Re: Teach pg_upgrade to deal with invalid databases

On Tue, Sep 08, 2026 at 10:11:23AM -0700, Bharath Rupireddy wrote:
> pg_upgrade skipping the invalid databases seems like the right
> approach. Whether or not this has to be put behind an option and
> retain the current error behavior is something we need to agree on. I
> still think pg_upgrade can just skip and the error could be removed,
> unless anyone thinks otherwise.

I think we ought to simply skip the invalid databases without any sort of
option. The only counterargument I'm aware of is that someone might want
to try recoving the database, but AFAIK there's no supported recovery
mechanism. Even if there was, it seems pretty unlikely that a user would
cancel an errant DROP DATABASE and then proceed to run pg_upgrade before
attempting recovery. Furthermore, I believe the proposed skipping behavior
more closely matches the previous behavior before we started using
datconnlimit == -2 to mean the database is invalid.

--
nathan