Re: pg_upgrade from 12 to 13 failes with plpython2

[ please don't top-post, it makes conversations unreadable ]

Marcin Giedz <marcin.giedz@arise.pl> writes:
> so look at this: 
> postgres=# drop extension plpython; 
> ERROR: extension "plpython" does not exist 
> postgres=# drop extension plpythonu; 
> ERROR: extension "plpythonu" does not exist 
> postgres=# drop extension plpython2u; 
> ERROR: extension "plpython2u" does not exist 

Well, the pg_upgrade failure clearly shows that you've got some
functions referencing plpython2.  Maybe they're "loose" instead
of being bound into an extension --- that's quite possible if
this database has been brought forward from some pre-9.1 state.
Try looking in each database with

select * from pg_proc where probin like '%python2%';

            regards, tom lane