[phamilton]

Since Ruby's GIL means you can't do true parallel processing, it's common to kick off multiple worker processes and have them each take one job at a time.

If the job involves an expensive API call it will tie up a worker for the duration of the call.

So it's not so much ~thousands of jobs per second as it is a limitation of only 10 ruby processes per 1GB of memory. (A ruby process with the Rails env loaded is about 100MB.)

Elixir gives you the ability to make a few orders of magnitude more calls in a tiny amount of memory. (100,000 Elixir "workers" can be had in less than 1GB).