Re: Scrollable cursors and Sort performance

From: "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com>
To: Simon Riggs <simon(at)2ndquadrant(dot)com>
Cc: Martijn van Oosterhout <kleptog(at)svana(dot)org>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Scrollable cursors and Sort performance
Date: 2006-02-11 17:44:35
Message-ID: 20060211174435.GL57845@pervasive.com
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On Sat, Feb 11, 2006 at 11:32:02AM -0600, Jim C. Nasby wrote:
> I think the point that Martijn was trying to make was that per our docs
> it would be perfectly acceptable for us to make any cursor NO SCROLL
> implicitly if it means less work for the optimizer.

Ok, I take that back. The actual quote[1] is:

"Depending upon the complexity of the query's execution plan, specifying
SCROLL may impose a performance penalty on the query's execution time."

Clearly that says it can affect execution time, not that we're free to
alter the default behavior at will.

But speaking of documentation, it doesn't actually say what the default
is. Care update that, or should I formally submit a patch?

[1] http://www.postgresql.org/docs/8.1/interactive/sql-declare.html
--
Jim C. Nasby, Sr. Engineering Consultant jnasby(at)pervasive(dot)com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461

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