Re: Precomputed constants?

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