JMeter script is not working in desired way for all users

Question

I am running a recorded Test Plan in which, I have assigned 5 different users to the Thread Group, with a Ramp-up period of 5 and Loop Count of 1.

This is what happens after executing the script:

The test runs without errors and when I verify the results in 'View Results Tree' listener, I find all users got successfully executed without any error, but when I verify the same in system; only 2 or 3 users got registered. I deleted the registered users and ran the script again, and this time too only 2 or 3 users got registered (this time different 3 users out of 5 got registered) i.e. user selection for registration is random, but count remains only 2 or 3 out of 5 users.

I don't understand

1. What can be the possible reason for this behavior of my test?
2. Why my Test Plan is not registering all the 5 users?

I've checked the resource utilization on my machine too, but they were fine, no problems with that.

Answer 1

This may have to do with the way your application is built. Apparently, your application doesn't throw an error (validation error) when the duplicate credentials are used to register. Ideally, there should be an error (4xx) in such cases. Just because your script got executed and there is all green in the View Results in Tree listener doesn't mean Users got registered. Do check the request and response in the View Results in Tree listener.

Alternatively, you can try hitting the same endpoint (URL) using a Rest Client tool like POSTMAN. If the endpoint gives 200 or 201 on use of duplicate credentials for registration, then ask the developer to fix it!

Thanks!

Answer 2

It really depends on what queries you are executing to create those users. If the queries are creating the same user all 5 times, using 5 threads, then the threads could over-run each other. I think as long as you are careful to track which thread is doing what, you shouldn't have a problem.