private static long getDaughterRegionIdTimestamp(final RegionInfo hri) {
    long rid = EnvironmentEdgeManager.currentTime();
    // Regionid is timestamp. Can't be less than that of parent else will insert
    // at wrong location in hbase:meta (See HBASE-710).
    if (rid < hri.getRegionId()) {
      LOG.warn("Clock skew; parent regions id is " + hri.getRegionId()
        + " but current time here is " + rid);
      rid = hri.getRegionId() + 1;
    }
    return rid;
  }
Calculate daughter regionid to use.
@param hri Parent {@link RegionInfo}
@return Daughter region id (timestamp) to use.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/SplitTableRegionProcedure.java