'Used in replication to handle updating timestamps.
:param created_at: create timestamp
:param put_timestamp: put timestamp
:param delete_timestamp: delete timestamp'

def merge_timestamps(self, created_at, put_timestamp, delete_timestamp):

    with self.get() as conn:
        old_status = self._is_deleted(conn)
        conn.execute(('\n                                                                UPDATE    %s_stat    SET    created_at=MIN(?,    created_at),\n                                                                                                                                            put_timestamp=MAX(?,    put_timestamp),\n                                                                                                                                            delete_timestamp=MAX(?,    delete_timestamp)\n                                                ' % self.db_type), (created_at, put_timestamp, delete_timestamp))
        if (old_status != self._is_deleted(conn)):
            timestamp = Timestamp.now()
            self._update_status_changed_at(conn, timestamp.internal)
        conn.commit()
