Re: indexing

Wolfgang,

How could I have forgotten that one - it's one of my "dire warning" slides: Oracle got it half-right in 10.2.0.3, before doing it properly in 11.1.0.6

Regards

Jonathan Lewis
http://jonathanlewis.wordpress.com/all-postings

Author: Oracle Core (Apress 2011)
http://www.apress.com/9781430239543

• Original Message ----- From: "Wolfgang Breitling" <breitliw_at_centrexcc.com> To: <jonathan_at_jlcomp.demon.co.uk> Cc: "oracle-l List" <oracle-l_at_freelists.org> Sent: Wednesday, February 20, 2013 2:09 PM Subject: Re: indexing

I respectfully beg to differ. It is probably correct for the "sanity check" you are referring to. I was talking about the basic cardinality estimate calculation where the optimizer can use the distinct_keys statistics of an index to calculate the "single table cardinality" but then decide not to use the index in the access plan - perhaps because of this more accurate estimate:

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http://www.freelists.org/webpage/oracle-l Received on Wed Feb 20 2013 - 17:58:29 CET