Re: Index usage ??

Connor McDonald <connor_mcdonald_at_yahoo.com> wrote in message news:<3C61B6C5.699E_at_yahoo.com>...
> Ralf wrote:
> >
> > I have the following statement:
> >
> > select max(value1) from table1
> >
> > There is an index "index1 on table1(value1)".
> >
> > The plan for the above statement shows me that the database uses an
> > full index scan and an table access by rowid to retrieve the value.
> > Why does it behave like this ?
> >
> > I tought the index should be sorted ? Then i would navigate at the end
> > of the index, get the value. I wouldn´t do any full index scan and
> > would not go to the table to get the value, because its in the index
> > already.
> >
> > Can someone explain, please ?
> >
> > Ralf
>
> version?
>
> later versions of oracle will/can/may show a 'INDEX (MIN/MAX)' in the
> explain plan which does exactly what you were anticipating.
>
> hth
> connor

Oracle 8.1.7 running on Windows NT
Table has 21000 entries, index has 4000 distinct values

Ralf Received on Thu Feb 07 2002 - 02:41:59 CST