@Override
public QueryResult process(final QueryResult bindings, final int operandID) {
SortConfiguration sortConfiguration = new SortConfiguration();
sortConfiguration.useExternalMergeSort();
final DBMergeSortedBag<Bindings> bag = new DBMergeSortedBag<Bindings>(
sortConfiguration, new Comparator<Bindings>() {
public int compare(final Bindings arg0, final Bindings arg1) {
for (final Variable var : sortCriterium) {