@Override
  public String toString() {
    return "{" + rowCount + " rows, " + cpu + " cpu, " + io + " io}";
  }
NOTE:<br>
1. HiveCost normalizes cpu and io in to time.<br>
2. CPU, IO cost is added together to find the query latency.<br>
3. If query latency is equal then row count is compared.
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/cost/HiveCost.java