Date: 2011may25 Updated: 2020apr28 OS: Linux Keywords: postgresql, postgres Q. Postgresql does not understand databases from previous versions How can I upgrade PostgreSQL and keep my data? A. There is finally an easy command for this

postgresql-setup --upgrade

The OLD way... Before upgrading:

cd ~postgres pg_dump database1 > database1.sql (for all databases)

(you really should have other backups)

mv /var/lib/pgsql/data /var/lib/pgsql/data.old

... upgrade ... If you have Postgres 12.1+ upgrade your databases with:

postgresql-setup --upgrade

Otherwise, to restore your data after the upgrade:

cd ~postgres createdb database1 (for all databases) pg_restore -d database1 database1.sql

Then in file /var/lib/pgsql/data/pg_hba.conf I like to change "ident sameuser" to "trust"

# Strict local all all ident sameuser

# Slack local all all trust

To start the service:

postgresql-setup initdb (You have multiple backups, right!)

Or on older systems:

service postgresql initdb (You have multiple backups, right!) systemctl start postgresql

Or on older systems:

service postgresql start

I wish you didn't have to do all this. Mysql will read previous versions of the binary data.