Rick Otten <rottenwindfish@xxxxxxxxx> writes: > On Thu, Jan 7, 2016 at 12:51 PM, Scott Rankin <srankin@xxxxxxxxx> wrote: >> Winner! Both of those settings were set to always, and as soon as I >> turned them off, the query times smoothed right out. > Is this generally true for all PostgreSQL systems on Linux, or only for > specific use cases? It's fairly well established that the implementation of transparent huge pages in Linux kernels from the 2.6-or-so era sucks, and you're best off turning it off if you care about consistency of performance. I am not sure whether modern kernels have improved this area. I think you can get an idea of how big a problem you have by noting the accumulated runtime of the khugepaged daemon. (BTW, it would likely be a good thing to collect some current wisdom in this area and add it to section 17.4 of our docs.) regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
