The catalog pg_user_mapping stores the mappings from local user to remote. Access to this catalog is restricted from normal users, use the view pg_user_mappings instead.
Table 50-57. pg_user_mapping Columns Name Type References Description oid oid Row identifier (hidden attribute; must be explicitly selected) umuser oid pg_authid.oid OID of the local role being mapped, 0 if the user mapping is public umserver oid pg_foreign_server.oid The OID of the foreign server that contains this mapping