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Home -> Community -> Mailing Lists -> Oracle-L -> RE: UNIX nice Command Good/Bad
Anything that an OS does to raise or lower process priority without the
Oracle kernel's knowing is a bad thing.
Example: An inefficient process called L that makes way too many cache buffer chains acquisitions is demoted ("nice"d to a less important priority). An important job called H that needs some of the same latches is promoted ("nice"d to a more important priority). L, which gets some user-mode CPU time in spite of its poor priority, works long enough to acquire a latch, and then it gets preempted. Now, when H needs the same latch that L is holding, H will consume lots of CPU spinning for the latch, but of course H can never obtain the latch until L releases it. But L is asleep most of the time because it has a low priority. You'll have a busy-looking system (high CPU utilization because of H's spinning), but nobody will be able to get anything done.
When the Oracle kernel provides process prioritization or suspend/resume capabilities, it'll be fantastic (I think they advertise some of this stuff in 9i, but I'm not sure it works yet). But no OS can do the job unless it takes into account some of the things that Oracle is doing internally.
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 OracleR System Performance, Feb 9-12 Dallas
- Next event: NCOAUG Training Day, Aug 16 Chicago
-----Original Message-----
Ethan
Sent: Tuesday, August 06, 2002 5:23 PM
To: Multiple recipients of list ORACLE-L
There is an article on Metalink that talks about doing this and doesn't
mention the problem but I will take your word over that. Another post
on
usenet talked about some different software available on particular
operating systems that would do the smae thing as "nice" but I guess it
does
is a little more "nicley". Would this be safe? How about punishing the
whole lot and forcing all processes with a particular database to run at
a
lower level?
Ethan Post
(972) 577-6552
Ethan.Post_at_ps.net
perotdba (AIM), epost1 (Yahoo)
-----Original Message-----
Sent: Tuesday, August 06, 2002 4:28 PM
To: Multiple recipients of list ORACLE-L
Still true.
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 OracleR System Performance, Feb 9-12 Dallas
- Next event: NCOAUG Training Day, Aug 16 Chicago
-----Original Message-----
Ethan
Sent: Tuesday, August 06, 2002 3:58 PM
To: Multiple recipients of list ORACLE-L
Is this still true?
--
--- Allen Kirby AT&T ITS Production Services akirby_at_att.com Alpharetta, GA. ************************************************************************ **** * Ethan Post perotdba (AIM), epost1 (Yahoo) --------------------------------------------------------------------Received on Tue Aug 06 2002 - 20:03:35 CDT
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Author: Post, Ethan INET: Ethan.Post_at_ps.net Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
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Author: Cary Millsap INET: cary.millsap_at_hotsos.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
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Please see the official ORACLE-L FAQ: http://www.orafaq.com
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Author: Post, Ethan INET: Ethan.Post_at_ps.net Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
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Author: Cary Millsap INET: cary.millsap_at_hotsos.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
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