checking for the existence of a current_setting ?

Hello,

(Postgres 8.3)

I'm misusing the current settings at some places to store session
variables.

The next function retrieve such a variable, or initialized it with a
default value.

It is working as expected but performances are slow due to the exception
block.

Is there a way to make the check more smoothly, i.e. without relying on
the exception ?

maybe some undocumented internal function ?

many thanks,

Marc Mamin

CREATE OR REPLACE FUNCTION public.var_get_check(int,text)

RETURNS text AS

$BODY$

BEGIN

return current_setting('public.' || $2 || pg_backend_pid());

EXCEPTION when undefined_object then

perform set_config ('public.' || $2 || pg_backend_pid(), $1::text,
false);

return $1::text;

END ;

$BODY$

LANGUAGE plpgsql VOLATILE

COST 100;