从MySQL 5.x的某个版本之后，MySQL的自动关闭空闲连接的特性被修改了，假如一个连接空闲到超时时间(默认28000秒8小时)，再次发起
最近碰到了这个问题，检查后发现MySQL数据库连接池中保存的连接超时后失效了，下面是官方的解释
从MySQL 5.x的某个版本之后，MySQL的自动关闭空闲连接的特性被修改了，假如一个连接空闲到超时时间(默认28000秒8小时)，再次发起的Reconnect重新连接请求不会被接受，需要重新建立新连接，这就导致了SER的重连机制不能正常工作：SER只会在需要操作数据库时去使用同一个连接接口，断开了则发起重新连接请求，而且这个问题短期内SER也不能够解决。
下文中将具体讲述处理的方法：
1.使用Mysql 4.0或4.1版本，如果没有用到Mysql 5的一些新特性比如存储过程触发器之类。
2.定时重启Mysql服务器或Ser(由于本问题可能同样会影响到其它一些需要Mysql支持的服务器程序，所以重启Mysql服务器为好，但需要检测Mysql服务器不被使用的一个时间重启比较难确定)
3.设置my.cnf，有mysqld字段内增加参数：
[mysqld]port = 3306socket = /tmp/mysql.sockwait_timeout= 500000interactive_timeout = 500000(500000秒约五六天的超时时间，可根据实际需要选择一个数据库可能空闲的最长时间稍大的时间值。)重启Mysqld应用即可，也可以在执行mysqld时加-o wait_timeout=500000参数同样效果。
在MySQL客户端show variable时应该可以看到最后一条从默认的wait_time=28000变成500000了。
(假如重启Mysqld不生效，，可以重启机子)
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