Re: SQL/MED - core functionality

On Wed, Dec 22, 2010 at 12:54:06PM -0300, Alvaro Herrera wrote:
> Excerpts from David Fetter's message of mié dic 22 12:36:10 -0300 2010:
> > On Wed, Dec 22, 2010 at 03:00:16PM +0000, Simon Riggs wrote:
> > > On Wed, 2010-12-22 at 09:03 -0500, Andrew Dunstan wrote:
>
> > > > Quite apart from other reasons, such as possible ephemerality of
> > > > the data, the difficulty of taking a reasonable random sample from
> > > > an arbitrary foreign data source seems substantial, and we surely
> > > > don't want ANALYSE to have to run a full sequential scan of a
> > > > foreign data source.
> > >
> > > I think we need something that estimates the size of a table, at
> > > least, otherwise queries will be completely un-optimised.
> >
> > The estimated size for a lot of things--streams of data, for
> > example--is infinity. I suppose that's a good default for some cases.
>
> Since we don't have streaming queries,

We don't, but other systems do.

> this would seem rather pointless ... Surely the FDW must be able to
> limit the resultset somehow.

Using LIMIT. :)

Cheers,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
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