Re: RBO to CBO

From: Howard J. Rogers <hjr_at_dizwell.com>
Date: Thu, 30 Dec 2004 14:56:29 +1100
Message-ID: <41d37c6f$0$11881$afc38c87@news.optusnet.com.au>

Oradba Linux wrote:
> Any major/minor issues to watch out for during the conversion especially
> with regards to sql written specifically to RBO

Yup, a fairly major point: code written specifically for the RBO usually ends up performing abysmally under the CBO. Unless you're planning to effectively start from scratch, and gather execution plans for every SQL statement, you can expect trouble.

If you're not effectively going to re-write your app. from scratch, and you're generally happy with the way it's been performing under the RBO, then you might want to investigate the use of Stored Outlines: capture the outlines under the RBO, and then use them under the CBO. You should end up using the same eexecution plans under the new model as you did under the old.

Good luck.

Regards
HJR Received on Wed Dec 29 2004 - 21:56:29 CST