Re: RFC: Query Planner making a distinction between Cross

Ummmm.  Postgresql doesn't natively support cross database queries...

On Thu, 12 Feb 2004, Stef wrote:

> Hey there everyone.
> 
>     Sorry for what seems to be a rather strange
> thought but, could we change the seperator used to
> distinguish 'cross-database' vs 'cross-schema' ?
> 
>     For example, i would expect the following
> to work:
> 
>     CREATE OR REPLACE FUNCTION test_autohist() RETURNS trigger
>     AS 'BEGIN
>             INSERT INTO history.test2 VALUES (new.field1,history.test_hist.nextval(), new.field2, new.field3,
new.field4,new.creation_id, new.creation_date, new.creation_id, new.creation_date);
 
>             RETURN ;
>             END;' LANGUAGE 'plpgsql';
>  
>     CREATE TRIGGER test_autohist_trig
>     AFTER INSERT OR UPDATE ON test
>     FOR EACH ROW
>     EXECUTE PROCEDURE test_autohist();
> 
> 
>     However, when i try it, as far as i can tell,
> the planner parses it down, finds that the schema isnt
> in the current 'search_path' and thus thinks its a cross
> database call.
> 
>     I understand that it may take the planner a 
> while to go through all the available schema's to then
> deduce that it isnt infact a schema at all and return
> the fact that 'cross-database queries are currently not
> implemented', therefore, in the realm of crazy idea, 
> would it be possible to change the notation to reference
> another db ?
> 
>     I was thinking something along the lines of '@',
> but i guess any other non-important ascii character would
> make sense.
> 
>     That way, the planner could decide wether or not
> to attempt a schema resolution (history.table1) or database
> resolution (live@table4).
> 
>     
>     Please note, i am not asking for any sort of 
> 'make cross-database work', merely asking if some sort
> of 'clarification' between cross-database and cross-schema
> would be beneficial. 
> 
>     Ideas ? Comments ? 
> 
>     regards
>     Stef
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 9: the planner will ignore your desire to choose an index scan if your
>       joining column's datatypes do not match
>