Re: pg_upgrade does not upgrade pg_stat_statements properly

On 2021-Jul-29, Dave Cramer wrote:

> > If the old cluster used extensions those same extensions must be
> > installed in the new cluster via installation procedures specific
> > to, and documented by, each extension.  For contrib extensions it is
> > usually enough to install the -contrib package via the same method
> > you used to install the PostgreSQL server.
>
> Well this is not strictly true. There are many extensions that would
> work just fine with the current pg_upgrade. It may not even be
> necessary to recompile them.

It is always necessary to recompile because of the PG_MODULE_MAGIC
declaration, which is mandatory and contains a check that the major
version matches.  Copying the original shared object never works.