From: Michael Stone <mstone+postgres@mathom.us>
To: pgsql-performance@postgresql.org
Subject: Re: insert vs select into performance
Date: Wed, 18 Jul 2007 07:31:43 -0400
Message-ID: <20070718113141.GH12481@mathom.us> (raw)
In-Reply-To: <469D2D59.9030106@ifi.uio.no>
References: <469D1AD3.9030004@ifi.uio.no>
<0D6011B2-D09F-45E8-A5D7-5F84ADD1DC2B@seespotcode.net>
<5666.1184704280@sss.pgh.pa.us>
<469D2D59.9030106@ifi.uio.no>
On Tue, Jul 17, 2007 at 10:58:01PM +0200, Thomas Finneid wrote:
>I am not sure I understand you correctly here, are you saying that
>SELECT INTO in 8.1 disables WAL logging and uses just a single fsync at
>the end? in that case it means that I could disable WAL as well and
>achieve the same performance, does it not?
Yes. The difference is that the select into optimization just means that
if the system crashes the data you're inserting is invalid (and is
properly cleaned up), and disabling the WAL means that if the system
crashes everything is invalid (and can't be cleaned up).
Mike Stone
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To: pgsql-performance@postgresql.org
Cc: mstone+postgres@mathom.us
Subject: Re: insert vs select into performance
In-Reply-To: <20070718113141.GH12481@mathom.us>
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