Re: Using quicksort for every external sort run

On 25 November 2015 at 00:33, Peter Geoghegan <pg(at)heroku(dot)com> wrote:

> Parallel sort is very important. Robert, Amit and I had a call about
> this earlier today. We're all in agreement that this should be
> extended in that direction, and have a rough idea about how it ought
> to fit together with the parallelism primitives. Parallel sort in 9.6
> could certainly happen -- that's what I'm aiming for. I haven't really
> done preliminary research yet; I'll know more in a little while.

Glad to hear it, I was hoping to see that.

> > How about we commit it with a sort_algorithm = 'foo' parameter so we can
> > compare things before release of 9.6?
>
> I had a debug GUC (like the existing one to disable top-N heapsorts)
> that disabled "quicksort with spillover". That's almost the opposite
> of what you're asking for, though, because that makes us never use a
> heap. You're asking for me to write a GUC to always use a heap.
>

I'm asking for a parameter to confirm results from various algorithms, so
we can get many eyeballs to confirm your work across its breadth. This is
similar to the original trace_sort parameter which we used to confirm
earlier sort improvements. I trust it will show this is good and can be
removed prior to release of 9.6.

--
Simon Riggs http://www.2ndQuadrant.com/
<http://www.2ndquadrant.com/>
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