On Wed, Nov 20, 2019 at 1:43 PM Peter Geoghegan wrote:
> My understanding is that we can trust RecentGlobalXmin to be something
> useful and current during recovery, in general, so the selfuncs.c
> index-only scan (which uses SnapshotNonVacuumable + RecentGlobalXmin)
> can be trusted to work just
I noticed that the nbtree README has an obsolete reference to the
former design of get_actual_variable_range() in the "Scans during
Recovery" section. It used to use a dirty snapshot, but doesn't
anymore. These days, get_actual_variable_range() uses
SnapshotNonVacuumable -- see commits 3ca930fc and
