Re: Can I tryst in "physical ... direct" figures?

  • From: zhu chao <zhuchao@xxxxxxxxx>
  • To: "j.velikanovs@xxxxxxxx" <j.velikanovs@xxxxxxxx>
  • Date: Fri, 24 Sep 2004 22:02:50 +0800

Cound you use the following SQL to find out which session does most of
the write?

As you mentioned you run ad-hoc query and it is like a datawarehouse,
so physical reads direct can be explained via the parallel slave
process doing the direct path read,

and possibly the direct path write can be done via the sqlldr direct
path write? and create table as select?


maybe you can use sql like the following one to find out which session
does most of the direct path write(if the session hasn't logout, or
you are using middleware).
set line 200
select  b.sid,a.name,b.value from v$sesstat b, v$statname a
where a.statistic#=b.statistic#
and (a.name like '%physical writes direct%' or a.name like 'physical writes')
and b.value>0
order by b.value asc
/



----- Original Message -----
From: j.velikanovs@xxxxxxxx <j.velikanovs@xxxxxxxx>
Date: Fri, 24 Sep 2004 16:14:53 +0300
Subject: Re: Can I tryst in "physical ... direct" figures?
To: zhu chao <zhuchao@xxxxxxxxx>


Hi Zhu, 

Thanks for respnce. 
With reads it can be as you described. 
At the mopment I thought more about writes. 
How Direct writes cant be 98% of all writes if there olmost no sorts
in the system, i wonder?

Jurijs
+371 9268222 (+2 GMT)
============================================
Thank you for teaching me.
http://otn.oracle.com/ocm/jvelikanovs.html





zhu chao <zhuchao@xxxxxxxxx> 

24.09.2004 15:36 
Please respond to zhu chao         
        To:        j.velikanovs@xxxxxxxx 
        cc:         
        Subject:        Re: Can I tryst in "physical ... direct" figures?






Hi ,
  Since disk sort is very few times, maybe it is "parallel server
direct path read", since there isn't parallel_max_servers specified in
your spfile, the default value is 4.
 So, it is possible you are using parallel slave server to do direct path read.



-- 
Regards
Zhu Chao
www.cnoug.org





-- 
Regards
Zhu Chao
www.cnoug.org
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