在帖子“1次cursor: pin S wait on X事件的跟踪 ”(http://blog.csdn.net/msdnchina/article/details/45372011)中,有1个知识点,原作者没有写出计算进程:
SQL> select distinct session_id,session_serial#,p1,p2
2 from temp_hist_active_sess_history
3 where event ='cursor: pin S wait on X'
4 and rownum<=50;
的查询结果中,我们来分析p2=21333102559232,前两个字节数据为 4967
注:temp_hist_active_sess_history的建表语句为:
SQL> create table temp_hist_active_sess_history nologging as
2 select * from dba_hist_active_sess_history
3 where to_char(sample_time, 'yyyymmddhh24') between '2011030717' and '2011030722';
我们来分析p2=21333102559232(p2为10进制),前两个字节数据为 4967 --的计算进程以下:
--转换为16进制
select to_char(21333102559232,'xxxxxxxxxxxxxxxxxxxxxxxxxxxx') from dual;
------返回136700000000,高位补全4个0:
也就是0000136700000000
取高位8bytes:00001367
select to_number('00001367','xxxxxxxxxxxxxxxxxxxxxxxxxxxxx') from dual;
------返回4967
另外的1个知识点:
dba_hist_active_sess_history 视图中:
没有p1raw列(为16进制),只有p1列,p1列 number型,为10进制,
没有p2raw列(为16进制),只有p2列,p2列 number型,为10进制;
没有p3raw列(为16进制),只有p3列,p3列 number型,为10进制;
v$session 和 v$session_wait 视图中:
有p1raw列(为16进制),有p1列,p1列 number型,为10进制,
有p2raw列(为16进制),有p2列,p2列 number型,为10进制;
有p3raw列(为16进制),有p3列,p3列 number型,为10进制