On Sat, Oct 8, 2016 at 11:27 PM, Fabien COELHO <coe...@cri.ensmp.fr> wrote:
> > Hello Amit. > > Also, given the heavy UPDATE nature of the pgbench test, a non 100% default >>> fill factor on some tables would make sense. >>> >> >> FWIW, sometime back I have seen that with fill factor 80, at somewhat >> moderate client counts (32) on 192 - Hyper Threaded m/c, the >> performance is 20~30% better, but at higher client counts, it was same >> as 100 fill factor. >> > > The 20-30% figure is consistent with figures I collected 2 years ago about > fill factor on HDD, see the beginning run of: > > http://blog.coelho.net/database/2014/08/23/postgresql- > fillfactor-and-update.html > > Although I found that the advantages is reduced after some time because > once a page has got an update it has some free space which can be taken > advantage of later on, if the space was not reclaimed by vacuum. > > I cannot understand why there would be no advantage with more clients, > though... > > Alas, performance testing is quite sensitive to many details:-( > > The current status of the patch and recent mail thread discussion doesn't represent the same. Closed in 2016-11 commitfest with "returned with feedback" status. Please feel free to update the status once you submit the updated patch. Regards, Hari Babu Fujitsu Australia
