Re: how come oracle is using only one of my indexes?

From: Ian Brown <browni_at_globalnet.co.uk>
Date: Mon, 23 Jul 2001 21:25:05 +0100
Message-ID: <tlp1jok1p2md8f@xo.supernews.co.uk>

"DrowningPeople" <turboridelover_at_yahoo.com> wrote in message news:dc7ccafd.0107231136.5952d415_at_posting.google.com...
> I have a table with 12 columns, and there is an index on each of them.
> Now I have a query that involves all the 12 columns. However, oracle
> only makes use of one of the indexes. Why is it? What should I do to
> make oracle uses more of my indexes?
>
> Thank you.

As I understand it Oracle can only use one index to access a table and must choose (or be told in a HINT) which one to use. However, an index can be based on multiple columns which may allow a more efficient query.

Hth,

Ian Brown Received on Mon Jul 23 2001 - 15:25:05 CDT