Re: snapshot too old issues, first around wraparound and then more.

On Thu, Apr 16, 2020 at 11:37 PM Thomas Munro <thomas.munro@gmail.com> wrote:
> Then of course  frozenXID can be advanced with eg update pg_database
> set datallowconn = 't' where datname = 'template0', then vacuumdb
> --freeze --all, and checked before and after with Robert's
> pg_old_snapshot_time_mapping() SRF to see that it's truncated.  But
> it's not really the level of stuff we'd ideally mess with in
> pg_regress tests and I don't see any precent, so I guess maybe I'll
> need to go and figure out how to write some perl.

The reason I put it in contrib is because I thought it would possibly
be useful to anyone who is actually using this feature to be able to
look at this information. It's unclear to me that there's any less
reason to provide introspection here than there is for, say, pg_locks.

It's sorta unclear to me why you continued the discussion of this on
this thread rather than the new one I started. Seems like doing it
over there might be clearer.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company