Re: Creating indexes on a large table

From: Sybrand Bakker <postbus_at_sybrandb.demon.nl>
Date: Tue, 02 Aug 2005 00:04:32 +0200
Message-ID: <6v6te1haivu4bd6q8acnmvca9cngtt1nic@4ax.com>

On 1 Aug 2005 14:33:24 -0700, "prg" <prmail_at_gmail.com> wrote:

>David,
>
> I am using 10.1.0. How can i find out if I am using CBO or not. I
>presume that after 9i, oracle is always using cbo rather than rbo.
>
>Regards,
>prg

10g will use the CBO even if you never analyzed your tables. However in that case, it will simply estimate all the required statistics. You can simply verify whether you have statistics by running select owner, count(*) from dba_tables where num_rows is not null group by owner

IMO, indexing all columns is a recipe for disaster. The chance the optimizer chooses incorrect indexes will increase by this policy.

--
Sybrand Bakker, Senior Oracle DBA

Received on Mon Aug 01 2005 - 17:04:32 CDT