Function typeidTypeRelid

src/backend/parser/parse_type.c:667–681

* Given a typeid, return the type's typrelid (associated relation), if any. * Returns InvalidOid if type is not a composite type. */

 * Returns InvalidOid if type is not a composite type.
 */
Oid
typeidTypeRelid(Oid type_id)
{
	HeapTuple	typeTuple;
	Form_pg_type type;
	Oid			result;

	typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(type_id));
	if (!HeapTupleIsValid(typeTuple))
		elog(ERROR, "cache lookup failed for type %u", type_id);
	type = (Form_pg_type) GETSTRUCT(typeTuple);
	result = type->typrelid;
	ReleaseSysCache(typeTuple);
	return result;
}

/*
 * Given a typeid, return the type's typrelid (associated relation), if any.