MySQL 已经设置了 skip-name-resolve，但还会出现 unauthenticated user 信息，是什么原因 ？
mysql> show full processlist;
+-----+----------------------+--------------------+------+---------+------+----------------------------------+-----------------------+
| Id | User | Host | db | Command | Time | State | Info |
+-----+----------------------+--------------------+------+---------+------+----------------------------------+-----------------------+
| 1 | system user | | NULL | Connect | 623 | Waiting for master to send event | NULL |
| 2 | system user | | NULL | Connect | 0 | Reading event from the relay log | NULL |
| 585 | root | localhost | dd | Query | 0 | NULL | show full processlist |
| 748 | unauthenticated user | 2.191.10.27:32833 | NULL | Connect | NULL | login | NULL |
| 749 | unauthenticated user | 2.191.10.27:32836 | NULL | Connect | NULL | login | NULL |
……
| 799 | unauthenticated user | 2.191.10.139:46877 | NULL | Connect | NULL | login | NULL |
| 800 | unauthenticated user | 2.191.10.139:46879 | NULL | Connect | NULL | login | NULL |
+-----+----------------------+--------------------+------+---------+------+----------------------------------+-----------------------+
556 rows in set (0.00 sec)