Re: Move PinBuffer and UnpinBuffer to atomics

On Fri, Mar 25, 2016 at 8:09 PM, Alexander Korotkov <a.korotkov@postgrespro.ru> wrote:

Could anybody run benchmarks?  Feature freeze is soon, but it would be *very nice* to fit it into 9.6 release cycle, because it greatly improves scalability on large machines.  Without this patch PostgreSQL 9.6 will be significantly behind competitors like MySQL 5.7.

I have run the performance and here are the results.. With latest patch I did not see any regression at lower client count (median of 3 reading).

scale factor 1000 shared buffer 8GB readonly

Client Base patch

1 12957 13068

2 24931 25816

4 46311 48767

32 300921 310062

64 387623 493843

128 249635 583513

scale factor 300 shared buffer 8GB readonly

Client Base patch

1 14537 14586    --> one thread number looks little less, generally I get ~18000 (will recheck).

2 34703 33929    --> may be run to run variance (once I get time, will recheck)

4 67744 69069

32 312575 336012

64 213312 539056

128 190139 380122

Summary:

Actually with 64 client we have seen ~470,000 TPS with head also, by revering commit 6150a1b0.

refer this thread: (http://www.postgresql.org/message-id/CAA4eK1+ZeB8PMwwktf+3bRS0Pt4Ux6Rs6Aom0uip8c6shJWmyg@mail.gmail.com)

I haven't tested this patch by reverting commit 6150a1b0, so not sure can this patch give even better performance ?

It also points to the case, what Andres has mentioned in this thread.

http://www.postgresql.org/message-id/20160226191158.3vidtk3ktcmhimdu@alap3.anarazel.de