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

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

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