这个警告不会影响数据库的访问 但是当有大量的这种日志产生的时候，数据库之前的错误信息 就会很难去查询了。连接数越多，产生报警日志的频率越高。
数据库的alert.log中，我们经常会出现下面的警告:
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IP address '172.16.12.195' could not be resolved: Temporary failure in name resolution IP address '172.16.12.67' could not be resolved: Temporary failure in name resolution IP address '172.16.12.67' could not be resolved: Temporary failure in name resolution IP address '172.16.12.195' could not be resolved: Temporary failure in name resolution IP address '172.16.12.195' could not be resolved: Temporary failure in name resolution IP address '172.16.12.195' could not be resolved: Temporary failure in name resolution IP address '172.16.12.196' could not be resolved: Temporary failure in name resolution IP address '172.16.12.196' could not be resolved: Temporary failure in name resolution IP address '172.16.12.195' could not be resolved: Temporary failure in name resolution IP address '172.16.12.195' could not be resolved: Temporary failure in name resolution IP address '172.16.12.68' could not be resolved: Temporary failure in name resolution |
出现错误的原因是MYSQL Server在本地内存中维护了一个非本地的Client TCP cache，这个cache中包含了远程Client的登录信息，比如IP地址，hostname等信息。
如果Client连接到服务器后，Mysql首先会在本地TCP池中根据IP地址解析客户端的hostname或者反解析，如果解析不到，就会去DNS中进行解析，如果还是解析失败
就是在error log中写入这样的警告信息。
可以通过两个参数来disable这个功能，在MYSQL的配置文件中[mysqld]中加入下面的参数:
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[mysqld] --skip-host-cache --skip-name-resolve |
重新授权，将所有访问数据库服务器的授权方式都改成IP形式的。
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grant all on *.* to ‘root’@’172.16.12.68’identified by ‘123456’; |
将所有访问数据库服务器的授权方式都改成IP形式。
不同的用户用不同的用户名和密码。
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grant all on *.* to ‘user_68’@’172.16.12.68’identified by ‘pwd_68’; grant all on *.* to ‘user_67’@’172.16.12.67’identified by ‘pwd_67’; .... |
然后去 mysql数据库下面的 user表 和db表 下面删除掉那些含有含有主机名字的权限记录。
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--skip-host-cache --skip-name-resolve |
使得MySQL将不再通过DNS解析地址。
要么在赋予权限的时候 直接用ip地址，去掉那些用主机名字的权限。
from:http://www.uedsc.com/ip-address-could-not-be-resolved.html