mysql 日志中出现Forcing close of thread XXX user: 'XXX'

MySql新手

MySQL总是隔段时间就停掉，查看日志，里面出现几行warning警告
170612 18:19:40 [Note] Server hostname (bind-address): '0.0.0.0'; port: 3306
170612 18:19:40 [Note]   - '0.0.0.0' resolves to '0.0.0.0';
170612 18:19:40 [Note] Server socket created on IP: '0.0.0.0'.
170612 18:19:40 [Warning] 'proxies_priv' entry '@ root@ipv6-1-13.localdomain' ignored in --skip-name-resolve mode.
170612 18:19:40 [Note] Event Scheduler: Loaded 0 events
170612 18:19:40 [Note] /usr/local/mysql/bin/mysqld: ready for connections.
Version: '5.5.42'  socket: '/tmp/mysql.sock'  port: 3306  Source distribution
170612 18:46:11 [Note] /usr/local/mysql/bin/mysqld: Normal shutdown

170612 18:46:11 [Note] Event Scheduler: Purging the queue. 0 events
170612 18:46:13 [Warning] /usr/local/mysql/bin/mysqld: Forcing close of thread 175  user: 'root'

170612 18:46:13 [Warning] /usr/local/mysql/bin/mysqld: Forcing close of thread 174  user: 'root'

170612 18:46:13 [Warning] /usr/local/mysql/bin/mysqld: Forcing close of thread 173  user: 'root'

170612 18:46:13 [Warning] /usr/local/mysql/bin/mysqld: Forcing close of thread 172  user: 'root'

170612 18:46:13 [Warning] /usr/local/mysql/bin/mysqld: Forcing close of thread 169  user: 'root'

170612 18:46:13 [Warning] /usr/local/mysql/bin/mysqld: Forcing close of thread 163  user: 'root'
在网上查了好多，大部分都说是dns解析问题，可我的配置文件已经配置了skip-external-locking
skip-name-resolve 这两个参数了，小弟实在是不知道该怎么解决了，所以就在此发帖请求各位大神。
哪位好心的大神能帮忙一下，看看出现该情况的原因。小弟不胜感谢