final BasicOperator oldRoot = evaluator.getRootNode();
final Result oldResult = evaluator.getResultOperator();
final Map<Variable, Integer> oldBindingsFactory = evaluator.getBindingsFactory().getPosVariables();
final Root collectionClone = (Root) collection.deepClone();
collectionClone.visit(new SimpleOperatorGraphVisitor() {
;
@Override
public Object visit(final BasicOperator basicOperator) {
if (basicOperator instanceof BasicIndexScan) {