@Override
          public void generateCurrentDeviceOperatorTree(DeviceEntry deviceEntry) {
            calculateSeriesScanOptionsList();
            operator = constructTreeToTableViewAdaptorOperator(deviceEntry);
            if (isSingleColumn) {
              return;
            }
            if (!cannotPushDownConjuncts.isEmpty()
                || node.getAssignments().size() != node.getOutputSymbols().size()) {
              operator = getFilterAndProjectOperator(operator);
            }
            if (!node.isPushLimitToEachDevice() || removeUpperOffsetAndLimitOperator) {
              return;
            }
            if (node.getPushDownLimit() > 0) {
              operator = new LimitOperator(operatorContext, node.getPushDownLimit(), operator);
            }
          }
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