Re: Critical performance problems on large databases

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.

>

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