Re: Teach pg_upgrade to deal with invalid databases - Mailing list pgsql-hackers

Hi,

On Fri, Oct 2, 2026 at 9:21 AM Nathan Bossart <nathandbossart@gmail.com> wrote:
>
> On Thu, Sep 24, 2026 at 08:37:00AM -0700, Bharath Rupireddy wrote:
> > I implemented the above approach, pg_upgrade skipping them without any
> > option and emitting info about the skipped ones. I ensured the CI is
> > happy. Please find the attached v2 patch.
>
> Thanks.  IMHO we shouldn't bother adding a note to pg_upgrade's
> documentation, or even emitting warnings when pg_upgrade skips invalid
> databases.  For all intents and purposes, the database is already dropped
> (for some definition of "dropped"), and there's nothing actionable for the
> user.

Thanks for looking at it.

Upon thinking more on this, I agree on both. Unless there are
objections, I will drop the warning and the doc note in the next
version.

Once pg_upgrade skips invalid databases, the user has no action to
take. Even if the user reverts to the old cluster, the invalid
databases are still there.

I also think not reporting them matches what other tools do, like
pg_dumpall (dumpDatabases()), vacuumdb (vacuum_all_databases()),
reindexdb (reindex_all_databases()), etc. They skip invalid databases
without emitting any info, and their docs don't mention it either.

--
Bharath Rupireddy
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