The pg_auth_members system catalog table shows the membership relations between roles. Any non-circular set of relationships is allowed. Because roles are system-wide, pg_auth_members is shared across all databases of a HAWQ system.

Table 1. pg_catalog.pg_auth_members

column type references description
roleid oid pg_authid.oid ID of the parent-level (group) role
member oid pg_authid.oid ID of a member role
grantor oid pg_authid.oid ID of the role that granted this membership
admin_option boolean   True if role member may grant membership to others