Re: Adding skip scan (including MDAM style range skip scan) to nbtree

On Tue, 1 Apr 2025 at 23:56, Matthias van de Meent
<boekewurm+postgres(at)gmail(dot)com> wrote:
>
> On Tue, 1 Apr 2025 at 04:02, Peter Geoghegan <pg(at)bowt(dot)ie> wrote:
> >
> > On Fri, Mar 28, 2025 at 5:59 PM Peter Geoghegan <pg(at)bowt(dot)ie> wrote:
> > > Attached is v32, which has very few changes, but does add a new patch:
> > > a patch that adds skip-array-specific primitive index scan heuristics
> > > to _bt_advance_array_keys (this is
> > > v32-0003-Improve-skip-scan-primitive-scan-scheduling.patch).
> >
> > Attached is v33
>
> 0001:
>
> I just realised we never check whether skip keys' high/low_compare
> values generate valid quals, like what you'd see generated for WHERE a
> > 5 AND a < 3 AND b = 2;
>
> This causes a performance regression in the patched version:

Apparently it's not a regression, as we don't have this check in place
in the master branch. So, that's an optimization for PG19.

Sorry for the noise.

Kind regards,

Matthias van de Meent
Neon (https://neon.tech)