Chapman Flack <chap@anastigmatix.net> writes:
> I've just noticed this in pg_database.dat:
> { oid => '1', oid_symbol => 'TemplateDbOid',
> descr => 'default template for new databases',
> datname => 'template1', ...
> but in the most recent cluster that I pg_upgraded, template1 has oid 16400.
> Nothing is acting broken, but ... is that supposed to happen?
template1 does have OID 1 in a fresh-from-initdb cluster, but it's
just a database; you can drop it and recreate it if you choose.
I believe that pg_upgrade does so.
(Technically, the same applies to template0. But our position on
template0 is that changing the contents of that is unsupported.
So pg_upgrade won't touch the target cluster's version of template0.)
regards, tom lane