Re: One-field INDEX performance VS multiple fields index

From: Sybrand Bakker <postmaster_at_sybrandb.demon.nl>
Date: Sun, 1 Aug 1999 23:22:42 +0200
Message-ID: <933542559.9598.0.pluto.d4ee154e@news.demon.nl>

Hi Michael,

The main difference is between unique and non-unique indexes. In your case I would expect at least a bigger index in terms of blocks. There would be only a disadvantage for the composite index when the B-tree would also get higher.
My 2 cts vote is for the single column index.

Hth,

Sybrand Bakker, Oracle DBA
<michael_bialik_at_my-deja.com> wrote in message news:7o2c7o$cm6$1_at_nnrp1.deja.com...
> Hi.
>
> Is there any difference accessing Oracle table through
> index containing one field ( NUMBER(8)) only or through another
> index containing 5 or 6 fields ( including VARCHAR2 ) assuming
> that the number of selected rows is equal in both cases?
>
> I couldn't find any reference in Oracle documentation.
>
> Thanx. Michael.
>
>
> Sent via Deja.com http://www.deja.com/
> Share what you know. Learn what you don't.
Received on Sun Aug 01 1999 - 16:22:42 CDT