@Override
    public String toString() {
      return String.format("PartitionResults (evaluators: %d, rows: %d): %s", results.length,
          results[0].length, Arrays.deepToString(results));
    }
Used for keeping track of iterations on results.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/ptf/VectorPTFGroupBatches.java