I don't think sy had any issue with what you had suggested, it was
suggestions 5 onwards that are suspect.
--
Niall Litchfield
Oracle DBA
Audit Commission UK
"Ryan Gaffuri" <rgaffuri_at_cox.net> wrote in message
news:1efdad5b.0305290306.568c50ea_at_posting.google.com...
> I have no diea where this stuff with select 1 from dual comes from. I
> have never seen that.
>
> however moving code to sub-queries and deciding to use an exists
> clause works well and is documented on asktom and in harrisons sql
> tuning book. It has worked for me before.
>
> most of the improvements I have seen with the CBO is by considering
> the relative table sizes and how many rows you will return. There are
> several approaches that are better or worse depending on that.
>
> Since his 'OR' is probably what is killing him. spinning it to a
> sub-query may help.
>
> Sybrand Bakker <gooiditweg_at_sybrandb.demon.nl> wrote in message
news:<j06bdvsprsun9o8c6o03907dti86p258el_at_4ax.com>...
> > On Wed, 28 May 2003 17:28:18 -0700, "Mikito Harakiri"
> > <mikharakiri_at_ywho.com> wrote:
> >
> > >Also consider the following:
> > >5. Change the order of the tables in the from clause. Try all the
> > >permutations.
> > >6. Add "and exist(select 1 from dual)". Mix it with " and exist(select
2
> > >from dual)" sparingly.
> > >7. Try capital letters in the table names -- optimiser respect those
more.
> > >8. Start playing with init.ora parameters. There are too many of those
to
> > >check all the permutations, but give it a shot.
> >
> >
> > He is running CBO, isn't he? So what will the suggestions above do?
> > Apart from introducing stupid MYTHS, exactly NOTHING!!!!!
> >
> >
> > Sybrand Bakker, Senior Oracle DBA
> >
> > To reply remove -verwijderdit from my e-mail address
Received on Thu May 29 2003 - 06:27:35 CDT
