Re: Critical performance problems on large databases

On Thu, 11 Apr 2002, Bruce Momjian wrote:

> Gunther Schadow 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.
> >
> >
> > That is interesting. I haven't even dared to ask for this.
> > Did you contribute that partial sorting code to postgresql?
>
>
> We have the TODO item, but the code is not written yet.
>

Actually, we have libpsort for partial sorting and very crude patch for 7.1
Jan and Tom were not optimist about that patch, so we need one bright
person who could incorporate the idea of partial sorting and current sources
and satisfy core developers. We have no time, unfortunately

>

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