Re: preserving db/ts/relfilenode OIDs across pg_upgrade (was Re: storing an explicit nonce) - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: preserving db/ts/relfilenode OIDs across pg_upgrade (was Re: storing an explicit nonce)
Date
Msg-id 20210824163921.GA21369@momjian.us
Whole thread Raw
In response to Re: preserving db/ts/relfilenode OIDs across pg_upgrade (was Re: storing an explicit nonce)  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Tue, Aug 24, 2021 at 12:04:00PM -0400, Tom Lane wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
> > On Mon, Aug 23, 2021 at 8:29 PM Bruce Momjian <bruce@momjian.us> wrote:
> >> I assume this patch is not going to be applied until there is an actual
> >> use case for preserving these values.
> 
> > ...
> 
> > That being said, if you or somebody else thinks that this is a bad
> > idea or that the reasons offered up until now are insufficient, feel
> > free to make that argument. I just work here...
> 
> Per upthread discussion, it seems impractical to fully guarantee
> that database OIDs match, which seems to mean that the whole premise
> collapses.  Like Bruce, I want to see a plausible use case justifying
> any partial-guarantee scenario before we add more complication (= bugs)
> to pg_upgrade.

Yes, pg_upgrade is already complex enough, so why add more complexity
for some cosmetic value.  (I think "cosmetic" flew out the window with
pg_upgrade long ago.  ;-)  )

I know that pgBackRest has asked for stable relfilenodes to make
incremental file system backups after pg_upgrade smaller, but if we want
to make relfilenodes stable, we had better understand that is _why_ we
are adding this complexity.

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

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




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