| From: | Rui DeSousa <rui(at)crazybean(dot)net> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Matteo Beccati <php(at)beccati(dot)com>, Thomas Munro <thomas(dot)munro(at)gmail(dot)com>, Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com>, Torsten Zuehlsdorff <mailinglists(at)toco-domains(dot)de>, Andres Freund <andres(at)anarazel(dot)de>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, Marko Tiikkaja <marko(at)joh(dot)to>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org>, Noah Misch <noah(at)leadboat(dot)com> |
| Subject: | Re: [HACKERS] kqueue |
| Date: | 2020-01-22 20:38:07 |
| Message-ID: | 38D69889-4F5D-440F-ADE9-ED0902F5D99C@crazybean.net |
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| Lists: | pgsql-hackers |
> On Jan 22, 2020, at 2:19 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> I cannot see any improvement on either FreeBSD 12 or NetBSD 8.1,
> either as to net TPS or as to CPU load. If anything, the TPS
> rate is a bit lower with the patch, though I'm not sure that
> that effect is above the noise level.
>
> It's certainly possible that to see any benefit you need stress
> levels above what I can manage on the small box I've got these
> OSes on. Still, it'd be nice if a performance patch could show
> some improved performance, before we take any portability risks
> for it.
>
Tom,
Here is two charts comparing a patched and unpatched system. These systems are very large and have just shy of thousand connections each with averages of 20 to 30 active queries concurrently running at times including hundreds if not thousand of queries hitting the database in rapid succession. The effect is the unpatched system generates a lot of system load just handling idle connections where as the patched version is not impacted by idle sessions or sessions that have already received data.
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