On Wed, Jan 25, 2023 at 7:56 PM Andres Freund <andres@anarazel.de> wrote:
> > https://wiki.postgresql.org/wiki/Freezing/skipping_strategies_patch:_motivating_examples#Patch_2
> >
> > The difference between this and VACUUM FREEZE is described here:
> >
> > "Note how we freeze most pages, but still leave a significant number
> > unfrozen each time, despite using an eager approach to freezing
> > (2981204 scanned - 2355230 frozen = 625974 pages scanned but left
> > unfrozen). Again, this is because we don't freeze pages unless they're
> > already eligible to be set all-visible.
>
> The only reason there is a substantial difference is because of pgbench's
> uniform access pattern. Most real-world applications don't have that.
It's not pgbench! It's TPC-C. It's actually an adversarial case for
the patch series.
--
Peter Geoghegan