pg.ddx.io  pgsql-performance@postgresql.org mailing list archive  

help / color / mirror / Atom feed
From: Shaun Thomas <sthomas@peak6.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Josh Berkus <josh@agliodbs.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Postgres refusing to use >1 core
Date: Thu, 12 May 2011 11:11:21 -0500
Message-ID: <4DCC06A9.9020509@peak6.com> (raw)
In-Reply-To: <18068.1305216474@sss.pgh.pa.us>
References: <BANLkTimohiUa6rOYdxYTwqmvSUg2CRYMHg@mail.gmail.com>
	<4DC81A3F020000250003D433@gw.wicourts.gov>
	<BANLkTimNTLqQgQeyu=FPOn-5x6F4XnVBJA@mail.gmail.com>
	<4DC81D56020000250003D438@gw.wicourts.gov>
	<BANLkTi=FH4rX-7OtS9ozjuyXQTNTiRqCmg@mail.gmail.com>
	<BANLkTinwkj7syvKkYzU_O7DD14EMzk2Zmg@mail.gmail.com>
	<BANLkTi=BvGMvsBNq8DUt=_MPJXZjcC0TWg@mail.gmail.com>
	<4DC8B893.3060908@postnewspapers.com.au>
	<BANLkTimi+2nviLvWU4zKGtG688+Z84DF6w@mail.gmail.com>
	<4DC9E7C5.9080309@postnewspapers.com.au>
	<BANLkTi=PxROPQFDt1a6N68e_+5_AojagmA@mail.gmail.com>
	<4DCAB3A1.2090507@peak6.com>
	<201105111953.060147@ms14.lnh.mail.rcn.net>
	<4DCB0802.9060505@peak6.com>
	<4DCB346E.8070608@agliodbs.com>
	<15686.1305211902@sss.pgh.pa.us>
	<4DCC0167.8080903@peak6.com>
	<18068.1305216474@sss.pgh.pa.us>

On 05/12/2011 11:07 AM, Tom Lane wrote:

> I find it odd that replacing the subquery with a temp table helps,
> though, because (unless you stuck in an ANALYZE you didn't mention)
> it would have no stats at all about the number of groups in the temp
> table.

I did have an analyze initially for exactly that reason. But what I 
found odd is that in my rush to execute this for the end of day reports, 
I forgot that step, and it still ran fine. I've found that the planner 
tends to treat un-analyzed tables somewhat pessimistically, which is 
fine by me.

-- 
Shaun Thomas
OptionsHouse | 141 W. Jackson Blvd. | Suite 800 | Chicago IL, 60604
312-676-8870
sthomas@peak6.com

______________________________________________

See  http://www.peak6.com/email_disclaimer.php
for terms and conditions related to this email



view thread (46+ messages)  latest in thread

Message-ID: <4DCC06A9.9020509@peak6.com>
Permalink:  ../4DCC06A9.9020509@peak6.com/
Also on:    postgresql.org/message-id/4DCC06A9.9020509@peak6.com

 · 

reply
Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-performance@postgresql.org
  Cc: sthomas@peak6.com, tgl@sss.pgh.pa.us, josh@agliodbs.com
  Subject: Re: Postgres refusing to use >1 core
  In-Reply-To: <4DCC06A9.9020509@peak6.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox