Re: Serious Performance Loss in 7.0.2?? - Mailing list pgsql-hackers

From Tim Perdue
Subject Re: Serious Performance Loss in 7.0.2??
Date
Msg-id 396CC191.FB042722@valinux.com
Whole thread Raw
In response to Serious Performance Loss in 7.0.2??  (Tim Perdue <tperdue@valinux.com>)
Responses Re: Serious Performance Loss in 7.0.2??  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Tom Lane wrote:
> > As requested by "The Hermit Hacker", I took out the ORDER BY and it was
> > instantaneous.
> 
> How long does it take to do
>         SELECT count(*) FROM tbl_mail_archive WHERE fld_mail_list=35 AND
>         fld_mail_year=2000 AND fld_mail_month=1
> ?  That should tell us how much time is being spent in the indexscan.

It's pretty much instantaneous.

> Also, when you are doing the complete query with sort, does a
> pg_sorttemp file appear in the database directory?  If so, how big does
> it get?

Doesn't look like it. There is a (supposedly) dead pg_sorttemp file in
that directory that is 74MB. Probably unrelated.

My only remaining question is whether an index on 4,000,000 datestamps
is going to be fast or not. Or how Long will my nightly vacuum run?
Forever?

Tim

-- 
Founder - PHPBuilder.com / Geocrawler.com
Lead Developer - SourceForge
VA Linux Systems
408-542-5723


pgsql-hackers by date:

Previous
From: Tom Lane
Date:
Subject: Re: AW: 7.0.2 issues / Geocrawler
Next
From: Tom Lane
Date:
Subject: Re: Serious Performance Loss in 7.0.2??