From: Gregory Stark <stark@enterprisedb.com>
To: "Adriaan van Os" <postgres@microbizz.nl>
Cc: <pgsql-performance@postgresql.org>
Subject: Re: TRUNCATE TABLE
In-Reply-To: <46972DFA.9000900@microbizz.nl> (Adriaan van Os's message of
	"Fri, 13 Jul 2007 09:47:06 +0200")
Organization: EnterpriseDB
References: <46953949.3030201@microbizz.nl>
	<87ps2ypox3.fsf@oxford.xeocode.com> <46972DFA.9000900@microbizz.nl>
Date: Fri, 13 Jul 2007 10:02:33 +0100
Message-ID: <87tzs865hy.fsf@oxford.xeocode.com>
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"Adriaan van Os" <postgres@microbizz.nl> writes:

> That's a remarkable advice, because XFS is known to be slow at creating and
> deleting files, see <http://en.wikipedia.org/wiki/XFS> and
> <http://everything2.com/index.pl?node_id=1479435>.

I think this is a case of "you're both right". XFS may have to do more work
than other filesystems for meta-information updates. However It still only has
to do a constant or nearly constant amount of work. So it may be slower at
managing a large directory of thousands of small files than ext3, but it's
faster at deleting a single 1G file than ext3.

On mythtv the experience is that if you use ext3 and delete a large file while
recording another program you can expect the new recording to lose stutter at
that point. The large delete will lock out the recording from writing to the
filesystem for several seconds.

-- 
  Gregory Stark
  EnterpriseDB          http://www.enterprisedb.com