mySQL 错误日志分析
https://github.com/twitter/mysql/commit/1912d02a461797977219e2578080b790020ad845
https://github.com/twitter/mysql/blob/master/sql/hostname.cc
错误：
130111 3:33:55 [Warning] IP address '74.86.110.133' has been resolved to the host name '74.86.110.133-static.reverse.softlayer.com', which resembles IPv4-address itself.
130111 4:00:00 [Note] /usr/sbin/mysqld: Normal shutdown
130111 4:00:00 [Note] Event Scheduler: Purging the queue. 0 events
130111 4:00:02 [Warning] /usr/sbin/mysqld: Forcing close of thread 410210 user: 'root'
http://dev.mysql.com/doc/refman/5.5/en/host-cache.html DNS 高速缓存 问题
http://dev.mysql.com/doc/refman/5.5/en/blocked-host.html 解决方案
SET GLOBAL max_connect_errors=10000;
错误日志有类似警告：
120119 16:26:04 [Warning] IP address '192.168.0.110' could not be resolved: Name or service not known
120119 16:26:04 [Warning] IP address '192.168.0.104' could not be resolved: Name or service not known
120119 16:26:04 [Warning] IP address '192.168.0.147' could not be resolved: Name or service not known
通过show processlist发现大量类似如下的连接：
|592|unauthenticated user|192.168.3.20:35320|NULL|Connect| |login|NULL|
|593|unauthenticated
user|192.168.3.20:35321|NULL|Connect| |login|NULL|
|594|unauthenticated user|192.168.3.20:35322|NULL|Connect|
|login|NULL|
skip-name-resolve 参数的目的是不再进行反解析（ip不反解成域名），这样可以加快数据库的反应时间。
修改配置文件添加并需要重启：
[mysqld]
skip-name-resolve
添加后发现错误日志有
120203 10:21:06 [Warning] 'user' entry
'root@r590ubuntu' ignored in --skip-name-resolve mode.
120203 10:21:06 [Warning] 'user' entry '@r590ubuntu' ignored in
--skip-name-resolve mode.
只需去服务器里边把用户root@r590ubuntu和@r590ubuntu删除即可。
错误:
:57 [Note] Flashcache bypass: disabled
130116 20:14:57 [Note] Flashcache setup error is : ioctl failed
地址: http://bugs.mysql.com/bug.php?id=64927
130201 3:29:07 [Warning] IP address '222.217.223.49' could not be resolved: Temporary failure in name resolution
http://blog.csdn.net/lxpbs8851/article/details/7892256
解决方案:
[mysqld]
--skip-host-cache
--skip-name-resolve
