To: "Dai, Tino" <tdai@loc.gov>
cc: "pgsql-admin@postgresql.org" <pgsql-admin@postgresql.org>
Subject: Re: Disparity between 8.1.18 and 8.2.14 performance wise 
In-reply-to: <1CA7FF980DA3824F9A5C31532B7A40DCC4B87E10@LCXCLMB01.LCDS.LOC.GOV>
References: <1CA7FF980DA3824F9A5C31532B7A40DCC4B87E10@LCXCLMB01.LCDS.LOC.GOV>
Comments: In-reply-to "Dai, Tino" <tdai@loc.gov>
	message dated "Mon, 22 Mar 2010 17:58:41 -0400"
Date: Mon, 22 Mar 2010 19:07:35 -0400
Message-ID: <16222.1269299255@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

"Dai, Tino" <tdai@loc.gov> writes:
> After many days of googling and referring to different web pages about performance, I'm
> turning to this list for help. We have a third party application that is running on 8.1.11 and the
> vendor has told us not to upgrade the database to 8.2. 

8.2 was released in 2006.  8.1 is going to be desupported entirely at
the end of 2010.  You really need to be holding your vendor's feet to
the fire about supporting modern versions of Postgres, rather than
looking for workarounds.

But having said that, I think 8.1 might generate a reasonable plan if it
weren't getting misled by these useless constraints:

>                ->  Seq Scan on role_setting  (cost=0.00..964.50 rows=1 width=70) (actual time=0.036..121.443 rows=43833 loops=1)
>                      Filter: (((section)::text = (section)::text) AND (ref_id = ref_id))

Can you get rid of those?

			regards, tom lane