Not sure if this has been mentioned some where, but it used to be that UNIX would lower priority of processes that had accumulated a lot of CPU time. So the Oracle Background processes would get lower priority over time. Stopping and starting an instance will fix this again ;-)
Cary Millsap wrote: >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 >[EMAIL PROTECTED] >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? > >************************************************************************ >**** >* >WARNING: do not run Oracle processes at different priority by altering >the nice value. This is specifically warned against in the manuals. >If you have a process with a lowered priority that obtains a lock on >an object, then can't run because of the low priority, you will create >a deadlock or hang situation. All Oracle processes should run at the >same priority. > > -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Anjo Kolk INET: [EMAIL PROTECTED] 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: [EMAIL PROTECTED] (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).