那是不是我们每当遇到性能问题的时候都要patch到9.2.0.3呢？
我们已经知道他的真实情况依然在v$session_wait的p1、p2、p3参数里体现，所以，我们可以根据这些参数，找出这个null event究竟是什么等待事件。
相关信息：
1. lck processes to pick up extra or missed 'posts' (messages)。
in all cases that can be identified the wait time is zero，
although on most ports this is changed to 1/100th second in
order to force the process to be rescheduled.
2. multiple db writers.
two cases：
- when the master has sent i/o requests to the slaves， it
waits on this event for up to 6 seconds until the slaves
signal that the i/o is complete.
- the slaves wait on this event for up to 3 seconds whilst
waiting for requests from the master db writer.
目前已经被证实的会涉及到null event
的等待事件还有有sql.net message to client、
db file scattered (or sequential) read
MSN:
posted on 2008-02-15 01:03 kylixlu 阅读(140) 评论(0) 编辑 收藏 所属分类: Database
