Re: CUDA Sorting

On Mon, 2011-09-19 at 15:12 +0100, Greg Stark wrote:
> On Mon, Sep 19, 2011 at 1:11 PM, Vitor Reus <vitor(dot)reus(at)gmail(dot)com> wrote:
> > Since I'm new to pgsql development, I replaced the code of pgsql
> > qsort_arg to get used with the way postgres does the sort. The problem
> > is that I can't use the qsort_arg_comparator comparator function on
> > GPU, I need to implement my own. I didn't find out how to access the
> > sorting key value data of the tuples on the Tuplesortstate or
> > SortTuple structures. This part looks complicated because it seems the
> > state holds the pointer for the scanner(?), but I didn't managed to
> > access the values directly. Can anyone tell me how this works?

....

> With the GPU I'm curious to see how well
> it handles multiple processes contending for resources, it might be a
> flashy feature that gets lots of attention but might not really be
> very useful in practice. But it would be very interesting to see.

There are cases where concurrency may not be that important like some
specialized OLAP loads where you have to sort, for example finding a
median in large data sets.

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Hannu Krosing
PostgreSQL Unlimited Scalability and Performance Consultant
2ndQuadrant Nordic
PG Admin Book: http://www.2ndQuadrant.com/books/