To: "Sabin Coanda" <sabin.coanda@deuromedia.ro>
cc: pgsql-performance@postgresql.org
Subject: Re: low performance on functions returning setof record 
In-reply-to: <gcl5hg$2kq8$1@news.hub.org> 
References: <gcl5hg$2kq8$1@news.hub.org>
Comments: In-reply-to "Sabin Coanda" <sabin.coanda@deuromedia.ro>
	message dated "Thu, 09 Oct 2008 17:47:30 +0300"
Date: Thu, 09 Oct 2008 15:30:51 -0400
Message-ID: <3693.1223580651@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

"Sabin Coanda" <sabin.coanda@deuromedia.ro> writes:
> I use different functions returning setof record, and they are working well. 
> The problem is the performance when I use those functions in joins, for 
> instance:

>         SELECT *
>         FROM "Table1" t1
>                 JOIN "Function1"( a1, a2, ... aN ) AS f1( ColA int4, ColB 
> varchar, ... )
>                         ON t1.ColX = f1.ColA

> The problem is I'm not able to make indexes on the function, even inside I 
> have just another select statement from different permanent tables, with 
> some where clauses depending on the function arguments.

There's not a lot you can do about that at the moment.  8.4 will have
the ability to inline functions returning sets, if they're SQL-language
and consist of just a single SELECT, but existing releases won't do it.

You might consider trying to refactor your stuff to use views ...

			regards, tom lane