void updateRegionMaximumEditLogSeqNum(WAL.Entry entry) {
    synchronized (regionMaximumEditLogSeqNum) {
      String regionName = Bytes.toString(entry.getKey().getEncodedRegionName());
      Long currentMaxSeqNum = regionMaximumEditLogSeqNum.get(regionName);
      if (currentMaxSeqNum == null || entry.getKey().getSequenceId() > currentMaxSeqNum) {
        regionMaximumEditLogSeqNum.put(regionName, entry.getKey().getSequenceId());
      }
    }
  }
Update region's maximum edit log SeqNum.
hbase-server/src/main/java/org/apache/hadoop/hbase/wal/AbstractRecoveredEditsOutputSink.java