} else if (orderByKey) {
TupleExpMemoComparator comp =
new HierarchicalTupleKeyComparator(
evaluator, key.key, arity);
comp.preloadValues(tupleList);
chain.addComparator(comp, key.direction.descending);
} else {
TupleExpComparator comp =
new HierarchicalTupleComparator(
evaluator, key.key, arity, key.direction.descending);
chain.addComparator(comp, false);