private List<TSDataType> getOutputColumnTypes(PlanNode node, TypeProvider typeProvider) {
    return node.getOutputColumnNames().stream()
        .map(typeProvider::getTreeModelType)
        .collect(Collectors.toList());
  }
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