Re: BUG #17066: Cache lookup failed when null (unknown) is passed as anycompatiblemultirange

On Tue, Jun 22, 2021 at 7:01 PM Alexander Korotkov <aekorotkov@gmail.com> wrote:
> On Tue, Jun 22, 2021 at 4:42 PM Alvaro Herrera <alvherre@2ndquadrant.com> wrote:
> > On 2021-Jun-22, Neil Chen wrote:
> >
> > > Greetings,
> > >
> > > I tried to investigate the bug, but the complicated logic here completely
> > > messed up my mind...
> > >
> > > Anyway, this patch can fix it and make the regress test happy. But I think
> > > it's better to get the author's advice - I copied this email to Alvaro,
> > > hope it doesn't offend him...
> >
> > Without looking too deeply, the patch seems sensible to me.  However,
> > I'm CC'ing Alexander and Paul :-)
>
> Thank you for pointing this out.  And thanks to Neil for the fix.
>
> Looks good at the first glance.  I'm going to review this in the next
> couple of days.

I've reviewed enforce_generic_type_consistency() more carefully.  It
looks for me that this function requires more significant rework.  For
instance, these two functions throw errors, but it seems that both of
them should work.

create function multirange_func(r anycompatiblerange)
  returns anycompatiblemultirange as 'select multirange($1);' language sql;
create function range_func(r anycompatiblemultirange)
  returns anycompatiblerange as 'select multirange($1);' language sql;

# select multirange_func(int4range(1,10));
ERROR:  could not identify anycompatiblemultirange type

# select range_func(int4multirange(int4range(1,10)));
ERROR:  could not determine polymorphic type anycompatiblerange
because input has type unknown

So, I'm still investigating this.

------
Regards,
Alexander Korotkov