private ICachedMNode getNode(ICachedMNode root, String path) throws MetadataException {
    String[] pathNodes = PathUtils.splitPathToDetachedNodes(path);
    ICachedMNode cur = root;
    for (String node : pathNodes) {
      if (!node.equals("root")) {
        cur = cur.getChild(node);
      }
    }
    return cur;
  }
related methods shall be merged further: {@linkplain SchemaFile#reEstimateSegSize}
,{@linkplain PageManager#reEstimateSegSize}
iotdb-core/datanode/src/test/java/org/apache/iotdb/db/metadata/mtree/schemafile/SchemaFileTest.java