Home » RDBMS Server » Server Administration » How Can I calculate the DBIO_EXPECTED? (Oracle 10gR2)
How Can I calculate the DBIO_EXPECTED? [message #333642] Mon, 14 July 2008 00:39 Go to next message
mafc73
Messages: 38
Registered: November 2006
Member
I know that this is an important parameter for ADDM, but I don't know how can I calculate it.

Thanks.
Re: How Can I calculate the DBIO_EXPECTED? [message #333705 is a reply to message #333642] Mon, 14 July 2008 03:43 Go to previous messageGo to next message
alanm
Messages: 282
Registered: March 2005
Senior Member

hi,

To determine the correct setting for the DBIO_EXPECTED parameter:

Measure the average read time of a single database block for your hardware.

This measurement needs to be taken for random I/O, which includes seek time if you use standard hard drives. Typical values for hard drives are between 5000 and 20000 microseconds.

Set the value one time for all subsequent ADDM executions.

For example, if the measured value if 8000 microseconds, run the following command as SYS user:

EXECUTE DBMS_ADVISOR.SET_DEFAULT_TASK_PARAMETER(
'ADDM', 'DBIO_EXPECTED', 8000);

this is from a google search.

cheers

Alan

[Updated on: Thu, 17 July 2008 11:14] by Moderator

Report message to a moderator

Re: How Can I calculate the DBIO_EXPECTED? [message #333709 is a reply to message #333705] Mon, 14 July 2008 03:59 Go to previous messageGo to next message
mafc73
Messages: 38
Registered: November 2006
Member
I know how to set SET_DEFAULT_TASK_PARAMETER but I want to know how can I measure the read time of a single block. In a oracle view? where can I see it?. If not, what is the procedure to obtain it?

Thanks
Re: How Can I calculate the DBIO_EXPECTED? [message #333726 is a reply to message #333709] Mon, 14 July 2008 04:58 Go to previous message
Michel Cadot
Messages: 64139
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
DBMS_STATS.GATHER_SYSTEM_STATS
sys.aux_stats$
v$filestat
...

Regards
Michel
Previous Topic: Audit files
Next Topic: ORA-01078: failure in processing system parameters
Goto Forum:
  


Current Time: Thu Dec 08 20:20:36 CST 2016

Total time taken to generate the page: 0.14792 seconds