Re: ORDER BY random() LIMIT 1 slowness

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От
Jean-Luc Lachance
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Re: ORDER BY random() LIMIT 1 slowness
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3E00CE39.3CFF7C51@nsd.ca
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Re: ORDER BY random() LIMIT 1 slowness Jean-Luc Lachance <jllachan@nsd.ca>
Alvara,

But instead of returning an error, currval() should return last_value if
nextval() was not called (with all the caveat of couse).  I think it
would be more usefull that way.

JLL


Alvaro Herrera wrote:
> 
> On Wed, Dec 18, 2002 at 02:09:42PM -0500, Jean-Luc Lachance wrote:
> > OK Gabor,
> >
> > I'm the one who misunderstood.
> >
> > To me, it seem to be a bug (or at least a mis-feature) that one cannot
> > call currval() before calling nextval().
> >
> > Does anyone know why it should be like this?
> 
> It doesn't make sense to call currval() if you haven't called nextval()
> before.  The meaning of currval() is "the value that was last assigned
> to you".  If you haven't called nextval(), there isn't a value assigned
> to you.
> 
> If you want to know what was the last value the sequence gave to anyway,
> SELECT last_value FROM sequence.  But be aware that this is
> non-transaction safe, non-isolatable, non-anything.
> 
> --
> Alvaro Herrera ()
> "Entristecido, Wutra
> echa a Freyr a rodar
> y a nosotros al mar" (cancion de Las Barreras)
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