Postgresql usage notes

Revoke:

    REVOKE ALL ON DATABASE db_name FROM user_name;
    revoke all on all tables in schema public from zabbix;

Readonly User:

    revoke all on schema public from public;
    create role zabbix login password 'some_pass';
    grant usage on schema public to zabbix;
    grant select on public.some_table to zabbix;

When you create a new database, any role is allowed to create objects in the public schema. To remove this possibility, you may issue immediately after the database creation:

REVOKE ALL ON schema public FROM public;

Edit: after the above command, only a superuser may create new objects inside the public schema, which is not practical. Assuming a non-superuser foo_user should be granted this privilege, this should be done with:

GRANT ALL ON schema public TO foo_user;