Re: Query processing takes very variable time

Reminds me of an episode of House... Patient comes in with a wide collection of 
odd symptoms... patient is unconscious so they can't get any real medical 
history... the result is a massive throwing out of ideas and eliminating them 
one by one based on the symptoms. Differential diagnosis.... Actually kind of 
fun in the database world if you are not under the gun to fix something. :-)



RF


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________________________________
From: David Barbour <david.barbour1@xxxxxxxxx>
To: oracledba.williams@xxxxxxxxx
Cc: Pradeep.Chetal@xxxxxxxxxxxxxx; Jared Still <jkstill@xxxxxxxxx>; 
oracle-l@xxxxxxxxxxxxx
Sent: Tuesday, December 30, 2008 10:56:25 AM
Subject: Re: Query processing takes very variable time

It might help if we knew the version of Oracle and the Operating System at a 
minimum.  Since we're tossing about WAGS, why not check to make sure the 
optimizer settings on both instances are identical?


On Tue, Dec 30, 2008 at 11:06 AM, Dennis Williams 
<oracledba.williams@xxxxxxxxx> wrote:

Pradeep,
 
As others have pointed out, there can be many reasons for erratic behavior. 
 
Here is my personal favorite. If you are using bind variables, the first time 
the statement is parsed, an execution plan is created, and all subsequent 
executions use that plan. So, suppose after the database is bounced, the first 
execution has bind variables that causes an unusual execution plan. All future 
executions will get that plan. Nice.
 Dennis Williams


On Mon, Dec 29, 2008 at 6:53 PM, Pradeep Chetal <Pradeep.Chetal@xxxxxxxxxxxxxx> 
wrote:

 
Sorry, Jared for the cryptic request. It is a complex process to set up the 
tables, etc, but once they are set, we run a stored proc that works on these 
tables - and the SQL code seems very simple - selects, inserts, and updates 
[even those are simple, nothing fancy ]. However, the processing factor takes 
long sometimes (not all the times).
 
I was hoping to look for *extraneous* factors (outside the code) that can 
affect the processing and if anyone on this list has any experience like that.
 
Thanks,
 
-- Pradeep
 

________________________________
 
From:Jared Still [mailto:jkstill@xxxxxxxxx] 
Sent: Monday, December 29, 2008 3:17 PM
To: Pradeep Chetal
Cc: oracle-l@xxxxxxxxxxxxx
Subject: Re: Query processing takes very variable time
 
 
On Mon, Dec 29, 2008 at 5:46 AM, Pradeep Chetal <Pradeep.Chetal@xxxxxxxxxxxxxx> 
wrote:
Without going into complete details, has anyone on the list seen something like 
that? Any ideas. 
Without going into complete explanations, yes.


Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist

  
 
 
Pradeep Chetal
Sr. Director - Infrastructure Architecture

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