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disk read speed [message #299350] Mon, 11 February 2008 10:43 Go to next message
Messages: 4
Registered: September 2006
Location: Belgium
Junior Member
I need to improve request time.
In order to preload oracle blocks into memory I do "SELECT" from some table.
The problem is that ORACLE doesn't charge the disk up to his limits.
For example, the disk read spead during the simple "dd" unix command shows 60 MB/sec and during the query ORACLE loads only at 45 MB/sec (with an "ALTER SESSION FORCE PARALLEL QUERY;")

Is there any method to set up the speed at maximum?
Re: disk read speed [message #299351 is a reply to message #299350] Mon, 11 February 2008 10:47 Go to previous message
Michel Cadot
Messages: 65079
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
Oracle also has to maintain its internal structure when it loads blocks in buffer cache.
So you can never have the same performances than with "dd of=/dev/null" that just read the blocks but does no work.
I think with 75%, Oracle is pretty good.

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