@Override
  public Operator visitShowQueries(ShowQueriesNode node, LocalExecutionPlanContext context) {
    OperatorContext operatorContext =
        context
            .getDriverContext()
            .addOperatorContext(
                context.getNextOperatorId(),
                node.getPlanNodeId(),
                ShowQueriesOperator.class.getSimpleName());

    return new ShowQueriesOperator(
        operatorContext, node.getPlanNodeId(), Coordinator.getInstance());
  }
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