On Wed, Dec 23, 2015 at 1:03 PM, Jeff Janes <jeff.ja...@gmail.com> wrote: > If we do think it is important to almost never cause regressions at > the default maintenance_work_mem (I am agnostic on the importance of > that), then I think we have more work to do here. I just don't know > what that work is.
My next revision will use grow_memtuples() in advance of the final on-the-fly merge step, in a way that considers that we won't be losing out to palloc() overhead (so it'll mostly be the memory patch that is revised). This can make a large difference to the number of slots (memtuples) available. I think I measured a 6% or 7% additional improvement for a case with a fairly small number of runs to merge. It might help significantly more when there are more runs to merge. -- Peter Geoghegan -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
