RE: 10g slowdown

From: Johnson, William L (TEIS) <WLJohnson_at_tycoelectronics.com>
Date: Fri, 12 Dec 2008 14:41:06 -0500
Message-ID: <2F161F8A09B99B4ABF8AE832D546E789020B5AB0BA@us194mx002.tycoelectronics.net>


Check out this article - it has some good information to help explain what you are seeing...

www.oracle.com/technology/oramag/oracle/08-jan/o18asktom.html

-----Original Message-----

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Blanchard William Sent: Friday, December 12, 2008 2:18 PM
To: mfontana_at_enkitec.com; oracle-l_at_freelists.org Subject: RE: 10g slowdown

We looked at the program in SAP and the table & indexes in Oracle and nothing directly related to the query has changed. Is there anything that would cause Oracle to not use the right index in SAP but works fine when run in sqlplus?

William

-----Original Message-----

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Michael Fontana Sent: Friday, December 12, 2008 1:15 PM
To: mfontana_at_enkitec.com; oracle-l_at_freelists.org Subject: RE: 10g slowdown

I would try executing the statement with sqlplus independent of SAP if possible. Sorry in advance if you've already done so....

-----Original Message-----

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org]
On Behalf Of Michael Fontana
Sent: Friday, December 12, 2008 1:12 PM
To: oracle-l_at_freelists.org
Subject: RE: 10g slowdown

This is a good point - because of a logic error - or programming bug - depending upon how you look at it - we had an innocent single-row query which was in a called program that was executed millions of times.

This is not an uncommon situation with SAP, depending upon some configuration settings.

-----Original Message-----

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org]
On Behalf Of Johnson, William L (TEIS)
Sent: Friday, December 12, 2008 12:57 PM To: somckit.khemmanivanh_at_weyerhaeuser.com; 'William.Blanchard_at_kohler.com'; Allen, Brandon Cc: oracle-l_at_freelists.org
Subject: RE: 10g slowdown

Are you sure that this statement is not being executed multiple times? We have run into sql statements that look pretty simple - until a program executes them multiple times...

-----Original Message-----

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org]
On Behalf Of Khemmanivanh, Somckit
Sent: Friday, December 12, 2008 1:31 PM
To: 'William.Blanchard_at_kohler.com'; Allen, Brandon Cc: oracle-l_at_freelists.org
Subject: RE: 10g slowdown

Just a thought...

Can you reproduce the issue in a QA system?

Is your QA system periodically refreshed?

Another idea would be to run a quick check of your Oracle Parameters against the SAP recommended values...

SAP OSS Note has an automated check utility to this:

Note 1171650 - Automated Oracle DB parameter check

Thanks,

-----Original Message-----

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org]
On Behalf Of Blanchard William
Sent: Friday, December 12, 2008 7:44 AM
To: Allen, Brandon
Cc: oracle-l_at_freelists.org
Subject: RE: 10g slowdown

Unfortunately, there aren't any. The SAP Admin said that the explain plan looks the same as it was before (using the same index).

William

-----Original Message-----

From: Allen, Brandon [mailto:Brandon.Allen_at_OneNeck.com] Sent: Friday, December 12, 2008 9:43 AM
To: Blanchard William
Subject: RE: 10g slowdown

Did you try checking for previous explain plans as previously suggested?

-----Original Message-----

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Blanchard William Sent: Friday, December 12, 2008 8:08 AM
To: Bobak, Mark
Cc: oracle-l_at_freelists.org
Subject: RE: 10g slowdown

SELECT STATEMENT
  NESTED LOOPS

OUTER             1
    TABLE ACCESS                        ZKPACDATA                    BY
INDEX ROWID    1
      Filter Predicates
        AND
          T_00.WERKS='MS'
          T_00.LOEKZ<>'X'
      INDEX                             ZKPACDATA~Z1
RANGE SCAN        1
        Access Predicates
          AND
            T_00.MANDT='010'
            T_00.AUFNR='000012284021'
            T_00.VORNR='6100'
      INDEX                             ZKPACREASONCODES~0
UNIQUE SCAN       0
        Access Predicates
          AND
            T_01.WERKS(+)='MS'
            T_01.REASONCODE=T_01.REASONCODE(+)



William

-----Original Message-----

From: Bobak, Mark [mailto:Mark.Bobak_at_proquest.com] Sent: Friday, December 12, 2008 9:00 AM
To: Blanchard William; Jack van Zanen
Cc: oracle-l_at_freelists.org
Subject: RE: 10g slowdown

Can you post the execution plan?



From: oracle-l-bounce_at_freelists.org [oracle-l-bounce_at_freelists.org] On Behalf Of Blanchard William [William.Blanchard_at_kohler.com] Sent: Friday, December 12, 2008 9:56 AM
To: Jack van Zanen
Cc: oracle-l_at_freelists.org
Subject: RE: 10g slowdown

The query is technically on one table. It uses a join as a filter only. The table is 5.1 million rows (~3.4G) and stays relatively constant.

SELECT t_00.uname, t_00.erdat, t_00.aezeit, t_00.kpackey, t_00.trantype, t_00.lmnga

    FROM sapr3.zkpacdata t_00, sapr3.zkpacreasoncodes t_01     WHERE (t_00.reasoncode = t_01.reasoncode(+)

                AND t_00.werks = t_01.werks(+))
        AND t_00.mandt = '010'
        AND t_00.loekz <> 'X'
        AND t_00.vornr = '6100'
        AND t_00.aufnr = '000012284021'
        AND t_00.werks = 'MS'

This query took 4.5 hours. When I run an explain plan the cost is 1. That's why I'm confused. My initial thought was that there was something locking the table but even that wouldn't necessarily explain the 4.5 hours. The program was run again during a maintenance window and it still took 6 hours.

William



From: jack.van.zanen_at_gmail.com [mailto:jack.van.zanen_at_gmail.com] On Behalf Of Jack van Zanen
Sent: Thursday, December 11, 2008 10:17 PM To: Blanchard William
Cc: oracle-l_at_freelists.org
Subject: Re: 10g slowdown

are you saying that a query on a single table takes 6 hours?

How big is the table in GB/TB?

Jack

2008/12/12 Blanchard William
<William.Blanchard_at_kohler.com<mailto:William.Blanchard_at_kohler.com>>

We have a query that began taking a long time about a week ago. The program, in SAP, ran for 10 - 15 minutes but is now taking about 6 hours. The table has 5.1 million rows. The explain plan shows a simple index range scan. We just reran statistics on the table and all indexes but no luck We are concentrating on the one query that took about 4.75 hours.

Does anyone see something glaring or know of a simple test to locate the problem?

Let me know if you need any other info.

Thank you,

William B.

--

J.A. van Zanen

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http://www.freelists.org/webpage/oracle-l Received on Fri Dec 12 2008 - 13:41:06 CST

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