public RelOptCost plus(RelOptCost other) {
    if ((this == INFINITY) || (other.isInfinite())) {
      return INFINITY;
    }
    return new HiveCost(this.rowCount + other.getRows(), this.cpu + other.getCpu(), this.io
        + other.getIo());
  }
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