Re: pg_upgrade does not upgrade pg_stat_statements properly

On Thu, Jul 29, 2021 at 05:01:24PM -0400, Tom Lane wrote:
> Dave Cramer <davecramer(at)gmail(dot)com> writes:
> > So back to the original motivation for bringing this up. Recall that a
> > cluster was upgraded. Everything appeared to work fine, except that the
> > definitions of the functions were slightly different enough to cause a
> > fatal issue on restoring a dump from pg_dump.
> > Since pg_upgrade is now part of the core project, we need to make sure this
> > is not possible or be much more insistent that the user needs to upgrade
> > any extensions that require it.
>
> TBH, this seems like mostly the fault of the extension author.
> The established design is that the SQL-level objects will be
> carried forward verbatim by pg_upgrade. Therefore, any newer-version
> shared library MUST be able to cope sanely with SQL objects from
> some previous revision. The contrib modules provide multiple
> examples of ways to do this.
>
> If particular extension authors don't care to go to that much
> trouble, it's on their heads to document that their extensions
> are unsafe to pg_upgrade.

I think we need to first give clear instructions on how to find out if
an extension update is available, and then how to update it. I am
thinking we should supply a query which reports all extensions that can
be upgraded, at least for contrib.

--
Bruce Momjian <bruce(at)momjian(dot)us> https://momjian.us
EDB https://enterprisedb.com

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