Re: [PATCH] Fix division by zero (explain.c)

Em sáb., 9 de mai. de 2020 às 17:48, Tomas Vondra <
tomas(dot)vondra(at)2ndquadrant(dot)com> escreveu:

> On Sat, May 09, 2020 at 02:51:50PM -0300, Ranier Vilela wrote:
> >Em sáb., 9 de mai. de 2020 às 14:44, Tomas Vondra <
> >tomas(dot)vondra(at)2ndquadrant(dot)com> escreveu:
> >
> >> On Sat, May 09, 2020 at 06:48:59AM -0300, Ranier Vilela wrote:
> >> >Em sáb., 9 de mai. de 2020 às 01:45, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
> >> escreveu:
> >> >
> >> >> James Coleman <jtc331(at)gmail(dot)com> writes:
> >> >> > There are always full sort groups before any prefix groups can
> happen,
> >> >> > so we know (even though the tooling doesn't) that the 2nd test can
> >> >> > never contradict the first.
> >> >>
> >> >> So maybe an assertion enforcing that would be appropriate?
> >> >> Untested, but:
> >> >>
> >> >> - if (fullsortGroupInfo->groupCount == 0 &&
> >> >> - prefixsortGroupInfo->groupCount == 0)
> >> >> + if (fullsortGroupInfo->groupCount == 0)
> >> >> + {
> >> >> +
> Assert(prefixsortGroupInfo->groupCount
> >> ==
> >> >> 0);
> >> >> continue;
> >> >> + }
> >> >>
> >> >I agree, asserts always help.
> >> >
> >>
> >> That doesn't work, because the prefixSortGroupInfo is used before
> >> assignment, producing compile-time warnings.
> >>
> >> I've pushed a simpler fix without the assert. If we want to make this
> >> check, perhaps doing it in incremental sort itself would be better than
> >> doing it in explain.
> >>
> >Thanks anyway for the commit.
> >But if you used the first version of my patch, would the author be me and
> >am I as reported?
> >What does it take to be considered the author?
> >
>
> Apologies. I should have listed you as an author, not just in the
> reported-by field.
>
Apologies accepted.

Thank you.

Ranier VIilela