less than 1,000 seconds Vuser. This setting is primarily for advanced users who have determined that the network buffer size may affect their script’s performance. The default is 12288 bytes


Mostly we will not change anything for Authentication and log values. It would be good if we keep the default values for those properties.

Web (Click and script) specific

It has the following sub categories

  • General
  • Timers
  • History
  • Navigator Properties
  • Screen Properties
  • Memory management


Home page URL: This field contains the homepage of the browser. By default this field would be blank.

DOM Based Snapshots: Document Object Model (DOM) is an API for HTML and XML Documents. It provides you the structure of the documents and how it is going to accessed and manipulated. When we select yes for this option, VuGen will generate snapshots from the DOM instead of from the server responses.


Fail on JavaScript error: This option will make the Vuser fail when java script error occurs. By default the value for this is NO.

History: History Support: This option tells every Vuser to store the window. History Object in the first iteration. The same details will be used in subsequent iteration by the Vuser. Enable, disable and auto are the available values for this property. For better performance we need to disable this option.

Window. History The history object contains the URLs visited by the user within a browser window.

Maximum history Size: The maximum no of steps that can be stored in the window.hsitory object. Default value: 100Steps

Memory Management: This option allows you to change the memory options for dynamically created DOMs, java script runtime memory size and stack memory size in the recorded script. It would be mainly helpful if you are working with large video file upload/download business scenarios.  Before going into the LR Memory options we need to get some idea on DOM and Stack memory size.

Web (Click and Script)

When a machine doesn’t manage its memory allocations correctly, then it is a memory leak. A memory leak may affect the system performance. Internet Explorer contains a number of leaks, the worst of which is an interaction with JavaScript. When a DOM object contains a reference to a JavaScript object (such an event handling function), and when that JavaScript object contains a reference to that DOM object, then a cyclic structure is formed. As a result, when cycles occur, memory reclamation does not occur. The memory that is not reclaimed is said to have leaked. Over time, this can result in memory starvation. In a memory space full of used cells, the browser starves to death.

For more details on the java script memory leaks please click this article:

Now, we will look on the memory options which is available in load runner runtime settings

Defaults block size for DOM memory allocations: it will allocate the memory size for DOM Memory objects created at run time. The size of the value depends upon the business scenario which you are running. If you are running scripts which create more DOM objects then the value needs to be high. Default value is 16KB.

Memory Manager for dynamically-created DOM objects: This instructs Vuser that whether they uses the Memory manager for dynamically created DOM objects. If you are using SAP protocol then it is not recommended to use the Memory manager otherwise it should be in AUTO mode.


JavaScript Run time memory size (KB)

If your script has any java objects, then at the time of execution extra memory will be needed for the JavaScript that is being executed in current iteration. Load runner provides the option which will allocates the memory for currently running java scripts. The default value for this option is 1KB. If your scenario is going to produce more number of java objects (scripts) which will be occupying more memory then you should be increase the value for this.

JavaScript Stack memory size (KB)

In case your scenario exceeds the default stack size, you might be getting stack overflow Error. To overcome this issue you have to increase the java script stack memory size manually. The default value for this option is 32 kb.

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