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From: Greg Smith <greg@2ndquadrant.com>
To: Scott Marlowe <scott.marlowe@gmail.com>
Cc: Marti Raudsepp <marti@juffo.org>
Cc: Kevin Grittner <Kevin.Grittner@wicourts.gov>
Cc: sthomas@peak6.com, Maciek Sakrejda <msakrejda@truviso.com>
Cc: felix <crucialfelix@gmail.com>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: Really really slow select count(*)
Date: Tue, 08 Feb 2011 17:08:25 -0500
Message-ID: <4D51BED9.3000407@2ndquadrant.com> (raw)
In-Reply-To: <AANLkTikFaJsaR_4M8rw4Wwyu_N+5yx2+7MQOZgXPt-kX@mail.gmail.com>
References: <AANLkTinAJcm5A+i1O_R87aiYyu8N2OWgoaL9RfR=tUR9@mail.gmail.com>
	<4D4C138C.7010304@2ndquadrant.com>
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	<AANLkTikrS5JkJDMjAXpcRWRnuLbX+MHB=CWb_mFa9qb-@mail.gmail.com>
	<4D4C2AC3.5020804@peak6.com>
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	<AANLkTim+aLaihKbNSsiiL4exgtCeRqCh_50j48jHFDQm@mail.gmail.com>
	<AANLkTimnFc-hKG+PFEfwBPLAoK6q9kx=nc_4Fr++C_QB@mail.gmail.com>
	<D247E79EFD801E40A9449A9724F6295B0474BBF807@spswchi6mail1.peak6.net>
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	<4D5151C6.7040109@peak6.com>
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	<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>

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




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