RE: INSERT...SELECT pegs CPU, but is waiting on scattered read?

From: "Cary Millsap" <cary.millsap@xxxxxxxxxx>
To: <oracle-l@xxxxxxxxxxxxx>
Date: Thu, 29 Apr 2004 21:10:12 -0500

Your shared memory configuration is probably irrelevant to your problem
at hand. Your problem is the number of memory accesses your application
SQL is demanding, not the duration of each access...


Cary Millsap
Hotsos Enterprises, Ltd.
http://www.hotsos.com
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-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Jesse, Rich
Sent: Thursday, April 29, 2004 3:13 PM
To: 'oracle-l@xxxxxxxxxxxxx'
Subject: RE: INSERT...SELECT pegs CPU, but is waiting on scattered read?

Or, I could just look at the swaping and paging from gpm...  :)  Nothing
out
of the ordinary shows there (mostly process activation from 4GLs), but I
notice in "ipcs -ma" that the SGA is broken into 9 chunks.  I'm guessing
SHMMAX is too low.  But that wouldn't cause a proc to spin in CPU would
it?

Rich Jesse                        System/Database Administrator
rich.jesse@xxxxxxxxxxxxxxxxx      QuadTech, Sussex, WI USA


> -----Original Message-----
> From: Mladen Gogala [mailto:mladen@xxxxxxxxxxxxxxx]
> Sent: Thursday, April 29, 2004 2:41 PM
> To: oracle-l@xxxxxxxxxxxxx
> Subject: Re: INSERT...SELECT pegs CPU, but is waiting on 
> scattered read?
> 
> 
> 
> On 04/29/2004 03:08:59 PM, Cary Millsap wrote:
> > If you can still connect to Oracle, you'll probably see a tremendous
> > amount of activity reflected in V$SESS_IO.BLOCK_GETS and
> > ~.CONSISTENT_GETS. Cut the SELECT statement into a SQL*Plus 
> session and
> > go to work on "tuning the SQL." This (a SQL tuning issue) is almost
> > undoubtedly the cause of your problem.
> 
> But he has the perfect BCHR now! This is the illustration for 
> your "method R".
> He has the perfect BCHR and he's an unhappy camper, to say 
> the least. I have one
> more question: is CPU being spent in system or user mode? If 
> the CPU is
> spent in the system mode and you don't  have logical I/O, 
> then may be you
> are paging (a.k.a "thrashing").
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References:
- RE: INSERT...SELECT pegs CPU, but is waiting on scattered read?
  - From: Jesse, Rich

RE: INSERT...SELECT pegs CPU, but is waiting on scattered read?

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