Re: SPI shared memory ?

Alex Vinogradovs <AVinogradovs(at)Clearpathnet(dot)com> writes:
> Yes, I'd like to get some memory of my own, so that it can
> be shared between functions executing in different connections.
> Is there an existent API, or should I just straight use Unix IPC ?

As of (I think) 8.2, there's RequestAddinShmemSpace and RequestAddinLWLocks.
However, the fly in the ointment is that you can only usefully call
these from a loadable module that is preloaded at postmaster start;
otherwise it is too late to affect the sizing of shared memory.

There's enough slop in the shared memory allocation that you can
probably grab a few dozen or hundred bytes without a pre-allocation.
One possibility is to do that and use it to store a reference to a
separate shared memory segment.

regards, tom lane