For tables that have indexes at one column per index (for the columns that
have indexes), is there any benefit (apart from possibly storing data more
efficiently) to combine the columns into one index? Could it save an I/O or
two, for example?

Background - we just stopped supporting Oracle 7 so we haven't (yet)
implmenented bitmap indexes, IOT's, etc.

Thanks,
dsb

On Tue, 1 Jul 2003 12:22:18 -0700, "dsb" <dana@iqms.com> wrote:

>For tables that have indexes at one column per index (for the columns that
>have indexes), is there any benefit (apart from possibly storing data more
>efficiently) to combine the columns into one index? Could it save an I/O or
>two, for example?
>
>Background - we just stopped supporting Oracle 7 so we haven't (yet)
>implmenented bitmap indexes, IOT's, etc.
>
>Thanks,
>dsb
>


Oracle is capable of merging indexes on the fly.
So the answer to generic questions like this one is, as usual: it
depends.
The problem with your approach is that you may likely setup an
incorrect column as 'leading', so your index isnt' being used anyway.



Sybrand Bakker, Senior Oracle DBA

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