@Override
  public Comparator comparator() {
    if (data instanceof NWayMergeResults.NWayMergeResultsCollection) {
      return ((NWayMergeResultsCollection) data).comparator;
    } else {
      return null;
    }
  }
The n - way merge results returns a sorted results on the cumulative sorted results for
partitioned region based query
geode-core/src/main/java/org/apache/geode/cache/query/internal/NWayMergeResults.java