public IntoPathIterator getIntoPathIterator() {
    return new IntoPathIterator(
        intoItems, isDeviceExistPlaceholder(), isMeasurementsExistPlaceholder());
  }
This class maintains information of {@code INTO} clause.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/statement/component/IntoComponent.java