On 6 February 2014 18:21, Jeff Janes <jeff.ja...@gmail.com> wrote: > On Tue, Feb 4, 2014 at 2:22 PM, Jeremy Harris <j...@wizmail.org> wrote: >> >> The attached patch replaces the existing siftup method for heapify with >> a siftdown method. Tested with random integers it does 18% fewer >> compares and takes 10% less time for the heapify, over the work_mem >> range 1024 to 1048576. > > > Thanks for working on this.
+1 Your patch isn't linked properly from the CF manager though. If you like patches like this then there's a long(er) list of optimizations already proposed previously around sorting. It would be good to have someone work through them for external sorts. I believe Noah is working on parallel internal sort (as an aside). There's also an optimization possible for merge joins where we use the output of the first sort as an additional filter on the second sort. That can help when we're going to join two disjoint tables. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers