Whether or not the event SQL*Net message from client (and SQL*Net message from dblink) should be ignored depends on how the application works. Foreground processes post this event when they wait for instructions from client processes. In other words, the foreground processes are sitting idle waiting for more work to do. For example, a user may run a short query and spend time looking at the result or go out to lunch without logging off. All the while, the foreground process faithfully waits for the user to return, posting the SQL*Net message from client event and increasing the value in the TIME_WAITED column. Therefore, the SQL*Net message from client is the most preva lent event in OLTP systems, and this is why many DBAs choose to ignore this event.
列举几个常用的 none idle 事件，对比上面的idle events。（思考一下 sql net message from client 和more from client的区别），
