On Wed, Nov 25, 2015 at 12:33 AM, Peter Geoghegan <p...@heroku.com> wrote: > On Tue, Nov 24, 2015 at 3:32 PM, Simon Riggs <si...@2ndquadrant.com> wrote: >> My feeling is that numbers rarely speak for themselves, without LSD. (Which >> numbers?) > > Guffaw.
Actually I kind of agree. What I would like to see is a series of numbers for increasing sizes of sorts plotted against the same series for the existing algorithm. Specifically with the sort size varying to significantly more than the physical memory on the machine. For example on a 16GB machine sorting data ranging from 1GB to 128GB. There's a lot more information in a series of numbers than individual numbers. We'll be able to see whether all our pontificating about the rates of growth of costs of different algorithms or which costs dominate at which scales are actually borne out in reality. And see where the break points are where I/O overtakes memory costs. And it'll be clearer where to look for problematic cases where the new algorithm might not dominate the old one. -- greg -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
