RE: A question about performance

Hi,

CASE 1 is the correct one. Why use the index first and for every entry go to the blocks on te table?
You have to full scan the data table blocks anyway, so just do it without wasting time (and resources) reading the index and - after - going to the table in a scattered way.

Anyway probe it and let us know the results.

HTH Joselu
www.OraEs.com
Madrid (SPAIN)

> -----Mensaje original-----
> De: Weerd de E.C. Kirsten [SMTP:Kirsten.deWeerd_at_Oranjewoud.nl]
> Enviado el: miércoles 21 de junio de 2000 13:58
> Para: Multiple recipients of list ORACLE-L
> Asunto: RE: A question about performance
>
> I think performance will be about the same. You select all records in the
> table, no matter which statement you use. So evidently, Oracle will
> process
> every row no matter what.
>
> Greets,
>
> Kirsten
>
> > -----Original Message-----
> >
> > Hi All:
> > There is a question about performance.
> > Table name : subscriber , primary key : subscr_id , with
> > over 5000000 records .
> >
> > CASE 1 : select *
> > from subscriber ;
> > (FULL TABLE SCAN)
> >
> > CASE 2 : select *
> > from subscriber
> > where subscr_id > 0 ;
> > (USE INDEX)
> >
> > Could anyone tell me which ones performance is better , or
> > they are the same ??
> >
> > Thank you in advance.
> >
> >
> > Tiffany
> > E-mail tiffanydu_at_pcdc.com.tw
> >
> --
> Author: Weerd de E.C. Kirsten
> INET: Kirsten.deWeerd_at_Oranjewoud.nl
>
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Received on Wed Jun 21 2000 - 06:28:14 CDT