Re: [HACKERS] log_destination=file

On Wed, Nov 15, 2017 at 12:33 AM, Robert Haas <robertmhaas@gmail.com> wrote:
> On Sun, Sep 10, 2017 at 5:29 AM, Dmitry Dolgov <9erthalion6@gmail.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