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RE: Increasing CPU on every execution of an anonymous block sent from WebLogic

From: Mark W. Farnham <mwf_at_rsiz.com>
Date: Wed, 21 Mar 2007 11:00:26 -0400
Message-ID: <01d001c76bc9$aa1f3940$1100a8c0@rsiz.com>


okay, I'll bite -- What else is going on in this block?

Are queries, potentially involving blocks and indexes affected by the inserts being iteratively queried between the inserts?

Since the bind variables are constant in name, this implies they must be set to new values either by query or new value assignment in the pl/sql code. The former could be affected by what our friend Tom Kyte refers to as write consistency, while the latter would still imply a full stack line turn around to the client (that is where your pl/sql is running, right?).

Sounds to me like either possibility is the wrong way to run a railroad, even if some bug can be discovered and fixed to make the performance within your service level requirements.

Regards,

mwf

-----Original Message-----
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Baumgartel, Paul
Sent: Wednesday, March 21, 2007 9:44 AM
To: 'Alberto Dell'Era'; Baumgartel, Paul Cc: oracle-l_at_freelists.org
Subject: RE: Increasing CPU on every execution of an anonymous block sent from WebLogic

The timings are for serial execution of the block by the same connection.

The text of the block, including bind names, is identical every time.

Paul Baumgartel
CREDIT SUISSE
Information Technology
DBA & Admin - NY, KIGA 1
One Madison Avenue
New York, NY 10010
USA
Phone 212.538.1143
paul.baumgartel_at_credit-suisse.com
www.credit-suisse.com

-----Original Message-----
From: Alberto Dell'Era [mailto:alberto.dellera_at_gmail.com] Sent: Tuesday, March 20, 2007 3:52 PM
To: paul.baumgartel_at_credit-suisse.com
Cc: oracle-l_at_freelists.org
Subject: Re: Increasing CPU on every execution of an anonymous block sent from WebLogic

  > Analysis of the trace files for the bind-variable version reveals that the
> CPU time to EXEC the anonymous block (and, to a lesser extent, its
> constituent INSERT statements) steadily increases. The first time
> through the CPU time is about 0.02 second. By the last execution
> before the timeout, the CPU time is just about 1.0 second.
> Interestingly, the logical I/O stats for each execution are quite low
> (<100 current reads and consistent reads) and quite consistent.

Are those timings for a serial execution of the block by the same connection, or by concurrent execution by different connections ?

Is the block identical for bind variables names also ? ie

begin
  insert ... values (:bind_one);
  insert ... values (:bind_one);
end;

or

begin
  insert ... values (:bind_one);
  insert ... values (:bind_TWO);
end;

--
Alberto Dell'Era
"dulce bellum inexpertis"

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Received on Wed Mar 21 2007 - 10:00:26 CDT

Original text of this message

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