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DB gets 100% of cpu time

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Christian Marquardt_1
Regular Advisor

DB gets 100% of cpu time

Hi guys,
I've a terrible problem. We run a single instance db on an rp4440 with HP/UX 11.11 64-Bit.
If we start this instance it will consume all the cpu time.
We've an RAC db installed on this machine but it's the same problem with the RAC instance started or not.
Does anyone has an idea where to start analyze this "feature"???

regards
Christian
8 REPLIES
Christian Marquardt_1
Regular Advisor

Re: DB gets 100% of cpu time

PS: the db is a 9.2.0.8.0 and the datafile are in cooked filesystem (veritas).
Yogeeraj_1
Honored Contributor
Solution

Re: DB gets 100% of cpu time

hi,

How much time do this situation persist?

There could be scheduled jobs that starts to run as soon as the database is up.

(to check: select * from dba_jobs_running;)

Does the alert.lgo show any error messages?

revert
kind regards
yogeeraj

No person was ever honoured for what he received. Honour has been the reward for what he gave (clavin coolidge)
Christian Marquardt_1
Regular Advisor

Re: DB gets 100% of cpu time

Hi Yogeeraj,
yes we've tried the to set job_queue_processes to 0 and it doesnt change everything.
The issue occurs all the time and the alert.log shows nothing?!?!?!?!?
Thats my problem I dont know where to look ...

regards
Christian
Jonathan Fife
Honored Contributor

Re: DB gets 100% of cpu time

Does it happen if you startup with the listener shut down?
Does anything odd show up in the top SQL report?
Does it happen if you don't open the DB upon startup?
Decay is inherent in all compounded things. Strive on with diligence
Todd McDaniel_1
Honored Contributor

Re: DB gets 100% of cpu time

Christian,

How long does it take to max out your cpu util?

I would suggest that you monitor the cpu and run a cpu report over the time frame that begins when you start the instance and track the cpu util.

If you haven't already looked, I would check with Oracle about this behavior and see if there isnt a patch or a configuration setting that you are missing.
Unix, the other white meat.
Yogeeraj_1
Honored Contributor

Re: DB gets 100% of cpu time

hi again,

Has there been any changes prior to this behaviour? Changes at the SGA level?

Can you post a sample output from TOP? Did you try to relate the top processes with database sessions at the instance level?

revert
kind regards
yogeeraj
No person was ever honoured for what he received. Honour has been the reward for what he gave (clavin coolidge)
kenj_2
Advisor

Re: DB gets 100% of cpu time

Christian -

What are the names of the processes that are using the cpu cycles ? Glance is the best tool for finding this out. If you don't have Glance, you can use top or repeated ps commands - looking at changes in cpu consumption.

Is any Oracle work getting done when this occurs ?

Ken Johnson
Christian Marquardt_1
Regular Advisor

Re: DB gets 100% of cpu time

Hi Guys,
there was a HP/UX patch installed on the one machine and after that this error occurs. Right now the unix-admins have restored the hole machine to an prior patch backup and everything works fine. But I cannot analyze this "feature" anymore.
Thanks for your help!

regards
Christian