Josh Berkus writes: > On 02/26/2015 05:50 PM, Fabrízio de Royes Mello wrote: >> >> On Thu, Feb 26, 2015 at 10:27 PM, Andres Freund <and...@2ndquadrant.com >> <mailto:and...@2ndquadrant.com>> wrote: >>> >>> On 2015-02-26 20:23:33 -0500, Tom Lane wrote: >>> > >>> > I seem to recall somebody demo'ing a simulated-annealing GEQO >> replacement >>> > at PGCon a couple years back. It never got to the point of being a >>> > submitted patch though. >>> >>> Yea, it was Jan Urbański (CCed). >>> >> >> And the project link: https://github.com/wulczer/saio > > So what w'ere saying, Grzegorz, is that we would love to see someone > pick this up and get it to the point of making it a feature as a GSOC > project. I think if you can start from where Jan left off, you could > actually complete it.
Sorry, late to the party. Yes, I wrote a GEQO replacement that used simulated annealing for my Master thesis. It got to a point where it was generating plans similar to what GEQO outputs for small queries and better plans for very large ones. The thesis itself is here: https://wulczer.org/saio.pdf and the linked GitHub repo contains source for the PGCon presentation, which gives a higher-level overview. The big problem turned out to be writing the step function that generates a new join order from a previous one. Look for the "Simulated Annealing challenges" and "Moves generator" chapters in my thesis, which are the only interesting ones :) If you'd like to pick up where I left, I'd be more than happy to help in any ways I can. Best, Jan -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
