Re: Hint cardinality for predicate
From: Marcin Przepiorowski <pioro1_at_gmail.com>
Date: Wed, 12 May 2010 20:58:06 +0100
Message-ID: <AANLkTinlUNxgVUwxCqrETbWoiP6Otx7dcZbOCtmmWPTo_at_mail.gmail.com>
On Wed, May 12, 2010 at 8:53 PM, Ilia Kantor <iliakan_at_gmail.com> wrote:
> Hello,
>
> I have a multi-predicate query like:
>
> SELECT * FROM table WHERE
> a BETWEEN 5 and 10
> and
> b in (3,4,5)
> and c in (9)
> ...
>
> Unfortunately, optimizer is not very good at estimating cardinalities.
> Columns are somewhat intercorrelated and "multiple column stats"
> feature does not fix that.
>
> Although, I gather my own stats which give me exact idea for
> selectivity of each predicate.
> How can I pass this information to optimizer?
>
Date: Wed, 12 May 2010 20:58:06 +0100
Message-ID: <AANLkTinlUNxgVUwxCqrETbWoiP6Otx7dcZbOCtmmWPTo_at_mail.gmail.com>
On Wed, May 12, 2010 at 8:53 PM, Ilia Kantor <iliakan_at_gmail.com> wrote:
> Hello,
>
> I have a multi-predicate query like:
>
> SELECT * FROM table WHERE
> a BETWEEN 5 and 10
> and
> b in (3,4,5)
> and c in (9)
> ...
>
> Unfortunately, optimizer is not very good at estimating cardinalities.
> Columns are somewhat intercorrelated and "multiple column stats"
> feature does not fix that.
>
> Although, I gather my own stats which give me exact idea for
> selectivity of each predicate.
> How can I pass this information to optimizer?
>
Hi,
What database version ?
Did you try change gathering statistic from estimating to calculating
and use histograms ?
-- Marcin Przepiorowski http://oracleprof.blogspot.com -- http://www.freelists.org/webpage/oracle-lReceived on Wed May 12 2010 - 14:58:06 CDT