Re: [HACKERS] WIP: Separate log file for extension

Antonin Houska <ah(at)cybertec(dot)at> writes:
> After having read the thread on your patch I think that the reason you were
> asked to evaluate performance was that your patch can possibly make syslogger
> a bottleneck. In contrast, my patch does not prevent user from disabling the
> syslogger if it (the syslogger) seems to cause performance issues.

Just to clarify that: we know that in workloads that emit lots of log
output, the log collector *already is* a bottleneck; there are reports
that some people can't use it because it's too slow. See e.g. towards
the end of this thread:

https://www.postgresql.org/message-id/flat/CABUevExztL0GORyWM9S4tR_Ft3FmJbRaxQdxj%2BBQZjpvmRurdw%40mail.gmail.com

and particularly the referenced thread from 2011. (I seem to recall other
reports but didn't have much luck finding them.)

I'm quite concerned by the proposed patch, and not even so much any
performance issues; what bothers me is that it adds complexity into a
portion of the system where we can ill afford it. Bugs in the logging
mechanism compromise one's ability to have any faith in tracking down
other bugs. The difficulty of reconfiguring the logger on the fly
is another reason to not want more configuration options for it.
On the whole, therefore, I'd just as soon not go there --- especially
seeing that there's been little field demand for such features.

regards, tom lane