RE: waits vs. logons

[Cary Millsap]

Title: Message

First, you’re missing user-mode CPU time consumed by the Oracle session. The statistic that is supposed to hold this number is ‘CPU used by this session’ from v$sesstat. But there are bugs in that statistic. Second, some of the time that an Oracle process spends sleeping (because of context switches imposed by a timesharing operating system) isn’t counted either. See www.hotsos.com/dnloads/1/kevents/unaccounted-for.html for a start. Our Hotsos Clinic explains in complete detail.   Cary Millsap Hotsos Enterprises, Ltd. http://www.hotsos.com Upcoming events: - Hotsos Clinic, Oct 1–3 San Francisco, Oct 15–17 Dallas, Dec 9–11 Honolulu - 2003 Hotsos Symposium on Oracle® System Performance, Feb 9–12 Dallas - Next event: Miracle Database Forum, Sep 20–22 Middlefart Denmark -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Terrian, Tom Sent: Wednesday, September 04, 2002 4:00 PM To: Multiple recipients of list ORACLE-L Subject: waits vs. logons   I run the following query to compare the total waits for a session verses the seconds logged on:   select a.sid, a.ontime longon_secs, round(b.waittime) wait_secs from   (select sid, (sysdate - logon_time)*24*60*60  ontime    from   v$session ) a,   (select sid, sum(time_waited)/100 waittime    from v$session_event    group by sid) b where a.sid = b.sid; I get the following results:          SID LONGON_SECS  WAIT_SECS ---------- ----------- ----------          1      595995     595989          2      595994     471204          3      595994     595585          4      595994     594580          5      595994     595492          6      595994     593639          9      595993     577157         14        4943       1303         24      595844     588441         26        1733       1728         27        5308       2478         29      517269          0         32          53          0         35      415158         13         50      140478     140371         51         719        507         56       14507       8706         59        2269        221   I am very much a novice when it comes to wait statistics.  When a session, for example #51, has been logged on for 719 seconds but has experienced only 507 wait seconds, what did it do the rest of the time?  I am assuming some kind of work?  Any way to determine what?   Tom