LoadRunner and the need for pacing

Question

Running a single script with only two users as a single scenario without any pacing, just think time set to 3 seconds and random (50%-150%) I experience that the web app server runs of of memory after 10 minutes every time (I have run the test several times, and it happens at the same time every time). First I thouhgt this was a memory leak in the application, but after some thought I figured it might have to do with the scenario design. The entire script having just one action including log in and log out within the only action block takes about 50 seconds to run and I have the default as soon as the previous iteration ends set not the with delay after the previous iteration ends or fixed/random intervalls set.

Could not using fixed/random intervalls cause this "memory leak" to happen? I guess non of the settings mentioned would actually start a new iteration before the one before ends, this obvioulsy leading to accumulation of memory on the server resulting in this "memory leak". But with no pacing set is there a risk for this to happen?

And having no iterations in my script, could I still be using pacing?

Please update post with some code snippets.. it's always easier when you see what's going on .. — K.Sandell, Apr 11 '13 at 23:00

score 0 · Answer 1 · answered Apr 11 '13 at 23:00

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To answer your last question: NO.

Pacing is explicitly used when a new iteration starts. The iteration start is delayed according to pacing settings.

Speculation/Conclusions:

If the web-server really runs out of memory after 10 minutes, and you only have 2 vu's, you have a problem on the web-server side. One could manually achieve this 2vu load and crash the web-server. The pacing in the scripts, or manual user speeds are irrelevant. If the web-server can be crashed from remote, it has bugs that need fixing.

Suggestion:

Try running the scenario with 4 users. Do you get OUT OF MEMORY on the web-server after 5 mins?

answered Apr 11 '13 at 23:00

K.Sandell

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I was able to add pacing to my scenario on the controller with just one action in my script? – Magnus Jensen Apr 12 '13 at 13:43
The pacing only affects the delay between Iterations, regardless of the number of actions in the script – K.Sandell Apr 13 '13 at 12:26

score 0 · Answer 2 · answered Apr 03 '14 at 19:40

If there really is a leak, your script/scenario shouldn't be causing it, but I would think that you could potentially cause it to appear to be a problem sooner depending on how you run it.

For example, let's say with 5 users and reasonable pacing and think times, the server doesn't die for 16 hours. But with 50 users it dies in 2 hours. You haven't caused the problem, just exposed it sooner.

score 0 · Answer 3 · answered Apr 09 '14 at 08:59

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i hope its web server problem.pacing is nothing but a time gap in between iterations,it's not effect actions or transactions in your script

answered Apr 09 '14 at 08:59

sivaramaraju

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LoadRunner and the need for pacing

3 Answers3