null event不是空事件
那是不是我們每當遇到性能問題的時候都要patch到
我們已經知道他的真實情況依然在v$session_wait的P
下面是ITPUB上COPY過來的一些信息
In all cases that can be identified the wait time is zero
although on most ports this is changed to
order to force the process to be rescheduled
Two cases:
waits on this event for up to
signal that the i/o is complete
waiting for requests from the master db writer
目前已經被證實的會涉及到null event 的等待事件還有有SQL*Net message to client
From:http://tw.wingwit.com/Article/program/Oracle/201311/17565.html