Another way to put my question is: is there a hard limit to how many API calls I can make in a minute to Jira Server?
My use case involves daily updates of issues using external data sources- to update issues, I am using api/2/issue and I can never seem to get above ~500 messages/minute (~8 messages/second). I am using 48 parallel processes to bombard jira with API calls but there is definitely some bottleneck that is throttling my requests and I am trying to find those bottlenecks and adjust them to open up a bit more. I am running Jira on a RHEL 7 server with 24GB and 8 CPUs- using top, I can see the server is not the bottleneck as hardly any CPU resources are being consumed and free memory hovers at about ~3GB.
On the database, I have increased min and max DB connection pool settings to 40. Reviewing the database monitoring page, below is a typical graph for my instance:

As you can see, there is a spike when my parallel processes start but then it quickly goes down and hardly consumes any connections.
I would appreciate any guidance on what bottlenecks might exist and where to modify settings to alleviate those bottlenecks. Or any general guidance!
Thanks,
Akshar