We’ve had this question posed a couple of times in the past, so we thought a blog article might help to clarify how a load test is being executed.
Load Impact’s basic functionality is geared towards simulating user behavior on your site in the most realistic way possible. In a real live situation, if you were to have 500 users on your website at the same time, you probably won’t have all 500 of them on the same page. Some users might also take time to read material on the page, so not all your users will be loading resources. Load Impact tries to simulate that as realistically as possible. An easy way to do this would be to use one of our features called the Proxy Recorder, which helps you in creating a script simulating a user visiting several pages on your site.
When you start a recording, a new browser window with your target URL opens, and whatever actions you do there will be recorded. The HTTP requests will then be translated to a script when the recording is over, which you can further edit if necessary.
So when you start a test, what actually happens is that we will start by running your script with one user, and slowly ramp up to i.e. 500 VUs. When the script runs to completion, it will re-run itself until the time runs out. Now if you look at your script, you will see that there is something called “client.sleep”. That is the time that the user spends browsing each page, and serves as a simulation of what real users do. At the same time, since we add clients to your site in a ramp up situation, what you will get is that some users would be on Page 3 of your script while others are just starting on Page 1. This will mean that each page will never be subject to a load of 500 concurrent users loading resources at the same time.
However, it is important for you to know what your testing goals and objectives are prior to the scripting of the test. If your test objectives are to simulate a marketing campaign where you expect most of your traffic to flood to one page, the initial example might not be suitable for you. Instead, you might want to dedicate one user scenario which simulates the repetitive loading of one or two pages.
You could then have a few other scripts simulating browsing around the site, and how the minority user behavior would be.
You can create and modify scripts using our text editor or graphical editor, but generally if you’re intending to modify the script dynamically we highly encourage using the text editor, and if it’s simple editing both the text and graphical editor would work.
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