Friday, February 26, 2010

Loadrunner - Web(HTTP/HTML) Vs WEB,AJAX(Click & Script) protocol in terms of virtual user

Loadrunner - Difference between Web(HTTP/HTML) and WEB,AJAX(Click & Script) protocol in terms of virtual user

Web (HTTP/HTML) protocol script consist of series of requests. Loadrunner start processing the requests one by one, once request is completed after receiving the response, it just forget what happened and proceed with the next request, so it consume less memory and don't process any web page code.

Where as click & script protocol virtual user is a hidden browser, it works similar to the real browser by executing the web page code, so correlation is not required . By using very limited object properties, HP could implement QTP technology into this protocol. User can also access page DOM using java script similar to .Object in QTP. Naturally it consume more memory and create more load on load injectors.

If the application is using heavy AJAX and third party controls, it may consume lot of memory and CPU usage. Always monitor load generator memory and CPU usage, it should not go beyond 80%. Some time Vusers run very slowly after couple of iterations, not meeting the script expectation.
In these situation, we do have following issues when virtual users are running as "thread".
Some of the virtual users may fail with the following error message
Action.c(360): Error: C interpreter run time error: Action.c (360):  Error -- memory violation : Exception ACCESS_VIOLATION received.
Function Specific error
Action.c(360): Notify: CCI trace: Action.c(360): web_browser(0x02081b03 "Java_Script", 0x0208214f "ACTION", 0x02081292 "EvalJavaScript=igtbl_getRowById('ctl00xc...", 0x02082111 "LAST")
In-order to overcome above error, run the virtual user as "process" instead of "thread", now virtual users are stable and each is assigned separate memory.
Loadrunner create virtual user using mmdrv.exe process, if virtual users are running as process, virtual user count and mmdrv.exe process in the task manager count will be same.
Install load injectors with Windows 2003 64bit to accommodate more memory.


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