Re: FETCH FIRST clause PERCENT option

On Tue, Mar 26, 2019 at 5:46 PM Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>
wrote:

> On Tue, Mar 26, 2019 at 03:06:52PM +0300, Surafel Temesgen wrote:
> >On Thu, Feb 28, 2019 at 11:16 PM Tomas Vondra <
> tomas(dot)vondra(at)2ndquadrant(dot)com>
> >wrote:
> >
> >>
> >> To give you a (admittedly, somewhat contrived and artificial example):
> >>
> >> SELECT * FROM t1 WHERE id IN (
> >> SELECT id FROM t2 ORDER BY x FETCH FIRST 10 PERCENT ROWS ONLY
> >> );
> >>
> >> Maybe this example is bogus and/or does not really matter in practice. I
> >> don't know, but I've been unable to convince myself that's the case.
> >
> >
> >does this means we abandon incremental approach? and am not sure of
> >calculating
> >percentage after OFFSET clause is acceptable or not
> >
>
> I don't follow. I don't think I've suggested to abandon the incremental
> approach - I've explained why I think it's what the patch should be doing,
> and illustrated that with an example.
>

but it is more complex than the previous approach and it will be more
complex
in starting calculating percentage before offset row count. Doesn't
simplicity prefer?

regards
Surafel