Message-ID: <4FCE1160.4070003@optionshouse.com>
Date: Tue, 5 Jun 2012 09:02:08 -0500
From: Shaun Thomas <sthomas@optionshouse.com>
Reply-To: <sthomas@optionshouse.com>
Organization: Peak6
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To: Andrew Jaimes <andrewjaimes@hotmail.com>
CC: Postgres Performance <pgsql-performance@postgresql.org>
Subject: Re: Sequencial scan in a JOIN
References: <BLU161-W1125BE7D5AED110518DEFFDD0C0@phx.gbl>,
	<4FCE0681.5040306@optionshouse.com>
	<BLU161-W5750D54FD724EB2412564CDD0C0@phx.gbl>
In-Reply-To: <BLU161-W5750D54FD724EB2412564CDD0C0@phx.gbl>
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On 06/05/2012 08:31 AM, Andrew Jaimes wrote:

> the default_statistics_target is set to 200, and I have run the analyze
> and reindex on these tables before writing the email.

Out of idle curiosity, how do these two variants treat you?

SELECT count(1)
   FROM e_usersessions s
   JOIN l_userqueue q ON (q.userid = s.entityid)
   JOIN a_activity a ON (a.activequeueid = q.queueid)
  WHERE s.sessionkeepalivedatetime > 20120605082131943
    AND a.vstatus        = 1
    AND a.ventrydate     > 0
    AND a.sbuid          = s.sbuid
    AND a.assignedtoid   = 0
    AND a.status        <> '0'

SELECT count(1)
   FROM e_usersessions s
   JOIN l_userqueue q ON (q.userid = s.entityid)
  WHERE s.sessionkeepalivedatetime > 20120605082131943
    AND EXISTS (
          SELECT 1 FROM a_activity a
           WHERE a.activequeueid = q.queueid
             AND a.sbuid         = s.sbuid
             AND a.vstatus       = 1
             AND a.ventrydate    > 0
             AND a.assignedtoid  = 0
             AND a.status       <> '0'
        )

-- 
Shaun Thomas
OptionsHouse | 141 W. Jackson Blvd. | Suite 500 | Chicago IL, 60604
312-444-8534
sthomas@optionshouse.com

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