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 19:57:54
Message-ID: 20060211195754.GR57845@pervasive.com
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On Sat, Feb 11, 2006 at 07:47:32PM +0000, Simon Riggs wrote:
> On Sat, 2006-02-11 at 11:44 -0600, Jim C. Nasby wrote:
> > 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
>
> Why do that ahead of me making the suggested changes?

Because right now it doesn't say what the actual default is.
--
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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