Re: sys.col_usage$ question

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Mon, 27 Dec 2004 19:19:05 -0000
Message-ID: <014a01c4ec48$eea66820$6702a8c0@Primary>

equality_preds

    colX = 99

equijoin_preds

    t1.colX = t2.coly

The table is used by Oracle in its attempts to do automatic selection of columns that could use histograms. It's on my to-do list to see if it could be helpful for anything else. The main problem with it for analyzing indexing strategies is that you get no clue about multi-column predicates.     

Regards

Jonathan Lewis

http://www.jlcomp.demon.co.uk/faq/ind_faq.html The Co-operative Oracle Users' FAQ

http://www.jlcomp.demon.co.uk/seminar.html Public Appearances - schedule updated Dec 23rd 2004

• Original Message ----- From: "rjamya" <rjamya_at_gmail.com> To: "Oracle Discussion List" <oracle-l_at_freelists.org> Sent: Monday, December 27, 2004 7:06 PM Subject: sys.col_usage$ question

Maybe I am being little bit clueless (blame that on Eggnog) but what's the difference between the columns equality_preds and equijoin_preds in sys.col_usage$??

Has anyone attempted better indexing methodology based on this table? We have got a bit of re-engineering going on and came to this table when analyzing index usage.

TIA
Raj

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http://www.freelists.org/webpage/oracle-l Received on Mon Dec 27 2004 - 13:15:38 CST