Re: implemention of calls to stored procs.

Nic Ferrier <nferrier@tapsellferrier.co.uk> writes:
> From what I udnerstand of the architecture it seems that the SPI API 
> is inherently single threaded.

The entire backend is inherently single-threaded.

> If not, am I right? Can only one user supplied proc be running at once 
> across the whole postgres engine? 

What do you consider "the whole engine"?  Each connection has its own
backend process.  Also, SPI is recursive even though not thread-safe:
it's possible for an SPI-executed query to call a function that
performs another SPI query.

			regards, tom lane