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RE: Rollback Segments on 8.1.7.4

From: Kevin Lange <klange_at_ppoone.com>
Date: Tue, 11 Mar 2003 08:49:42 -0800
Message-ID: <F001.00566362.20030311084942@fatcity.com>


I will have to check your question on 'fewer sorts'.

As far as changes to the SQL statements, there were 1 or 2 sql statements changed in the application because they no longer worked efficiently with the change to 8.1.7. But, on the whole (lets say 98%+ of the time) no changes were made.

-----Original Message-----
Sent: Monday, March 10, 2003 5:39 PM
To: Multiple recipients of list ORACLE-L

Did any of the rollback segment storage parameters (i.e. INITIAL, NEXT, PCTINCREASE, MINEXTENTS, MAXEXTENTS, OPTIMAL) or the number of rollback segments change between 8.0.5 and 8.1.7? Changes to any of these variables could impact the space available for storing inactive undo blocks for read-consistency purposes.

If the answer is "of course not", then here comes the harder question: did the SQL statements change between 8.0.5 and 8.1.7? Not just outright different SQL statements, but even the same SQL statements running with different execution plans? For example, changing explain plans so that SORT-MERGE join is no longer use could have significant impact on ORA-01555, as forcing sorts are one way to minimize SNAPSHOT TOO OLD. Having queries run faster is another way to minimize ORA-01555, so getting rid of SORT-MERGE joins will likely help, but if the performance improvements aren't good enough, then the conversion to HASH or NESTED LOOP joins may allow more ORA-01555 to occur. Have you noticed fewer sorts occurring since 8.0.5?

Just some ideas...

> Evening;
> Has anyone noticed any difference on the way Oracle uses Rollback
Segments
> on 8.1.7.4 versus 8.0.5 ??
>
> Ever since upgrading to 8.1.7.4 from 8.0.5 on our Solaris servers we have
> noticed more SNAPSHOT TOO OLD errors than we used to.
>
> Are there any suggestions as to rollback tuning that has to be done with
> that kind of version move ??
>
> Any help would be appreciated.
>
> Thanks
>
> Kevin
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
> --
> Author: Kevin Lange
> INET: klange_at_ppoone.com
>
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Received on Tue Mar 11 2003 - 10:49:42 CST

Original text of this message

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