Re: Performance with ORDER BY !!!

From: <karsten_schmidt8891_at_my-deja.com>
Date: Mon, 06 Dec 1999 10:01:31 GMT
Message-ID: <82g1hq$27t$1@nnrp1.deja.com>

Hi,
You have to decide, whether you want to use an index for sorting, or to evaluate the where predicate.
By default, the optimiser will prefer to use an index for the predicate.
In general, this is the better choice, based on the assumption, the predicate selects a small subset of your table.

Karsten

In article <384A9BE4.1703510D_at_ibm.net>, David Hart <dghart_at_ibm.net> wrote:
> Create an index on the column order you need and use an index_asc()
> hint. The rows will be returned in index order.
>
> D.
>
> Franz Mueller wrote:
> >
> > If I have a query that returns, say 500 rows. I have good indices on
> > the WHERE clauses and the answer time is OK. The problem is that in
> > practice you always want to show the results sorted
(alphabetically).
> > If you add ORDER BY <something> the performance descreases
> > dramatically. What can be done?
>

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Before you buy. Received on Mon Dec 06 1999 - 04:01:31 CST