Received: from maia.hub.org (maia-5.hub.org [200.46.204.29])
	by mail.postgresql.org (Postfix) with ESMTP id 7208B1336B42
	for <pgsql-performance-postgresql.org@mail.postgresql.org>;
	Tue,  8 Feb 2011 18:08:42 -0400 (AST)
Received: from mail.postgresql.org ([200.46.204.86])
	by maia.hub.org (mx1.hub.org [200.46.204.29]) (amavisd-maia, port 10024)
	with ESMTP id 43347-06
	for <pgsql-performance-postgresql.org@mail.postgresql.org>;
	Tue,  8 Feb 2011 22:08:36 +0000 (UTC)
X-Greylist: from auto-whitelisted by SQLgrey-1.7.6
Received: from moutng.kundenserver.de (moutng.kundenserver.de [212.227.17.8])
	by mail.postgresql.org (Postfix) with ESMTP id AB27C1336971
	for <pgsql-performance@postgresql.org>;
	Tue,  8 Feb 2011 18:08:34 -0400 (AST)
Received: from [192.168.1.6] (mail.highperformancepostgresql.com
	[71.179.240.8])
	by mrelayeu.kundenserver.de (node=mrbap1) with ESMTP (Nemesis)
	id 0MWhPH-1PcDHE1ri7-00XdFF; Tue, 08 Feb 2011 23:08:28 +0100
Message-ID: <4D51BED9.3000407@2ndquadrant.com>
Date: Tue, 08 Feb 2011 17:08:25 -0500
From: Greg Smith <greg@2ndquadrant.com>
User-Agent: Thunderbird 2.0.0.24 (X11/20100317)
MIME-Version: 1.0
To: Scott Marlowe <scott.marlowe@gmail.com>
CC: Marti Raudsepp <marti@juffo.org>,
	Kevin Grittner <Kevin.Grittner@wicourts.gov>,
	sthomas@peak6.com, Maciek Sakrejda <msakrejda@truviso.com>,
	felix <crucialfelix@gmail.com>,
	"pgsql-performance@postgresql.org" <pgsql-performance@postgresql.org>
Subject: Re: Really really slow select count(*)
References: <AANLkTinAJcm5A+i1O_R87aiYyu8N2OWgoaL9RfR=tUR9@mail.gmail.com>
	<4D4C138C.7010304@2ndquadrant.com>	<4D4C1555.40209@peak6.com>
	<AANLkTikrS5JkJDMjAXpcRWRnuLbX+MHB=CWb_mFa9qb-@mail.gmail.com>
	<4D4C2AC3.5020804@peak6.com>
	<AANLkTin8ndBSU9ZJ2uAdnvYQ7oLBg2S04bqAXn-s5qv+@mail.gmail.com>
	<AANLkTim+aLaihKbNSsiiL4exgtCeRqCh_50j48jHFDQm@mail.gmail.com>
	<AANLkTimnFc-hKG+PFEfwBPLAoK6q9kx=nc_4Fr++C_QB@mail.gmail.com>
	<D247E79EFD801E40A9449A9724F6295B0474BBF807@spswchi6mail1.peak6.net>
	<AANLkTiknh-snZvy4_PzS9CgVfNCH3RTS+V=COWVOnTNo@mail.gmail.com>
	<4D5151C6.7040109@peak6.com>
	<AANLkTinaaVonows3OzN3dVNZQyqhLMVYv8M0Y0Cg73H_@mail.gmail.com>
	<4D511C99020000250003A62D@gw.wicourts.gov>
	<AANLkTi=uh-zScT=LcYQ6kXDXCpmMZoAeiO4hqk0=WWSt@mail.gmail.com>
	<4D51A304.4070003@2ndquadrant.com>
	<AANLkTikFaJsaR_4M8rw4Wwyu_N+5yx2+7MQOZgXPt-kX@mail.gmail.com>
In-Reply-To: <AANLkTikFaJsaR_4M8rw4Wwyu_N+5yx2+7MQOZgXPt-kX@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
X-Provags-ID: V02:K0:avpNw3gEK6AtNxGCFQ/JIGxjGvtBYksVRjHVOxPhw5L
	f4CPoAvQvzNf3I2x63C7yzRjLvUQgeBRkYqXy6uCKbULi4/gbD
	NL72UoVZAE/IeVzYYafsIc5W7AOYiQR5/dsMh0oBIJokjulPY5
	rJ9CsNtaZ9rh7Gk2nCtsMiB3xPgHI3NrvT1gHUCovs0zrBgpru
	hq9JM8uCgg0Nv8+UY/VHhO3vHLtkZxA+2LAiyzWeVg=
X-Virus-Scanned: Maia Mailguard 1.0.1
X-Spam-Status: No, hits=-1.9 tagged_above=-10 required=5 tests=BAYES_00=-1.9,
	RCVD_IN_DNSWL_NONE=-0.0001
X-Spam-Level: 
X-Archive-Number: 201102/319
X-Sequence-Number: 42457

Scott Marlowe wrote:
> Are there any settings in postgresql.conf that would make it unsafe to
> use -m immediate?
>   

Two concerns:

-Clients will be killed without any review, and data related to them lost

-The server will have to go through recovery to start back up again, 
which could potentially take a long time.  If you manage a successful 
shutdown that doesn't happen.

Shouldn't be unsafe, just has those issues.

-- 
Greg Smith   2ndQuadrant US    greg@2ndQuadrant.com   Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support  www.2ndQuadrant.us
"PostgreSQL 9.0 High Performance": http://www.2ndQuadrant.com/books