[SQL] checking for the existence of a current_setting ?

[Marc Mamin]

 

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;