@Override
  public boolean isDeviceAlive(IDeviceID device, long ttl) {
    return ttl == Long.MAX_VALUE || endTime >= CommonDateTimeUtils.currentTime() - ttl;
  }
end times. The value is Long.MIN_VALUE if it's an unsealed sequence tsfile
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/tsfile/timeindex/FileTimeIndex.java