在MySQL，Grails 2应用程序更长时间不活动期间保持池连接的正确方法（或将它们计时并获得新的连接）的正确方法

I have a grails app that has flurries of high activity, but then often periods of inactivity that can last several hours to over night. I notice that the first users in the morning get the following type of exception, and I believe this is due to the connections in the pool going stale and MYSql database closing them. I have a grails app that has flurries of high a