Re: [RFC] Change the default of update_process_title to off

On Wed, Aug 24, 2016 at 2:35 PM, Tsunakawa, Takayuki
<tsunakawa(dot)takay(at)jp(dot)fujitsu(dot)com> wrote:
> From: Peter Geoghegan [mailto:pg(at)heroku(dot)com]
>> On Tue, Aug 23, 2016 at 1:44 PM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
>> >> [Windows]
>> >> #clients on off
>> >> 12 29793 38169
>> >> 24 31587 87237
>> >> 48 32588 83335
>> >> 96 34261 67668
>> >
>> > This ranges from a 28% to a 97% speed improvement on Windows! Those
>> > are not typos! This is a game-changer for use of Postgres on Windows
>> > for certain workloads!
>>
>> While I don't care all that much about performance on windows, it is a little
>> sad that it took this long to fix something so simple. Consider this exchange,
>> as a further example of our lack of concern here:
>>
>> https://www.postgresql.org/message-id/30619.1428157653@sss.pgh.pa.us
>
> Probably, the useful Windows Performance Toolkit, which is a counterpart of perf on Linux, was not available before. Maybe we can dig deeper into performance problems with it now.
>
> As a similar topic, I wonder whether the following still holds true, after many improvements on shared buffer lock contention.
>
> https://www.postgresql.org/docs/devel/static/runtime-config-resource.html
>
> "The useful range for shared_buffers on Windows systems is generally from 64MB to 512MB."

I don't use Windows, but I have heard recently that this is still true
from someone who was testing with pgbench. He reported a dip in the
curve above 512MB.

Another database vendor recommends granting SeLockMemoryPrivilege so
that it can use large pages on Windows when using several GB of buffer
pool. I wonder if that might help Postgres on Windows. This could be
useful as a starting point to test that theory:

https://www.postgresql.org/message-id/CAEepm%3D075-bgHi_VDt4SCAmt%2Bo_%2B1XaRap2zh7XwfZvT294oHA%40mail.gmail.com

--
Thomas Munro
http://www.enterprisedb.com