public static TreeDeviceSchemaCacheManager getInstance() {
    return TreeDeviceSchemaCacheManagerHolder.INSTANCE;
  }
This class takes the responsibility of metadata cache management of all DataRegions under
StorageEngine
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/relational/metadata/fetcher/cache/TreeDeviceSchemaCacheManager.java