@Override
  public MeasurementPath fetchMeasurementPath(PartialPath fullPath) throws MetadataException {
    IMeasurementMNode<ICachedMNode> node = mtree.getMeasurementMNode(fullPath);
    try {
      MeasurementPath res = new MeasurementPath(node.getPartialPath(), node.getSchema());
      res.setUnderAlignedEntity(node.getParent().getAsDeviceMNode().isAligned());
      return res;
    } finally {
      mtree.unPinMNode(node.getAsMNode());
    }
  }
Get device node, if the schema region is not set, create it when autoCreateSchema is true

<p>(we develop this method as we need to get the node's lock after we get the lock.writeLock())

@param path path
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/schemaengine/schemaregion/impl/SchemaRegionPBTreeImpl.java