implemention of calls to stored procs.

I've been looking at the implementation of the procedural language
support code with a view to writing a java plugin (ie: something to
allow java classes to be used as stored procs).

From what I udnerstand of the architecture it seems that the SPI API
is inherently single threaded. I think this because of the way that
the SPI stuff work, one calls SPI_connect and then you can do an
SPI_exec to do a query, this sets a global value...


Perhaps I've misunderstood the implementation details and there is
some hidden black magic that means that more than one thread can be
doing some SPI operations?

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



Nic Ferrier