Re: indexing

From: Jonathan Lewis <>
Date: Wed, 20 Feb 2013 16:58:29 -0000
Message-ID: <2870B1CB1919460BA465B4A86AE7C7B2_at_Primary>


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


Jonathan Lewis

Author: Oracle Core (Apress 2011)

  • Original Message ----- From: "Wolfgang Breitling" <> To: <> Cc: "oracle-l List" <> 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:

-- Received on Wed Feb 20 2013 - 17:58:29 CET

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