Re: Critical performance problems on large databases

Well,

I've got several responses..
I'm far from office and has slow and unstable connection, so I
will return to this topic next week.

    Oleg
On Thu, 11 Apr 2002, Gunther Schadow wrote:

> Oleg Bartunov wrote:
>
> > On Thu, 11 Apr 2002, Bruce Momjian wrote:
> >
> >
> >>Oleg Bartunov wrote:
> >>
> >>>The big issue with LIMIT,OFFSET is that it still use all rows
> >>>for sorting. I already suggested to use partial sorting to avoid
> >>>sorting all rows if one selected only first 20 row, for example.
> >>>It's very important for Web applications because web users usually
> >>>read first 1-2 pages. Our experimnets have shown 6 times performance
> >>>win when using partial sorting.
> >>>
> >>We do have this TODO item:
> >>
> >>    * Allow ORDER BY ... LIMIT to select top values without sort or index
> >>      using a sequential scan for highest/lowest values
> >>
> >>
> >
> > looks too complex to me :-) I like partial sorting, but it's not
> > important.
>
>
> Oleg, I might argee. I might even take some of this one. But I
> think a first step would be for you to put your libpsort and
> the pacth "out there" so that someone could just look and try
> and see if taking the time to do what needs to be done is feasible
> with this. If you can put up your lib and patch and documentation
> (even crude notes)) onto a web site, that would be a good start.
>
> regards
> -Gunther
>
>
>
>
>

    Regards,
        Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83