I'm not too familiar with the innards of pg_upgrade, but we've been discussing it a lot for past couple of days and how it's causing issues for PostGIS upgrades.
I think this thread covers most of the issues. https://lists.osgeo.org/pipermail/postgis-devel/2017-August/026355.html My thought was is it possible for pg_upgrade to be taught to use CREATE EXENSION if asked? Right now we don't support PostgreSQL 11 on PostGIS 2.3 and we really would like not to because there are too many changes done in 11 that we feel queezy about backporting. Even if we did, package maintainers would have to provide 2.3 on 11 and 2.4 on 11 just so people can pg_upgrade to PostgreSQL 11 and then ALTER EXTESNION postgis UPDATE; To postgis 2.4.0 Given that latest PostgreSQL 11 head already doesn't compile against PostGIS 2.4, I'm not confident we can fix 2.4 for 11. So this will continue to be more of a problem especially at the rate that PostgreSQL is changing these days. Right now crafty users have to do something like this to use pg_upgrade https://gist.github.com/Komzpa/994d5aaf340067ccec0e My solution of let's not call it postgis-2.4 but just postgis-2 from thenceforward for the life of 2 major series because we don't break backward compatibility often in a PostGIS minor version got shot down. Any thoughts on this? Thanks, Regina Obe PostGIS PSC member -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers