On 25 November 2015 at 00:33, Peter Geoghegan <p...@heroku.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/> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
