Re: Tunning Select and Where statements

Yes. Look up the subject "hints" in your oracle doc. There's one that will force no index usage.

Jay Scheiner wrote:

> Is there a way to tell the query to avoid the index? I have worked on a
> mainframe (Unisys DMSII) database where you can either process through the
> index only (if all the values you want are in the index), through the data
> via the index, or just through the table space itself.
>
> You may also reply to jxs at wolpofflaw dot com (no spam).
>
> Thanks.
>
> Riccardo Ferrari wrote in message <7u4o7v$lpk$1_at_nslave1.tin.it>...
> >I suppose you have a B-tree index on 'age'. In this case your index is not
> >enough selective. Sometime a full scan of the table is better than an
> access
> >to the index followed by an access by ROWID to the table.
> >In the second case you have a performance improvement because you avoid the
> >second access by rowid. The name infact is already in the index segment.
> >If your table is really large you should try to use an hash index on age to
> >speed up your query.
> >Ric
Received on Fri Nov 12 1999 - 11:56:30 CST