Re: Calculation of unused columns

On Mon, 2009-10-19 at 13:43 -0400, Tom Lane wrote:
> Simon Riggs <simon@2ndQuadrant.com> writes:
> > On Sat, 2009-10-17 at 21:41 -0400, Tom Lane wrote:
> >> one thing we'd have to consider
> >> is whether it is okay to suppress calculation of columns containing
> >> volatile functions.
>
> > I think we should have a 4th class of functions,
> > volatile-without-side-effects (better name needed, obviously).
>
> What for?  There wouldn't be that many, I think.  random() and
> clock_timestamp(), yeah, but most volatile user-defined functions
> are either volatile-with-side-effects or misdeclared.

Read only vs. read write?

--
 Simon Riggs           www.2ndQuadrant.com