Re: CBO question ?

Resending because of overquoting.

Don't know if it is different for partitioned tables, but here are defaults (nothing is said whether it is or is not for partitioned tables and indexes, probably someone smarter will add some clever word here):
http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96533/stats.htm#25056

But if you haven't analyzed tables you can use dynamic_sampling either as hint or initialization parameter optimizer_dynamic_sampling. Here are link for various dynamic_samling levels http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96533/hintsref.htm#11792

If I remeber correctly then for 9i optimizer_dynamic_sampling default value is 1, for 10g it is 2.

Gints

2006/3/2, Ram K <lambu999_at_gmail.com>:
>
> If Oracle is going to use CBO for partitioned tables by default, how does it
> work in the case of absence of statistics?
> Does it collect statistics at runtime? Usually partitioned tables tend to
> be big. I am interested to know how it works.
> Thanks.
>
> Ram.
>

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