The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/10/upgrading.html
Description:
https://www.postgresql.org/docs/10/upgrading.html
It would be helpful to make a note for Linux users that you have login
interactively as the postgres user ie. "sudo -u postgres -i" before running
such commands as "pg_dumpall -p 5432 | psql -d postgres -p 5433". Otherwise
you'll receive the template1 error about the user.
Thanks.