Re: Precomputed constants? - Mailing list pgsql-performance

From Jim C. Nasby
Subject Re: Precomputed constants?
Date
Msg-id 20060615155929.GL34196@pervasive.com
Whole thread Raw
In response to Re: Precomputed constants?  (Zoltan Boszormenyi <zboszor@dunaweb.hu>)
Responses Re: Precomputed constants?  (Zoltan Boszormenyi <zboszor@dunaweb.hu>)
List pgsql-performance
On Thu, Jun 15, 2006 at 06:31:02AM +0200, Zoltan Boszormenyi wrote:
> Jim C. Nasby ?rta:
> >On Wed, Jun 14, 2006 at 01:30:10PM +0200, B?sz?rm?nyi Zolt?n wrote:
> >
> >>Replacing random() with a true constant gives me index scan
> >>even if it's hidden inside other function calls. E.g.:
> >>
> >
> >The database has no choice but to compute random() for every row; it's
> >marked VOLATILE.
> >
>
> I see now, docs about CREATE FUNCTION mentions random(),
> currval() and timeofday() as examples for VOLATILE.
> But where in the documentation can I find this info about all
> built-in functions? Thanks.

No, but you can query pg_proc for that info. The docs should have info
about that table.
--
Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.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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