RE: Migration from 8i to 11g

Agreed, definitely check your performance and queries. We heavily used RBO 
(lots of +RULE) hints; however, we were fortunate find very few queries that 
didn't perform well after migrating from 8i to 11.2, many of those were simply 
tunes using the SQL Performance analyzer (and were moved to prod from test - 
using SQL Plan  baselines - 
http://tinky2jed.files.wordpress.com/2011/04/making-plans-with-11g-and-not-leaving-them-behind.pdf
 )

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On 
Behalf Of Rodd Holman
Sent: Wednesday, March 07, 2012 11:55 AM
To: 'oracle-l@xxxxxxxxxxxxx' (oracle-l@xxxxxxxxxxxxx)
Subject: Re: Migration from 8i to 11g

I second this.  We migrated from 9i to 10g in 2007.  Oracle had significantly 
changed/re-written the CBO.  Things that used to fly, crawled.  There is 
definitely a post migration need to stress test your queries, and user adhoc 
queries if they are allowed.
Rodd Holman

On Wed, Mar 7, 2012 at 12:33 PM, Dennis Williams < 
oracledba.williams@xxxxxxxxx> wrote:

> David, (resending without quoting prior posts) Does your applications 
> on 8i use RBO or CBO? Even if it uses CBO, the query execution plans 
> may differ in 11g. When we migrated some critical apps from 8i to 10g 
> a few years ago (a direct upgrade) that was the main source of issues.
>
> Dennis Williams
>
>
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