docs: function debug(rusage, memory) {
    var dbs = this._store.databases
      , i
      , db
      , size;
    for(i in dbs) {
      db = dbs[i];
      size = db.dbsize();
      if(size) {
        this._logger.debug('DB %s: %s keys (%s volatile)', i, size, db.expiring);
      }
    }
    this._logger.debug('%s clients connected, %s heap, %s rss bytes',
      this.getLength(), memory.heapUsed, rusage.maxrss);
  }