Re: Re[2]: [HACKERS] \dt and disk access

I don't believe the data is almost-sorted.

>
>
> How about using a heap sort?  Works in order of magnitude better on
> almost-sorted data than the quick sort.
>
> I have the code if anyone is interested. (C++, though.)
>
> Leo
> _______________________________________________________________________________
> Subject: Re: [HACKERS] \dt and disk access
> From:    <maillist%candle.pha.pa.us@interlockp.lubrizol.com> at LZ-INTERNET
> Date:    6/23/97  10:16 PM
>
> > >From what I remember, the quick sort algorithm works just as fast on
> > sorted data as on unsorted data.  In other words, the algorithm does not
> > take advantage of the fact that the data is sorted.
> >
> > On the other hand, if you go to something like bubble sort, it will
> > work faster than quick sort if the data is sorted and you are adding one
> > more item, but on unsorted data it takes an enormously longer length of
> > time to sort a large list.
> >
>
> One thing I am going to look into is replacing the btree-build in the
> current psort with a qsort of HeapTuple pointers.
>
> --
> Bruce Momjian
> maillist@candle.pha.pa.us
>
>
>
>
>


- --
Bruce Momjian
maillist@candle.pha.pa.us

------------------------------