Re: FETCH FIRST clause PERCENT option

On 2018-08-21 15:47:07 +0300, Surafel Temesgen wrote:
> On Thu, Aug 16, 2018 at 5:34 PM, Andres Freund <andres@anarazel.de> wrote:
> 
> >
> > Won't that have rather massive issues with multiple evaluations of
> > clauses in the query?  Besides being really expensive?
> >
> The plan re-scane after first execution I can’t see issue for multiple
> execution of a clause in this case

Imagine volatile functions being used. That can be problematic because
of repeated side-effects, but also will lead to plainly wrong
results. Consider what happens with your approach where somebody does
something like WHERE value < random().

Greetings,

Andres Freund