Hello Mateusz

But PER_IDENTI is the Primary Key, why Firebird needs a two-pass proccess?

Greetings.

Walter.

On Fri, Mar 1, 2013 at 5:51 AM, Mateusz Loskot <mateusz@...> wrote:

> **
>
>
> On 1 March 2013 04:37, W O sistemas2000profesional@...> wrote:
> > Somebody knows why there are a difference so big?
> >
> > I have a table with 3.600.000 rows more or less.
> >
> > Writing:
> > SELECT * FROM V_ABM_PERSONAS V WHERE V.PER_IDENTI > 0 ROWS 1 TO 100
> >
> > takes 2.656 seconds (less than 3 seconds)
> >
> > Writing:
> > SELECT * FROM V_ABM_PERSONAS V ORDER BY V.PER_IDENTI ROWS 1 TO 100
> >
> > takes more than 11 minutes!!!! (bored, I did cancel the execution)
>
> Think of it as single-pass versus two-pass processing.
>
> Best regards,
> --
> Mateusz Loskot, http://mateusz.loskot.net
>
>
>


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