Re: Call for objections: simplify stable functions during estimation

On Tuesday 09 November 2004 11:28, Tom Lane wrote:
> Awhile back, there was some discussion about pre-folding now() and
> related functions when the planner is trying to estimate selectivities.
> This would allow reasonable plans to be made for cases like
> WHERE moddate >= current_date - 10;
> without having to indulge in any crude hacks with mislabeled wrapper
> functions, such as you can find all too often in the archives :-(
>
> I was a bit hesitant about it at the time because I wasn't sure of all
> the implications; but I've looked the idea over again, and as far as I
> can see it's reasonable to pre-fold *all* stable functions when deriving
> statistical estimates. (One of the potential objections went away when
> we started enforcing that stable functions don't have side-effects.)
>

Since we know people will be calling volatile functions inside stable
functions (see thread from last week if you need a refresher as to why) is
there any serious negative side-effect in those cases?

--
Robert Treat
Build A Brighter Lamp :: Linux Apache {middleware} PostgreSQL