On Sat, Oct 07, 2017 at 05:44:00AM +0200, Pavel Stehule wrote: > 2017-10-06 21:36 GMT+02:00 Nico Williams <nico@cryptonector.com>: > > But the nice thing about them is that you need only create them once, so > > leave them in the catalog. Stats about them should not be gathered nor > > stored, since they could be different per-session. > > Unfortunately one field from pg_class are not static - reltuples should be > per session.
It's "only an estimate" "used by the query planner". We could estimate zero for global temp tables, and the query planner can get the true value from an internal temp table.