Re: BUG #19098: Can't create unique gist index, where pg_indexes says that WITHOUT OVERLAPS does exacly that

On Fri, 31 Oct 2025 at 13:52, Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> wrote:
>
> On Thu, 2025-10-30 at 14:31 -0400, Tom Lane wrote:
> > Paul A Jungwirth <pj(at)illuminatedcomputing(dot)com> writes:
> > > So here is a proposed sequence of work:
> > >
> > > - Add an opclass_parameter so you can say without_overlaps = true.
> > > Only the last column of the index allows that (at least for now), and
> > > there must be an overlaps operator.
> > > - If an index has that property, enforce the exclusion constraint
> > > rules and forbid empty ranges/multiranges.
> > > - Update pg_get_indexdef to output the right syntax to create an
> > > independent temporal index.
> >
> > > Doing the first 3 items here would fix pg_get_indexdef. The hard one
> > > is the second, but I will work on a patch for it. Is that something
> > > we'd want to release as a patch to v18?
> >
> > I think that's too much risk and churn for v18 at this point.
> > Even if we risked putting in such a patch, we'd have a situation
> > where pg_get_indexdef in later v18 minor releases would output
> > syntax that's rejected by earlier minor releases, which would
> > be a mess.
> >
> > My feeling is that pg_get_indexdef is broken for these indexes, but
> > there's nothing we can do now to improve that in v18. The important
> > thing is to make sure it gets fixed for 19.
>
> One thing we could do is have pg_get_indexdef() throw an error rather
> than producing wrong output.
>
> Yours,
> Laurenz Albe
>

Yep, errcode(FEATURE_NOT_SUPPORTED) here may be a lesser evil compared
to others.

--
Best regards,
Kirill Reshke