51.9. pg_auth_members #
 The catalog pg_auth_members shows the membership relations between roles. Any non-circular set of relationships is allowed. 
 Because user identities are cluster-wide, pg_auth_members is shared across all databases of a cluster: there is only one copy of pg_auth_members per cluster, not one per database. 
Table 51.9. pg_auth_members Columns
Column Type Description  | 
|---|
 Row identifier  | 
 ID of a role that has a member  | 
  ID of a role that is a member of   | 
 ID of the role that granted this membership  | 
  True if   | 
 True if the member automatically inherits the privileges of the granted role  | 
  True if the member can   |