On Wednesday 23 December 2009 02:23:55 Jan Urbański wrote: > Hi, > > I've been playing with using a Simulated Annealing-type algorithm for > determinig join ordering for relations. Very cool.
> Lastly, I'm lacking good testcases or even a testing approach: I'm > generating silly queries and looking at how they get optimised, but if > someone has a real dataset and examples of joins that cannot be planned > with the standard planner, I would be interested to compare the results > my prototype gets with those produced by GEQO. If you want to see some queries which are rather hard to plan with random search you can look at http://archives.postgresql.org/message- id/200907091700.43411.and...@anarazel.de which tom analyzed and improved here http://archives.postgresql.org/message- id/17807.1247932...@sss.pgh.pa.us They are hard to plan because they have lots and lots of join order restrictions. While this example is rather extreme I have found quite many such queries so far. Robert had another example in 603c8f070911271205r4d4534edt1cebcb76ff506...@mail.gmail.com that might be interesting. Andres -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
