Re: are there static variables in pgsql? - Mailing list pgsql-general

Patrick TJ McPhee wrote:

>I'm not sure a static variable is the right way to achieve this, but
>you could use a custom_variable_class for this. Add this to your
>postgresql.conf:
> custom_variable_classes='global'
>
>Then you can set and show variables prefixed by global.:
> set global.success = 'true';
>
>
>
This is very intriguing, but I'd like to make sure it is doing what I
think it is doing.  Is it tracking variables in a connection across SQL
commands?  If so, shouldn't this work (Assume the existence of table
"detail" with a column called "val2").

create or replace function SetVal2() returns void as
$$
begin
    update detail set val2=global.val2;
end;
$$
language plpgsql

set global.val2=5;
select SetVal2();

I'm getting the following error which I don't understand.  Seems I don't
know how to access the variable once it is set.

ERROR:  missing FROM-clause entry for table "global"
CONTEXT:  SQL statement "update detail set val2=global.val2"
PL/pgSQL function "setval2" line 2 at SQL statement