Re: composite index

you could if you use a hint to force use of the Index and see if it saves you time

select /*+ index(index_name) */ *
from .....
where ....

Daniel Morgan <damorgan_at_x.washington.edu> wrote in message news:<1071154705.558544_at_yasure>...
> Laly wrote:
> > Hello,
> >
> >
> > Suppose we have a huge table T(a, b, ...)
> > There is a primary key on (a, b).
> > Can we gain some time on queries like
> > select *
> > from T
> > where a = ...
> > by creating a new nonunique index on column a.
> >
> >
> > Thanks in advance,
> >
> >
> > Laly.
>
> Version number?
>
> Possibly. It is worth testing in a specific situation.
>
> Certainly one on 'b' would be more likely to generate an improvement
> provided the cost of the indexes maintenance isn't larger than the
> improvement.
>
> There is no general rule other than try it and find out.
Received on Thu Dec 11 2003 - 15:43:04 CST