等待事件（）

1. rdbms ipc message timeout:

the background processes (LGWR, DBWR, LMS0) use this event to indicate that they are idle and are waiting for the foreground processes to send them an IPC message to do some work.

Wait Time: Up to 3 seconds. The parameter timeout shows the true sleep time.

2.SQL*Net message from client

server process 空闲，在等待clinet process的连接。如果网络没有问题，说明服务器太闲啦。