kettle作业在运行一段时间后会报错，原因是mysql会默认每8小时回收一次无用连接。错误日志如下：

记录保存到数据库中.0 – The last packet successfully received from the server was 612,479,928 milliseconds ago. The last packet sent successfully to the server was 612,479,928 milliseconds ago. is longer than the server configured value of ‘wait_timeout’. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property ‘autoReconnect=true’ to avoid this problem.

然后你的作业就失败了，必须重新启动kettle才能解决。
经过多次排查，最终解决。

无效解决方案:

加上 autoReconnect=true 参数

外部解决方案:

虽然能解决8小时mysql自动丢弃无用连接的问题，但是不能解决mysql宕机后的自动重连。