@Override
  public boolean updateDatabaseNode(IDatabaseMNode<ICachedMNode> sgNode) throws IOException {
    this.isEntity = sgNode.isDevice();
    if (sgNode.isDevice()) {
      this.sgNodeTemplateIdWithState = sgNode.getAsDeviceMNode().getSchemaTemplateIdWithState();
    }
    updateHeaderBuffer();
    return true;
  }
This class is mainly aimed to manage space all over the file.

<p>This class is meant to open a .pst(Persistent mTree) file, and maintains the header of the
file. It Loads or writes a page length bytes at once, with an 32 bits int to index a page inside
a file. Use SlottedFile to manipulate segment(sp) inside a page(an array of bytes).
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/schemaengine/schemaregion/mtree/impl/pbtree/schemafile/SchemaFile.java