Re: How to calculate cardinality for inequality in WHERE
- From: Martin Klier <usn@xxxxxxxxx>
- To: jonathan@xxxxxxxxxxxxxxxxxx
- Date: Fri, 12 Jul 2013 16:55:41 +0200
Hi Jonathan,
I tried a few things with various cardinality and inequalities with
known predicate on this table, and it seems that the 5% thing is
correct: If card. is 5% or round this, the plan looks the same, and
estimates are quite similar.
Thanks for the hint & clarification.
Best regards
Martin
Jonathan Lewis schrieb:
>
> Off the top of my head - and without checking it for 11g, Oracle treats this
> as:
> column < unknown
> which means 5% of current cardinality.
>
> Short of a profile or cardinality hint there is no real alternative to the
> type of solution you've used.
>
> Regards
> Jonathan Lewis
>
>
> ________________________________________
> From: oracle-l-bounce@xxxxxxxxxxxxx [oracle-l-bounce@xxxxxxxxxxxxx] on behalf
> of Martin Klier [Martin.Klier@xxxxxxxxxx]
> Sent: 11 July 2013 14:27
> To: oracle-l@xxxxxxxxxxxxx
> Subject: How to calculate cardinality for inequality in WHERE
>
> Hello listers,
>
> today again, a question merely for understanding than for solving a
> current problem.
>
> DB-Version 11.2.0.3.6 SE on Linux x86_64
>
> select * from TABLE
> where QTY1 < QTY2;
>
> There are approx. 1.5 million rows in this table.
> QTY1 < QTY2 means 0, 1 or 2 rows at max--
> //www.freelists.org/webpage/oracle-l
>
>
>
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