Change password for user
sudo -u user_name psql db_nameALTER USER user_name WITH PASSWORD 'new_password';Update password auth method to SCRAM
Edit /etc/postgresql/16/main/postgresql.conf.
password_encryption = scram-sha-256Restart postgresql.service.
At this point, any services using the old MD5 auth method will fail to connect to their PostgreSQL databases.
Update the settings in /etc/postgresql/16/main/pg_hba.conf.
TYPE DATABASE USER ADDRESS METHOD
local all mastodon scram-sha-256
local all synapse_user scram-sha-256Enter a psql shell and determine who needs to upgrade their auth method.
SELECT rolname, rolpassword ~ '^SCRAM-SHA-256\$' AS has_upgraded FROM pg_authid WHERE rolcanlogin;
\password usernameRestart postgresql.service and all services using a PostgreSQL database.