首先，我们看下
show GLOBAL VARIABLES like '%timeout%';
默认值为28800s即8小时,我们改为100s
# Default Homebrew MySQL server config
[mysqld]
# Only allow connections from localhost
bind-address = 0.0.0.0
wait_timeout=100
interactive_timeout=100
重新查看结果
查看对守护进程连接的影响
public function longT()
{
$TicketModel = new TicketModel();
$this->success('开始建立连接...');
while (true) {
sleep(120);
dump($TicketModel->select('t_id')->fetch());
}
}
发现在100s后的连接已被主动断开
代码中的场景是，在wait_timeout之内无任何操作会自动关闭
官方解释
interactive_timeout 28800
The number of seconds the server waits for activity on an interactive connection before closing it. An interactive client is defined as a client that uses the CLIENT_INTERACTIVE option to mysql_real_connect(). See also wait_timeout.
waitimeout 28800
The number of seconds the server waits for activity on a noninteractive connection before closing it.
On thread startup, the session wait_timeout value is initialized from the global wait_timeout value or from the global interactive_timeout value, depending on the type of client (as defined by the CLIENT_INTERACTIVE connect option to mysql_real_connect()). See also interactive_timeout.
通过MySQL客户端连接db的是交互会话，通过jdbc等程序连接db的是非交互会话。
总结：
如果应用程序长时间的使用一个连接，而有机会长时间不进行任何操作。则会导致连接被关闭。
参考文献:
1.https://dev.mysql.com/doc/refman/5.7/en/server-system-variables.html
2.https://cloud.tencent.com/developer/article/1181515
