If you need user-accessible shared variables, you could take a look at
how Veil http://pgfoundry.org/projects/veil/ achieves this.
Veil provides a limited number of shared variables with an API for SQL
access. The variables may only be set during initialisation or reset to
avoid system state changing part-way through a transaction. Veil goes
to considerable trouble to deal with this. If this is not a concern for
you, you may be able to do something simpler but you would have to
perform extra locking on assignment.
Feel free to take whatever you can from Veil.
__
Marc
> Date: Sun, 16 Oct 2005 18:54:21 -0500 (CDT)
> From: <cristian@clickdiario.com>
> To: doug@mcnaught.org, tjo@acm.org
> Cc: "pgsql-general@postgresql.org" <pgsql-general@postgresql.org>
> Subject: Re: dynamic loading of .so
> Message-ID: <ozXzqVpq.1129506861.7416760.cristian@clickdiario.com>
>
>
> are there any way to make them global for all the instances?
>
> On 10/14/2005, "Douglas McNaught" <doug@mcnaught.org> wrote:
>
> >TJ O'Donnell <tjo@acm.org> writes:
> >
> >> I have begun to use some static variables in my c-language
> >> functions to maintain state (3rd party licensing issues) during
> >> the course of a session (postgres process, spawned by postmaster).
> >> These are declared static outside the scope of any function.
> >> (is global the correct term anymore?)
> >> When I use dynamic loading of my .so,
> >> each session is independent, with its own static variables.
> >> Will the same be true if I were to load the .so once when
> >> the database starts up? Or will there be just one set of
> >> static variables for all sessions?
> >
> >Each backend process has its own memory space, so the variables will
> >still be independent.
> >
> >-Doug