@Override
  public Object runOnRange(int rowNum, Range range, VectorPTFGroupBatches batches) {
    count = range.getEnd() - range.getStart();
    return count;
  }
This class evaluates count(*) for a PTF group.

Count all rows of the group.  No input column/expression.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/ptf/VectorPTFEvaluatorCountStar.java