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安装mysql 5.5以上的经常会发现网站访问不到数据库

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Jun 07, 2016 pm 04:20 PM

mysqlDiscoverInstalldatabasewebsiteaccess

mysql宕机主要有两个原因： 1.内存被其它进程大量占用，或数据库本身数据量太大导致mysql宕机 2.程序访问mysql后没有执行mysql.close，大量占用资源导致宕机。群里提出的这个问题主要是mysql5.5以上的，基本上不是mysql宕机。因为5.5以上的数据库会有个链接

mysql宕机主要有两个原因：

1.内存被其它进程大量占用，或数据库本身数据量太大导致mysql宕机
2.程序访问mysql后没有执行mysql.close，大量占用资源导致宕机。

群里提出的这个问题主要是mysql5.5以上的，基本上不是mysql宕机。因为5.5以上的数据库会有个链接超时配置。
默认是28800秒也就是8个小时，会断开连接。
解决方案：
1.修改mysql配置。
如果是linux服务器编辑mysql.cnf 执行vi /etc/mysql.cnf
找到[mysqld] 在底下添加
interactive_timeout=28800000
wait_timeout=28800000
多加了三个0 也就是8000个小时。基本就不用考虑连接超时
修改完配置后，记得重启mysql服务。

2.程序方面。

以java程序为例(抱歉只会java)
打开Spring配置文件，，修改applicationContext.xml
在datasource bean底下添加
用来指定测试连接所使用的SQL语句。
如果测试发现连接已经close，那么将自动重建连接。

SELECT 1

用来指定在使用连接之前要进行测试。

true

Statement

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