Subject | RE: [ib-support] Re: PLAN |
---|---|
Author | Nico Callewaert |
Post date | 2001-05-17T12:47:09Z |
Hi,
Thanks for the answer, but I don't know if I have to agree with you. For
example if you build a JOIN, with a DISTINCT, it will not use a index I
guess. As far as I know DISTINCT cannot use a index ???
Nico
-----Oorspronkelijk bericht-----
Van: alex_vnru@... [mailto:alex_vnru@...]
Verzonden: donderdag 17 mei 2001 14:34
Aan: ib-support@yahoogroups.com
Onderwerp: [ib-support] Re: PLAN
Thanks for the answer, but I don't know if I have to agree with you. For
example if you build a JOIN, with a DISTINCT, it will not use a index I
guess. As far as I know DISTINCT cannot use a index ???
Nico
-----Oorspronkelijk bericht-----
Van: alex_vnru@... [mailto:alex_vnru@...]
Verzonden: donderdag 17 mei 2001 14:34
Aan: ib-support@yahoogroups.com
Onderwerp: [ib-support] Re: PLAN
--- In ib-support@y..., "Nico Callewaert" <ncw@c...> wrote:
> Hi,
>
> I've created a query that is making a SUM of some records.
I've checked
> the PLAN and I noticed that it is using NATURAL sort order. I
guess that
> is normal for aggregate functions ? Is it better to avoid using
SUM then ?
> Performance ?
>
> Thanks a lot,
>
> Nico Callewaert
Hi, Nico. Aggregate or not means nearly nothing for query plan. Plan
is build on join conditions and where clause having in optimizer's
mind (or your, if you explicitly plan your query) existing indexes.
Look at http://www.ibphoenix.com/ibp_quep.html
Best regards.
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