RE: High CPU on Host
Date: Wed, 29 Sep 2021 15:54:04 +0000
Message-ID: <CO1PR19MB4984CF007212390ADC84CAC69BA99_at_CO1PR19MB4984.namprd19.prod.outlook.com>
First things I’d look for would be someone fiddling with resource manager (CPU limits) and/or the number of CPUs actually “turned on” in the Exadata.
Clay Jackson
From: oracle-l-bounce_at_freelists.org <oracle-l-bounce_at_freelists.org> On Behalf Of Pap
Sent: Wednesday, September 29, 2021 8:13 AM
To: Lok P <loknath.73_at_gmail.com>
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I checked that it has been increased for all schemas/users. Even i see the "insert into table... values() " type of queries which were loading data in batches are having an increase in run duration(~10times) and its mainly CPU time observed. What must be the reason?
On Wed, Sep 29, 2021 at 7:26 PM Lok P <loknath.73_at_gmail.com<mailto:loknath.73_at_gmail.com>> wrote:
From dba_hist_sqlstat you can fetch the sum(cpu_time_delta) order by parsing_schema_name to see if any specific user is standing out with respect to the overall cpu time consumption for good day vs bad day. If it's equally increased for all the users then mostly the issue is outside the database or perhaps need to see host related things then.
On Wed, Sep 29, 2021 at 6:39 PM Pap <oracle.developer35_at_gmail.com<mailto:oracle.developer35_at_gmail.com>> wrote:
Hello Listers, This is an exadata(X3 full rack) machine. One of the hosts/compute nodes hosting two database nodes with version 19.9.0.0.0 and 11.2.0.4 respectively. We are encountering a situation in which suddenly the query execution time has been increased by almost ~50% for many queries in this database without any change in plan and change in data volume. Checking the host cpu utilization trend, it's almost doubled from around that exact time when queries ran longer. The waits for those queries are all DB CPU. Not sure what the cause and what is the effect here. If something wrong on the host/hardware is impacting queries or something wrong with the database/queries itself(but then it looks odd that many queries are running longer which were running fine since the past).
We checked with the infra team regarding any change that went in for that host but got an answer as NO. And we didn't see any new queries/functionalities introduced which might cause this sudden spike in CPU. So I wanted to understand from experts, how can we get to the bottom of this issue in such a situation?
Cc: Oracle L <oracle-l_at_freelists.org>
Subject: Re: High CPU on Host
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Received on Wed Sep 29 2021 - 17:54:04 CEST