On Fri, Aug 8, 2014 at 4:16 AM, Jeff Davis <pg...@j-davis.com> wrote: > I wasn't able to reproduce your results on my machine. At -s 300, with > maintenance_work_mem set high enough to do internal sort, it took about > 40s and I heard some disk activity, so I didn't think it was a valid > result. I went down to -s 150, and it took around 5.3s on both master > and memory-accounting. > > Either way, it's better to be conservative. Attached is a version of the > patch with opt-in memory usage tracking. Child contexts inherit the > setting from their parent.
I repeated my tests with your v3 patch. Here are the new results: master, as of commit a4287a689d10bd4863e3dfbf9c4f232feeca0cdd: 2014-08-14 16:45:24 UTC  LOG: internal sort ended, 1723933 KB used: CPU 2.44s/11.52u sec elapsed 16.68 sec 2014-08-14 16:46:34 UTC  LOG: internal sort ended, 1723933 KB used: CPU 2.63s/11.65u sec elapsed 16.94 sec 2014-08-14 16:47:26 UTC  LOG: internal sort ended, 1723933 KB used: CPU 2.63s/11.48u sec elapsed 16.85 sec memory-accounting-v3, on top of the aforementioned master commit: 2014-08-14 16:46:05 UTC  LOG: internal sort ended, 1723933 KB used: CPU 2.52s/12.16u sec elapsed 17.36 sec 2014-08-14 16:47:00 UTC  LOG: internal sort ended, 1723933 KB used: CPU 2.52s/11.90u sec elapsed 17.11 sec 2014-08-14 16:47:51 UTC  LOG: internal sort ended, 1723933 KB used: CPU 2.52s/11.98u sec elapsed 17.31 sec It appears to me that the performance characteristics for this version are not significantly different from version 1. I have not looked at the code. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers