Re: EXPLAIN PLAN : better with RULE!

From: Steve Mitchell <stevem_at_hdcsi.com>
Date: Mon, 22 Jul 2002 17:06:03 GMT
Message-ID: <%XW_8.275$gj.10765458@newssvr21.news.prodigy.com>

"Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> wrote in message news:1027158123.29738.1.nnrp-14.9e984b29_at_news.demon.co.uk...
>
> Rather than just fiddling with parameters though, the
> next thing to do is look at the indexes and columns
> that the RBO has used in its plan, and examine the
> statistics stored in user_indexes, user_tab_columns,
> and user_histograms to see why CBO doesn't like
> them. Also check the stats against the real data
> to see if the stats are misleading.
>

Great idea,

Do you know where I might find some reference that would help me understand the statistics stored in user_indexes, user_tab_columns, and user_histograms? I would like to better understand how these fit together to get an idea of why the CBO is ignoring indexes that are obviously a better choice.

> --
> Jonathan Lewis
> http://www.jlcomp.demon.co.uk
>

--steve Received on Mon Jul 22 2002 - 12:06:03 CDT