Re: pg_upgrade from 12 to 13 failes with plpython2

On Wed, Nov 18, 2020 at 09:35:20PM -0700, Rob Sargent wrote:
> > pg_upgrade does have some code to handle plpython call handlers in
> > function.c:get_loadable_libraries();
> > 
> >         * Systems that install plpython before 8.1 have
> >         * plpython_call_handler() defined in the "public" schema, causing
> >         * pg_dump to dump it.  However that function still references
> >         * "plpython" (no "2"), so it throws an error on restore.  This code
> >         * checks for the problem function, reports affected databases to the
> >         * user and explains how to remove them. 8.1 git commit:
> >         * e0dedd0559f005d60c69c9772163e69c204bac69
> >         * http://archives.postgresql.org/pgsql-hackers/2012-03/msg01101.php
> >         * http://archives.postgresql.org/pgsql-bugs/2012-05/msg00206.php
> > 
> > -- 
> >  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
> >  EnterpriseDB                             https://enterprisedb.com
> > 
> >  The usefulness of a cup is in its emptiness, Bruce Lee
> > 
> > 
> Unless it stop at prompts for “Yes, ok, I understand.” this could easily fly out the window.

It issues this message and fails:

            if (PQntuples(res) > 0)
            {
                if (!found_public_plpython_handler)
                {
                    pg_log(PG_WARNING,
                           "\nThe old cluster has a \"plpython_call_handler\" function defined\n"
                           "in the \"public\" schema which is a duplicate of the one defined\n"
                           "in the \"pg_catalog\" schema.  You can confirm this by executing\n"
                           "in psql:\n"
                           "\n"
                           "    \\df *.plpython_call_handler\n"
                           "\n"
                           "The \"public\" schema version of this function was created by a\n"
                           "pre-8.1 install of plpython, and must be removed for pg_upgrade\n"
                           "to complete because it references a now-obsolete \"plpython\"\n"
                           "shared object file.  You can remove the \"public\" schema version\n"
                           "of this function by running the following command:\n"
                           "\n"
                           "    DROP FUNCTION public.plpython_call_handler()\n"
                           "\n"
                           "in each affected database:\n"
                           "\n");
                }
                pg_log(PG_WARNING, "    %s\n", active_db->db_name);
                found_public_plpython_handler = true;
            }
            PQclear(res);
        }

        PQfinish(conn);
    }

    if (found_public_plpython_handler)
        pg_fatal("Remove the problem functions from the old cluster to continue.\n");


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

  The usefulness of a cup is in its emptiness, Bruce Lee