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rdbms 12.2C performance issues sometimes [message #687685]

Fri, 05 May 2023 10:49

evoradba
Messages: 144
Registered: April 2005
Location: Canada

Senior Member

hello all
we have a database 12c LINUX RAC on ODA, using the same job and same data over and over the performance varies from 30 seconds to hours, i have looked a the plan and is the same but points to CPU which is high, I have a ticket open with Oracle they are telling me is the CPU which is slow, but why would work sometimes the host same data same everything.

Has anyone seen any issues with ODA performance?

Time & Wait
Duration
6.98 h
Database Time
6.98 h
PL/SQL & Java
0 s
Wait Activity
100%
I/O
Buffer Gets
9,170 M
I/O Requests
3,328
I/O Byt

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Re: rdbms 12.2C performance issues sometimes [message #687686 is a reply to message #687685]

Fri, 05 May 2023 12:16

John Watson
Messages: 8976
Registered: January 2010
Location: Global Village

Senior Member

You would need to look at the wait events, they should explain what is happening. If you have the AWR licence (most ODA environments do) generate reports that cover the fast and the slow runs and then SQL reports for the problem statements.

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Re: rdbms 12.2C performance issues sometimes [message #687687 is a reply to message #687686]

Fri, 05 May 2023 12:20

evoradba
Messages: 144
Registered: April 2005
Location: Canada

Senior Member

thank you, yes i have done that already, oracle says is CPU but if is CPU why would the job run sometimes good others not?
I found this, however we have a higher version of ODA and db
Alert - ODA: Extreme Slow IO Performance including: Possible Hang, Poor Disk or Diskgroup Performance with Low IO but High CPU Utilitization (Doc ID 2189437.1)

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Re: rdbms 12.2C performance issues sometimes [message #687688 is a reply to message #687687]

Fri, 05 May 2023 12:26

John Watson
Messages: 8976
Registered: January 2010
Location: Global Village

Senior Member

If you post the reports here, perhaps someone can advise. For example, if it really is the same plan and the same data, then the answer would likely be run time variables: all the things that happen after the parse. Eg, the choice between serial and direct read; the adaptive features; and, of course, all the wait events that are related to runtime variables. The reports will make this clear.

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Re: rdbms 12.2C performance issues sometimes [message #687697 is a reply to message #687688]

Thu, 11 May 2023 08:58

evoradba
Messages: 144
Registered: April 2005
Location: Canada

Senior Member

thank you , found the problem its a disk problem

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