On Mon, Jul 13, 2015 at 12:06 PM, Haribabu Kommi <kommi.harib...@gmail.com> wrote: > On Thu, Jul 9, 2015 at 5:36 PM, Haribabu Kommi <kommi.harib...@gmail.com> > wrote: >> >> I will do some performance tests and send you the results. > > Here are the performance results tested on my machine. > > > Head vm patch vm+prefetch > patch > > First vacuum 120sec <1sec <1sec > second vacuum 180 sec 180 sec 30 sec > > I did some modifications in the code to skip the vacuum truncation by > the first vacuum command. > This way I collected the second vacuum time taken performance. > > I just combined your vm and prefetch patch into a single patch > vm+prefetch patch without a GUC. > I kept the prefetch as 32 and did the performance test. I chosen > prefetch based on the current > buffer access strategy, which is 32 for vacuum presently instead of an > user option. > Here I attached the modified patch with both vm+prefetch logic. > > I will do some tests on a machine with SSD and let you know the > results. Based on these results, > we can decide whether we need a GUC or not? based on the impact of > prefetch on ssd machines.
Following are the performance readings on a machine with SSD. I increased the pgbench scale factor to 1000 in the test instead of 500 to show a better performance numbers. Head vm patch vm+prefetch patch First vacuum 6.24 sec 2.91 sec 2.91 sec second vacuum 6.66 sec 6.66 sec 7.19 sec There is a small performance impact on SSD with prefetch. Regards, Hari Babu Fujitsu Australia -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers