private long calculateSize(long rowNumber, TSDataType[] dataTypes) {
    long size = 0;
    for (int i = 0; i < dataTypes.length; i++) {
      size += getOutputColumnSizePerLine(dataTypes[i]);
    }
    return size * rowNumber;
  }
This Visitor is responsible for transferring PlanNode Tree to Operator Tree.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/planner/OperatorTreeGenerator.java