Minimize your script debug time by using “On demand log functions" in Load Runner

More than often, I see people using Log settings available in Run-Time settings and completely ignore the function “lr_set_debug_messag(),” which I think Mercury has thoughtfully created, because it is genuinely useful in many occasions. Say, you’re dealing with a script with 5,000 lines and you have trouble correlating a certain dynamic string which you know for sure appears after a certain request in the 2000th line is fired to the AUT. Now, if you were to use just use the Extended Log option from the Run-Time settings of LoadRunner, then, it would take huge about of time during replay to arrive till the 2000th line of the script, because it has to parse and display all the data returned from server onto the screen – right from the beginning of the script.

Here is when “lr_set_debug_messag()” comes in handy. All you have to do is place this function above the request which generates the response from where you intend to debug your script. Make sure that you turn off Extended Log option in the Run-Time settings when you use this function. This measure ensures that your extended log option is triggered only at places where you want them and hence will save you huge amount of time while debugging.

In the below example, I have created three functions and I generally place these functions inside global.h section of my script. During debug cycles, I just call “logs_on()” function when I need extended log(with data returned from server and parameter substitution details enabled) for a certain server response and I use “logs_off()” function at the line in the script from where I don’t want anymore logs to be displayed. And I use “logclear()” function when LoadRunner doesn’t respond to logs_off() function(It is a known defect.)

logs_on()
{
lr_set_debug_message(LR_MSG_CLASS_EXTENDED_LOG |LR_MSG_CLASS_RESULT_DATA| LR_MSG_CLASS_PARAMETERS , LR_SWITCH_ON );
}

logs_off()
{
lr_set_debug_message(LR_MSG_CLASS_EXTENDED_LOG |LR_MSG_CLASS_RESULT_DATA| LR_MSG_CLASS_PARAMETERS , LR_SWITCH_OFF );
}

void logclear(void)
{
unsigned int log_options = lr_get_debug_message();
lr_set_debug_message(log_options, LR_SWITCH_OFF);
return;
}