RE: Direct I/O, better performance?

From: "Gogala, Mladen" <Mladen.Gogala@xxxxxxxx>
To: "'roger_xu@xxxxxxxxxxx'" <roger_xu@xxxxxxxxxxx>, "Oracle-L@Freelists. Org (E-mail)" <oracle-l@xxxxxxxxxxxxx>
Date: Tue, 19 Oct 2004 15:37:00 -0400

a) What did you want to achieve by switching to direct I/O?
b) Do you know what is direct I/O and what are the benefits?
c) Are you talking about DBMS_STATS? 
d) Why would you expect DBMS_STATS to run faster with the direct I/O?
   I'd expect it to run slower, because of the the prefetch which is
   gone with the direct I/O.


--
Mladen Gogala
A & E TV Network
Ext. 1216


> -----Original Message-----
> From: Roger Xu [mailto:roger_xu@xxxxxxxxxxx] 
> Sent: Tuesday, October 19, 2004 3:16 PM
> To: Oracle-L@Freelists. Org (E-mail)
> Subject: Direct I/O, better performance?
> 
> 
> Hi,
>  
> We are running Solaris 9 with UFS on Oracle 9.2.0.4.0.
> We switched to direct I/O and did not see a better 
> performance as far as updating statistics concerned. Why?
>  
> It used to take us 22 hours to update statistics for all 
> tables, but now 31 hours.
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//www.freelists.org/webpage/oracle-l

RE: Direct I/O, better performance?

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