Queued(?) Calls to RFC wrapped with a Web Service
If a rfc in CRM 5.0 is web service enabled, how are multiple simultaneous calls to the same function from a web service handled? When doing it this way each call is using the same rfc user, correct?
Are the requests queued up? How does SAP runtime resolve two or more calls to the same function form knocking each other out?
Web Service calls inside the ABAP environment are worked on in parallel. So if you have multiple requests coming in the stuff is by no means queued. All of this of course depends on how many worker processes are configured in your system. You can see the worker processes in transaction SM50.
If I recall correctly the first worker thread which starts up acts as a dispatcher for all the other ones ( wow that's a long time ago I might be wrong on that one).
If you do not have enough work processes configured in your system then of course the dispatcher process waits until the next worker process becomes available. This is the limitation to this. If you experience such a problem you have to increase the number of work processes in your system in transaction RZ10. Changing stuff in RZ10 should be done by a system administration. if the machine you are running on is from a hardware perspective not equipped to handle more work processes then you need to have another application server in that system.
Hope that helps.