Global variables for multiple instances

One of the features that Postman doesn’t have and we really need is the ability to run tests in parallel. We have thousands of tests organized in collections that would take too long to run sequentially. So we launch multiple newman instances (which I think each one runs Postman or the Postman core) in parallel. Rule of thumb is as many newman instances as there are cores. This way we can cut down on the overall processing time for all of our regression tests.

We make heavy usage of global variables, but I’m afraid that when running 2 newman collections at the same time that use the same global variable (name), they will overwrite each other’s data. For example, let’s say that newman instance 1 is running collection A which just set the “foobar” global variable to “XXX”. At the same time, newman instance 2 is running collection B which is setting the “foobar” global variable to “YYY”. Will instance 1 see “XXX” or “YYY”? IOW, are the global variables global per newman/Postman instance or across instances?