@Override
  public Operator visitGroup(GroupNode node, LocalExecutionPlanContext context) {
    StreamSortNode streamSortNode =
        new StreamSortNode(
            node.getPlanNodeId(),
            node.getChild(),
            node.getOrderingScheme(),
            false,
            false,
            node.getPartitionKeyCount() - 1);
    return visitStreamSort(streamSortNode, context);
  }
This Visitor is responsible for transferring Table PlanNode Tree to Table Operator Tree.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/planner/TableOperatorGenerator.java