Create a readonly user in Postgres

This is quite useful to create a user that can be used for backups, reporting and so on.

Assuming you have databases foo_db and bar_db and want to create a readonly user for them called backup_user with password qux94874:

CREATE USER backup_user WITH ENCRYPTED PASSWORD 'qux94874';
GRANT CONNECT ON DATABASE foo_db to backup_user;
GRANT CONNECT ON DATABASE bar_db to backup_user;
\c foo
GRANT USAGE ON SCHEMA public to backup_user;
GRANT SELECT ON ALL SEQUENCES IN SCHEMA public TO backup_user;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO backup_user;
\c bar
GRANT USAGE ON SCHEMA public to backup_user;
GRANT SELECT ON ALL SEQUENCES IN SCHEMA public TO backup_user;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO backup_user;