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
