The catalog pg_authid contains information about database authorization identifiers (roles). A role subsumes the concepts of "users" and "groups". A user is essentially just a role with the rolcanlogin flag set. Any role (with or without rolcanlogin) can have other roles as members; see pg_auth_members.
Since this catalog contains passwords, it must not be publicly readable. pg_roles is a publicly readable view on pg_authid that blanks out the password field.
Chapter 19 contains detailed information about user and privilege management.
Because user identities are cluster-wide, pg_authid is shared across all databases of a cluster: there is only one copy of pg_authid per cluster, not one per database.
Table 44-8. pg_authid Columns
| Name | Type | Description |
|---|---|---|
| rolname | name | Role name |
| rolsuper | bool | Role has superuser privileges |
| rolinherit | bool | Role automatically inherits privileges of roles it is a member of |
| rolcreaterole | bool | Role can create more roles |
| rolcreatedb | bool | Role can create databases |
| rolcatupdate | bool | Role can update system catalogs directly. (Even a superuser cannot do this unless this column is true) |
| rolcanlogin | bool | Role can log in. That is, this role can be given as the initial session authorization identifier |
| rolconnlimit | int4 | For roles that can log in, this sets maximum number of concurrent connections this role can make. -1 means no limit |
| rolpassword | text | Password (possibly encrypted); NULL if none |
| rolvaliduntil | timestamptz | Password expiry time (only used for password authentication); NULL if no expiration |
| rolconfig | text[] | Session defaults for run-time configuration variables |