VuGen: Using Undocumented Functions

From James Pulley:

I have never really cared for the use of the lr_user_data_point() and
having to pull up the user defined graphs for analysis. Instead I take
advantage of some undocumented functions


I use these functions in tandem to determine if I need to create a custom tracking transaction where a transaction has run too long and is out of spec.

I can then compare raw numbers at the end of the test, a ratio of <transaction name>_out_of_spec to <transaction name> to for a quick sanity check on the quality of the application. As quality and scalability improve, the ratio of _out_of_spec to base should become smaller and smaller – approaching zero. Even Six Sigma quality control allows one sample deviation out of a million, this _out_of_spec tracking can be incorporated as part of statistical measurement of performance quality.

Time now to pull out SAS or SPSS to figure out if you’re 1,2,3,4,5, or 6 sigma on your number of defects :). Prototypes for lr_set_transaction() and lr_get_transaction_duration, as well as many other interesting functions, can be found in the LRUN.H file, in the ..\LoadRunner\include directory.


Know of any other good undocumented functions? Send them to me at

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Scott Moore

About Scott Moore (153 articles)

With over 20 years of IT experience with various platforms and technologies, Scott has tested some of the largest applications and infrastructures in the world. He is a Certified Instructor and Certified Product Consultant in HP’s LoadRunner and Performance Center products. He currently holds HP certifications for ASE, ASC, and CI. A thought leader in the APM space, he speaks regularly at IT conferences and events