On Thu, Oct 21, 2021 at 9:09 AM Joe Conway <m...@joeconway.com> wrote: > I think you are exactly correct. People seem to understand that with a > predicate it is harder, but they expect > > select count(*) from foo; > > to be nearly instantaneous, and they don't really need it to be exact. > The stock answer for that has been to do > > select reltuples from pg_class > where relname = 'foo'; > > But that is unsatisfying because the problem is often with some > benchmark or another that cannot be changed.
I would also expect it to almost always give the wrong answer. -- Robert Haas EDB: http://www.enterprisedb.com
