The view pg_user provides access to
   information about database users.  This is simply a publicly
   readable view of 
   pg_shadow
   that blanks out the password field.
  
Table 42-45. pg_user Columns
| Name | Type | References | Description | 
|---|
| usename | name |   | User name | 
| usesysid | int4 |   | User ID (arbitrary number used to reference this user) | 
| usecreatedb | bool |   | User may create databases | 
| usesuper | bool |   | User is a superuser | 
| usecatupd | bool |   |        User may update system catalogs.  (Even a superuser may not do
       this unless this column is true.)
       | 
| passwd | text |   | Not the password (always reads as ********) | 
| valuntil | abstime |   | Password expiry time (only used for password authentication) | 
| useconfig | text[] |   | Session defaults for run-time configuration variables |