anchor.diff:             {compaction_histories, StorageStats#storage_stats.compaction_histories},
              {has_error,            StorageStats#storage_stats.has_error}]),
       ok = leo_object_storage_haystack:close(WriteHandler, ReadHandler),
  +    ok = leo_backend_db_server:close(MetaDBId),
       ok.
  
positive.code: %% cleaning up. When it returns, the gen_server terminates with Reason.
  %% The return value is ignored.
  terminate(_Reason, #state{id = Id,
                            state_filepath = StateFilePath,
                            storage_stats  = StorageStats,
                            object_storage = #backend_info{write_handler = WriteHandler,
  
negative.code:     error_logger:info_msg("~p,~p,~p,~p~n",
                            [{module, ?MODULE_STRING}, {function, "terminate/2"},
                             {line, ?LINE}, {body, Id}]),
      ok = close_storage(Id, MetaDBId, StateFilePath,
                         StorageStats, WriteHandler, ReadHandler),
      ok.
  
  