Re: can I define own variables?

Tom Lane wrote:
> Guy Rouillier <guyr-ml1@burntmail.com> writes:
>> Tom Lane wrote:
>>> Another possibility, if you only need to store and retrieve values
>>> and not do anything especially interesting with them, is to abuse
>>> the "custom GUC variable" facility.
>
>> I've had several occasions when a user-defined variable would have come
>> in handy.  What is the scope of user_vars as you've defined them above?
>
> They'd act like any other GUC variable.  The scope of a SET would be the
> current connection, but there are other ways to set them with larger scope.

8.2.0 on Windows doesn't like "user_vars" as a value for
custom_variable_classes, but "uservars" is okay.

I set that up, and using the SHOW command returns the set value.  I
searched the archives and I couldn't identify a way to retrieve these
values in a trigger function.  When I try to execute the following:

CREATE OR REPLACE FUNCTION assign_user_name() RETURNS trigger AS $$
     BEGIN
         NEW.user_name := (SHOW uservars.user_name);
         RETURN NEW;
     END;
$$ LANGUAGE plpgsql;

it complains:

ERROR:  syntax error at or near "uservars"
LINE 1: SELECT  (SHOW uservars.user_name)
                       ^
QUERY:  SELECT  (SHOW uservars.user_name)
CONTEXT:  SQL statement in PL/PgSQL function "assign_user_name" near line 2

********** Error **********

ERROR: syntax error at or near "uservars"
SQL state: 42601
Context: SQL statement in PL/PgSQL function "assign_user_name" near line 2

I tried the same with a standard GUC (deadlock_timeout) and got the same
error, so this has nothing to do with custom classes.  How can I
retrieve GUCs within a pl/pgsql function?  Thanks.

--
Guy Rouillier