Postgresql: Read-Only User

create user xxxxx with password 'yyyy';
GRANT connect ON DATABASE mydb1 TO xxxxx;
GRANT connect ON DATABASE mydb2 TO xxxxx;

\c mydb1
GRANT usage ON SCHEMA public TO xxxxx;
GRANT select ON ALL TABLES IN SCHEMA public TO xxxxx;
GRANT select ON ALL SEQUENCES IN SCHEMA public TO xxxxx;

\c mydb2
GRANT usage ON SCHEMA public TO xxxxx;
GRANT select ON ALL TABLES IN SCHEMA public TO xxxxx;
GRANT select ON ALL SEQUENCES IN SCHEMA public TO xxxxx;