@Override
  public int estimateSize() {
    return 8 + 8;
  }
The memory occupied by an DatabaseDeviceInfo based occupation

<ol>
  <li>object header, 8B
  <li>long dataTTL, 8B
</ol>
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/schemaengine/schemaregion/mtree/impl/mem/mnode/info/DatabaseInfo.java