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

From: Adriaan Nortje <gandalf_at_nol.co.za>
Date: Wed, 22 Aug 2001 20:16:53 +0200
Message-ID: <3b83f699$0$228@hades.is.co.za>


if you ever did any explain plans on your queries you would find that Oracle only needs 1 index for any search.
I mean that oracle writes away a relational location of each row for each index defined in your index's table space. Thus, cross-referencing of index are more intensive than just using 1 index.

"DrowningPeople" <turboridelover_at_yahoo.com> wrote in message news:dc7ccafd.0108220921.871c2e8_at_posting.google.com...
> I have a table with 12 columns, and I have thousands of random queries
> that could involve any different number of different columns. I have
> an index for each column. For those "AND-EQUAL" operations, I expect
> oracle to mergs lists of data returned from multiple index scans. But
> oracle is always using only one index (different one everytime). Can
> anyone tell me why?
>
> Thanks alot
Received on Wed Aug 22 2001 - 13:16:53 CDT

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