Re: Query processing takes very variable time
- From: Robert Freeman <robertgfreeman@xxxxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Tue, 30 Dec 2008 10:02:36 -0800 (PST)
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
Robert G. Freeman
Author:
OCP: Oracle Database 11g Administrator Certified Professional Study Guide
(Sybex)
Oracle Database 11g New Features (Oracle Press)
Portable DBA: Oracle (Oracle Press)
Oracle Database 10g New Features (Oracle Press)
Oracle9i RMAN Backup and Recovery (Oracle Press)
Oracle9i New Features (Oracle Press)
Other various titles out of print now...
Blog: http://robertgfreeman.blogspot.com
The LDS Church is looking for DBA's. You do have to be a Church member in
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the law by saying you have to be a Church member. It's legal I promise! :-)
________________________________
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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