Re: analyze index and cost

Hi ,

The optimizer does a full table scan when I compute statistics , but if there is no statistics ,the optimiser uses that index , now this is my point Why the optimizer does that , I though it would be faster when I compute statistics but it is not ,

Regards,
Achkar

damorgan <dan.morgan_at_ci.seattle.wa.us> wrote in message news:<3C7FAAE9.C3F26803_at_ci.seattle.wa.us>...
> Excellent advise. If that doesn't solve it post the query, the explain plan,
> a list of indexes on the table(s), and the number of rows.
>
> Are you using any hints?
>
> Daniel Morgan
>
>
>
> santosh sharma wrote:
>
> > did you compare the explain plan before and after compute stat ? It will
> > point you why this is happening.
> >
> > HTh
> > santysharma
> >
> > "achkar" <kachkar_at_tablimited.com.au> wrote in message
> > news:acb78eab.0202281707.34303a16_at_posting.google.com...
> > > Hi All ,
> > >
> > > I have a big query , it takes 70 min to run , cost is 94819 , when I
> > > create and index ( XXX ) on one of the tables , the cost drops down to
> > > 53770 and takes 30 min to run , but when I do this : analyze index XXX
> > > compute statistics , the cost goes up to 94819 again , I dont
> > > understand why?
> > >
> > > thanks in advance
Received on Sun Mar 03 2002 - 18:19:38 CST