Re: Odd 9.4, 9.3 buildfarm failure on s390x

On 2018-10-01 12:13:57 -0400, Tom Lane wrote:
> Andres Freund <andres(at)anarazel(dot)de> writes:
> > On 2018-10-01 11:58:51 -0400, Tom Lane wrote:
> >> Oooh ... apparently, on that platform, memcmp() is willing to produce
> >> INT_MIN in some cases. That's not a safe value for a sort comparator
> >> to produce --- we explicitly say that somewhere, IIRC.
>
> > Hm, that'd be pretty painful - memcmp() isn't guaranteed to return
> > anything smaller. And we use memcmp in a fair number of comparators.
>
> Yeah. So our choices are
>
> (1) Retain the current restriction on what sort comparators can
> produce. Find all the places where memcmp's result is returned
> directly, and fix them. (I wonder if strcmp has same issue.)
>
> (2) Drop the restriction. This'd require at least changing the
> DESC correction, and maybe other things. I'm not sure what the
> odds would be of finding everyplace we need to check.
>
> Neither one is sounding very pleasant, or maintainable.

(2) seems more maintainable to me (or perhaps less unmaintainable). It's
infrastructure, rather than every datatype + support out there...

Greetings,

Andres Freund