pg_user_mapping

The system catalog table pg_user_mapping stores the mappings from local user to remote user. You must have administrator privileges to view this catalog. Access to this catalog is restricted from normal users, use the pg_user_mappings view instead.

column	type	references	description
oid	oid		The object ID
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	OID of the foreign server that contains this mapping
umoptions	text[]		User mapping-specific options, as "keyword=value" strings.

Parent topic: System Catalogs Definitions