On Fri, Aug 22, 2025 at 11:20 PM Fujii Masao <masao.fu...@gmail.com> wrote:
> On Sat, Aug 23, 2025 at 12:00 PM Nathan Bossart > <nathandboss...@gmail.com> wrote: > > > > On Sat, Aug 23, 2025 at 10:59:43AM +0900, Fujii Masao wrote: > > > I tested by creating many tables with make installcheck and running > > > vacuumdb --missing-stats-only on the regression database. > > > Without the patch, the query to find tables to analyze took about 60 > ms, > > > but with the patch it took 18 seconds. That seems too slow, > > > so probably we'll need to tune the query? > Sounds exactly like the issue we encountered with queries that used pg_stats in pg_dump. > > > > Hm. Maybe we should just document that the option requires SELECT > > privileges on pg_statistic and pg_statistic_ext_data (which are > restricted > > to superusers by default). I suspect we have relatively limited > > opportunities for tuning the query, and I'd like to avoid invasive > changes > > to v18 at this point. > > Yeah, adding a note about the permissions required for > --missing-stats-only, > leaving the query unchanged in v18, and revisiting the issue in v19 seems > reasonable given the limited time before the v18 release. > Rather than resorting to the redundant where-clause trick that we did in pg_dump. Looking to v19, I think the problem could be solved if we exposed starelid in pg_stats and stxrelid in pg_stats_ext and joined on those. pg_dump would benefit from that as well, eventually.
