Re: SOS what should I do with this mess?

Joe Sath wrote:
>
> One of my new client, their previous DBA NEVER analyze their tables even
> though he set his optimizer_mode = choose, the whole production is running
> as RULE based.
>
> When I analyzed the database( excepte sys,system), the whole database become
> so slow, I have to delete all the statistics in order for the production to
> go on.
>
> What should I do with it? Leave it running as rule based? It is kind of
> pain that you can not take advantage of cost optimizer.
>
> What steps should I take to convert it smoothly to cost based one?
>
> Thanks for your help

If the system is not suffering from a lot of parsing, you could capture and store the outlines under rule. Then you analyze the tables etc, and slowly migrate to cbo by removing (and/or reinstating as the case may be) the stored outlines.

hth
connor

-- 
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Connor McDonald

http://www.oracledba.co.uk

"Some days you're the pigeon, some days you're the statue..."