docs: protected Pair<KNNQuery<O>, KNNQuery<O>> getKNNQueries(Database database, Relation<O> relation, StepProgress stepprog) {
      KNNQuery<O> knnComp, knnReach;
      if(comparisonDistanceFunction == reachabilityDistanceFunction || comparisonDistanceFunction.equals(reachabilityDistanceFunction)) {
        LOG.beginStep(stepprog, 1, "Materializing neighborhoods with respect to reference neighborhood distance function.");
        knnComp = DatabaseUtil.precomputedKNNQuery(database, relation, comparisonDistanceFunction, MathUtil.max(kcomp, kreach) + 1);
        knnReach = knnComp;
      }
      else {
        LOG.beginStep(stepprog, 1, "Not materializing distance functions, since we request each DBID once only.");
        knnComp = QueryUtil.getKNNQuery(relation, comparisonDistanceFunction, kreach + 1);
        knnReach = QueryUtil.getKNNQuery(relation, reachabilityDistanceFunction, kcomp + 1);
      }
      return new Pair<>(knnComp, knnReach);
    }