Home » RDBMS Server » Performance Tuning » High CPU Utilization in RAC and Log file sequential Read Event (Oracle, 10.2.0.4.0, AIX .3)
High CPU Utilization in RAC and Log file sequential Read Event [message #503252] Wed, 13 April 2011 15:31 Go to next message
pchandna1
Messages: 24
Registered: March 2011
Location: USA
Junior Member

Hi Group,

I have situation here to discuss. In a 3-node RAC setup; one node is showing high CPU utilization around 40~50%. The CPU utilization was less than 20% 10 days back but from 9th oldest day it jumped and consistently shows the double figure. I ran AWR reports on all three nodes and found one node with high CPU utilization and shows below tops events-

EVENT WAITS TIME(S) AVG WAIT(MS) %TOTAL CALL TIME WAIT CLASS
CPU
time 5,802 34.9

RFS
ping 15 5,118 33,671 30.8 Other

Log file sequential
read 234,831 5,036 21 30.3 System I/O

Sql*Net
more data from
client 24,171 1,087 45 6.5 Network

Db file sequential
read 130,939 453 3 2.7 User I/O

Findings:-
On AWR report(file attached) for node= sipd207; we can see that "RFS PING" wait event takes 30% of the waits and "log file sequential read" wait event takes 30% of the waits that occurs in database.

1)Are these symptoms of undersized log buffer?
2)I feel Network wait can be reduced by tweaking SDU & TDU values based on MDU.
3)Can somebody put light on RFS Ping event and any direction to some documentation will great help.

Apologies unable to upload AWR reports due to size constraints 2048KB.

Thanks in advance for your guidenace and comments
  • Attachment: SIPD207.jpg
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Re: High CPU Utilization in RAC and Log file sequential Read Event [message #503277 is a reply to message #503252] Thu, 14 April 2011 02:20 Go to previous messageGo to next message
John Watson
Messages: 8922
Registered: January 2010
Location: Global Village
Senior Member
Can you upload the AWR reports if you generate them as txt files, not as html?
Re: High CPU Utilization in RAC and Log file sequential Read Event [message #503648 is a reply to message #503277] Mon, 18 April 2011 13:58 Go to previous message
pchandna1
Messages: 24
Registered: March 2011
Location: USA
Junior Member

Apologies; lost in other work.
I'm attaching '.txt' files for refernece. FYI - this a logical stanby DB.

Regards
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