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From: Andrew Dunstan <andrew@dunslane.net>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Heikki Linnakangas <hlinnakangas@vmware.com>
Cc: Craig Ringer <craig@2ndQuadrant.com>
Cc: Claudio Freire <klaussfreire@gmail.com>
Cc: Merlin Moncure <mmoncure@gmail.com>
Cc: David Greco <David_Greco@harte-hanks.com>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: Poor performance using CTE
Date: Wed, 21 Nov 2012 10:21:16 -0500
Message-ID: <50ACF16C.2020902@dunslane.net> (raw)
In-Reply-To: <3396.1353509947@sss.pgh.pa.us>
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	<50ACD166.1000507@vmware.com>
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	<3396.1353509947@sss.pgh.pa.us>


On 11/21/2012 09:59 AM, Tom Lane wrote:
> Andrew Dunstan <andrew@dunslane.net> writes:
>> If we're going to do it can we please come up with something more
>> intuitive and much, much more documented than "OFFSET 0"? And if/when we
>> do this we'll need to have big red warnings all over then release notes,
>> since a lot of people I know will need to do some extensive remediation
>> before moving to such a release.
> The probability that we would actually *remove* that behavior of OFFSET
> 0 is not distinguishable from zero.  I'm not terribly excited about
> having an alternate syntax to specify an optimization fence, but even
> if we do create such a thing, there's no need to break the historical
> usage.
>

I wasn't talking about removing it. My point was that if the 
optimization fence around CTEs is removed a lot of people will need to 
rework apps where they have used them for that purpose. And I continue 
to think that spelling it "OFFSET 0" is horribly obscure.

cheers

andrew




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