Re: [HACKERS] log_destination=file

On Wed, Nov 15, 2017 at 12:33 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Sun, Sep 10, 2017 at 5:29 AM, Dmitry Dolgov <9erthalion6(at)gmail(dot)com> wrote:
>> average latency:
>>
>> clients patch master
>> 10 0.321 0.286
>> 20 0.669 0.602
>> 30 1.016 0.942
>> 40 1.358 1.280
>> 50 1.727 1.637
>
> That's still a noticeable slowdown, though. And we've had previous
> reports of the overhead of logging being significant as well:
>
> http://postgr.es/m/CACLsApsA7U0GCFpojVQem6SGTEkv8vnwdBfhVi+dqO+gu5gdCA@mail.gmail.com
>
> I seem to recall a discussion, perhaps in-person, around the time Theo
> submitted that patch where it was reported that the logging collector
> could not be used on some systems he was working with because it
> became a major performance bottleneck. With each backend writing its
> own messages to a file, it was tolerable, but when you tried to funnel
> everything through a single process, the back-pressure slowed down the
> entire system unacceptably.

I have moved this patch to next CF for now.. The original patch still applies.
--
Michael