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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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