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

help / color / mirror / Atom feed
From: Josh Berkus <josh@agliodbs.com>
To: pgsql-performance@postgresql.org
Subject: Re: 7k records into Sort node, 4.5m out?
Date: Wed, 15 Aug 2012 14:02:35 -0700
Message-ID: <502C0E6B.1040402@agliodbs.com> (raw)
In-Reply-To: <16268.1345063872@sss.pgh.pa.us>
References: <D2CA9292-023A-4DF4-82B8-6E99CE82CCB1@thebuild.com>
	<dda48e8e4cd63cc6f98f9eca78016c05.squirrel@sq.gransy.com>
	<32B51AEA-E940-40CF-BA54-C7D4E3E1F0D7@thebuild.com>
	<10304.1344910305@sss.pgh.pa.us>
	<623F2FF3-B79D-419A-929A-41C707DD5EA3@thebuild.com>
	<16268.1345063872@sss.pgh.pa.us>

On 8/15/12 1:51 PM, Tom Lane wrote:
> Christophe Pettus <xof@thebuild.com> writes:
>> On Aug 13, 2012, at 7:11 PM, Tom Lane wrote:
>>> The whole thing looks a bit weird to me --- why did it not use a
>>> nestloop join with inner indexscan on charlie?  With 7000 rows on the
>>> other side, the estimated cost for that shouldn't have been more than
>>> about 30000 ...
> 
>> Here's the same query with set enable_megejoin = off.  All of the other query tuning parameters are default.
> 
>> 	http://explain.depesz.com/s/dqO
> 
> Maybe you had better show us the actual query, and the table/index
> definitions.  Because it's sure making odd choices here.  This seems
> like the wrong join order altogether ...

We'll need to do that off-list for confidentiality reasons.


-- 
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com




view thread (13+ messages)  latest in thread

Message-ID: <502C0E6B.1040402@agliodbs.com>
Permalink:  ../502C0E6B.1040402@agliodbs.com/
Also on:    postgresql.org/message-id/502C0E6B.1040402@agliodbs.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: josh@agliodbs.com
  Subject: Re: 7k records into Sort node, 4.5m out?
  In-Reply-To: <502C0E6B.1040402@agliodbs.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