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To: "Kevin Grittner" <Kevin.Grittner@wicourts.gov>
cc: jd@commandprompt.com, "Greg Stark" <gsstark@mit.edu>,
	"Robert Haas" <robertmhaas@gmail.com>, "Bruce Momjian" <bruce@momjian.us>,
	"Michael Tharp" <gxti@partiallystapled.com>, pgsql-hackers@postgresql.org,
	"Craig Ringer" <craig@postnewspapers.com.au>
Subject: Re: no universally correct setting for fsync 
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Comments: In-reply-to "Kevin Grittner" <Kevin.Grittner@wicourts.gov>
	message dated "Mon, 10 May 2010 14:00:37 -0500"
Date: Mon, 10 May 2010 15:57:42 -0400
Message-ID: <16370.1273521462@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
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"Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
> Perhaps Josh's language for fsync could be modified to work here
> (we're now talking about full_page_writes, for anyone who's lost
> track):
 
> | it is only advisable to turn off fsync if you can easily recreate
> | your entire database from external data.

> That covers bulk loads to an empty or just-backed-up database and
> entirely redundant databases.  Saying it should never be turned off
> would tend to make one wonder why we have the setting at all.

+1.  Perhaps for both of them, we should specify that the intended
use-case is for improving performance during initial database load
and similar cases.

			regards, tom lane