On Tue, May 26, 2015 at 12:10 AM, Andres Freund <and...@anarazel.de> wrote: > > On 2015-05-20 19:56:39 +0530, Amit Kapila wrote: > > I have done some tests with this patch to see the benefit with > > and it seems to me this patch helps in reducing the contention > > around ProcArrayLock, though the increase in TPS (in tpc-b tests > > is around 2~4%) is not very high. > > > > pgbench (TPC-B test) > > ./pgbench -c 64 -j 64 -T 1200 -M prepared postgres > > Hm, so it's a read mostly test.
Write not *Read* mostly. > I probably not that badly contended on > the snapshot acquisition itself. I'd guess a 80/20 read/write mix or so > would be more interesting for the cases where we hit this really bad. > Yes 80/20 read/write mix will be good test to test this patch and I think such a load is used by many applications (Such a load is quite common in telecom especially their billing related applications) and currently we don't have such a test handy to measure performance. On a side note, I think it would be good if we can add such a test to pgbench or may be use some test which adheres to TPC-C specification. Infact, I remember [1] people posting test results with such a workload showing ProcArrayLock as contention. [1] - http://www.postgresql.org/message-id/e8870a2f6a4b1045b1c292b77eab207c77069...@szxema501-mbx.china.huawei.com With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com
