Re: amcheck support for BRIN indexes

On Mon, Jul 7, 2025 at 3:21 PM Álvaro Herrera <alvherre(at)kurilemu(dot)de> wrote:
>
> On 2025-Jul-07, Tomas Vondra wrote:
>
> > Alvaro, what's your opinion on the introduction of the new WITHIN_RANGE?
> > I'd probably try to do this using the regular consistent function:
> >
> > (a) we don't need to add stuff to all BRIN opclasses to support this
> >
> > (b) it gives us additional testing of the consistent function
> >
> > (c) building a scan key for equality seems pretty trivial
> >
> > What do you think?
>
> Oh yeah, if we can build this on top of the existing primitives, then
> I'm all for that.

Thank you for the feedback! I agree with the benefits. Speaking of
(с), it seems most of the time to be really trivial to build such a
ScanKey, but not every opclass supports '=' operator. amcheck should
handle these cases somehow then. I see two options here. The first is
to not provide 'heap all indexed' check for such opclasses, which is
sad because even one core opclass (box_inclusion_ops) doesn't support
'=' operator, postgis brin opclasses don't support it too AFAICS. The
second option is to let the user define which operator to use during
the check, which, I think, makes user experience much worse in this
case. So both options look not good from the user POV as for me, so I
don't know. What do you think about it?

And should I revert the patchset to the consistent function version then?

Best regards,
Arseniy Mukhin