Re: Oracle Myths

In article <f369a0eb.0205221207.64d0538_at_posting.google.com>, you said (and I quote):
>
> Could be very insignificant unless in a CPU-starved mode. With index
> compression tipping the I/O balance this is even less of an issue now.

Exactly. I'd rather have a concatenated key that helps for aggregate queries such as the one below than one that might help me on 1 or 2 I/Os here and there and nothing for aggregates.

> > select status,sum(cur_amount)
> > from agltransact
> > group by status;
> >
>
> A good example, allows Oracle to use FFS when you have a concatenated index.
> This type of quries should be anticipated. Seen too many of them.
>

With or without the least->most order of concatenation, the FFS may be picked up. With the difference that least->most will be considerably faster (sometimes by various orders of magnitude, particularly with Peoplesoft) for ANY aggregate query such as this. I'd rather pay a small price for some single row queries and have the benefit of the much faster weekly or EOD queries/updates.

-- 
Cheers
Nuno Souto
nsouto_at_optushome.com.au.nospam