Re: preserving db/ts/relfilenode OIDs across pg_upgrade (was Re: storing an explicit nonce)

On Tue, Aug 24, 2021 at 12:43:20PM -0400, Bruce Momjian wrote:
> Yes, it is a trade-off.  If we had pg_upgrade create the new cluster,
> the pg_upgrade instructions would be simpler, but pg_upgrade would be
> more complex since it has to adjust _everything_ properly so pg_upgrade
> works --- I never got to that point, but I am willing to explore what
> would be required.

One other issue --- the more that pg_upgrade preserves, the more likely
pg_upgrade will break when some internal changes happen in Postgres. 
Therefore, if you want pg_upgrade to preserve something, you have to
have a good reason --- even code simplicity might not be a sufficient
reason.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  If only the physical world exists, free will is an illusion.