Обсуждение: AW: Some Improvement

> I still think there must be sorting going on, as the result 
> is returned
> instantly if you remove the ORDER BY. I don't know - I do think it's
> much better now.

Are you doing the exact query I wrote for you ?
That is:order by mail_list desc, mail_date desc

explain should tell you if it does a sort. There should not be a difference
with 
or without the order by.
Hiroshi, I think you implemented the backwards index scan ?
Otherwise he would need to recreate the index as(mail_list desc, mail_date desc)

Sorry for the inconvenience
Andreas

> -----Original Message-----
> From: pgsql-hackers-owner@hub.org [mailto:pgsql-hackers-owner@hub.org]On
> Behalf Of Zeugswetter Andreas SB
> 
> > I still think there must be sorting going on, as the result 
> > is returned
> > instantly if you remove the ORDER BY. I don't know - I do think it's
> > much better now.
> 
> Are you doing the exact query I wrote for you ?
> That is:
>     order by mail_list desc, mail_date desc
> 
> explain should tell you if it does a sort. There should not be a 
> difference
> with 
> or without the order by.
> Hiroshi, I think you implemented the backwards index scan ?

Yes,but I didn't implement backwards index path for cost estimate.

Regards.

Hiroshi Inoue
Inoue@tpf.co.jp

"Hiroshi Inoue" <Inoue@tpf.co.jp> writes:
>> Hiroshi, I think you implemented the backwards index scan ?

> Yes,but I didn't implement backwards index path for cost estimate.

I did ... but I didn't get it quite right :-( ... see later message ...
        regards, tom lane