On Mon, Nov 5, 2012 at 1:44 PM, Jeff Janes <jeff.ja...@gmail.com> wrote: >> Well, I'm pretty sure that having more work_mem is a good thing (tm) >> normally ;-) > > In my experience when doing sorts in isolation, having more work_mem > is a bad thing, unless it enables you to remove a layer of > tape-merging. I always blamed it on the L1/L2 etc. levels of caching.
Blame it on quicksort, which is quite cache-unfriendly. Perhaps PG should consider using in-memory mergesort for the bigger chunks. -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
