Re: Precomputed constants?

[Zoltan Boszormenyi <zboszor(at)dunaweb(dot)hu>]

Jim C. Nasby írta:
> 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.
>   

Thanks!

# select proname,provolatile from pg_proc where proname='random';
proname | provolatile
---------+-------------
random  | v
(1 sor)

# select distinct provolatile from pg_proc;
provolatile
-------------
i
s
v
(3 sor)

If I get this right, IMMUTABLE/STABLE/VOLATILE
are indicated with their initials.

Best regards,
Zoltán Böszörményi