JMeter Open Model Thread Group: use user defined variables

Question

I was trying to use a Open Model Thread Group in JMeter as it seems to be the better way for me to create an equally distributed call of my requests and at the same time limiting/setting the average number of requests per minute. I was not able to get the same results with constant throughput timers here.

There is one thing though which I don't get. The Open Model Thread Group has an input field which allows some custom defined functions to be called: pause, rate, ... But I was not able to get user defined variables inside. I tried using the variables just like in other places ${my_var}, and I tried the entire thing inide a ${__groovy()} block with vars.get('my_var'). But both didn't work. In fact I got exception in the log about null values.

Is there any other way?

Answer 1

I cannot reproduce your issue using latest stable JMeter 5.6.3, variables are getting normally resolved, there are no errors in jmeter.log file:

So I would recommend:

• Upgrading to latest JMeter and LTS JDK (it's recommended to use latest stable versions of JMeter and Java in any case)
• If the issue can be reproduced please update your question with the steps
• It also worth reporting it via JMeter Issues