Re: [mux@FreeBSD.org: Re: Anyone interested in improving postgresql scaling?]

Kris Kennaway <kris(at)obsecurity(dot)org> writes:
>>>>> I think the high number of setproctitle() calls are more problematic
>>>>> to us at the moment, Kris can comment on that.

> Since we've basically had it handed to us that calling setproctitle()
> thousands of times per second is something that real applications now
> do, we're pretty much forced to work on making it cheaper.
> ...
> However this won't help all the existing systems out there (including
> other affected OSes), so it would be great if you guys could meet us
> half way and find a way to make postgresql rate-limit these calls by
> default to some suitable compromise rate, like once/second or
> whatever.

Well, the thing is, we've pretty much had it handed to us that
current-command indicators that aren't up to date are not very useful.
So rate-limited updates strike me as a useless compromise. We have
the "real" solution (status advertised in PG's shared memory) already,
so the question in my mind is just how fast DBAs will wish to transition
to looking at "select * from pg_stat_activity" instead of looking at
"ps auxww".

I don't see anything wrong at all with making update_process_title
default to "off" in BSD-specific packaging of Postgres. It's a harder
sell to turn it off by default everywhere, because of all them Linux
users for whom that's just taking away a convenient status viewing
method. I think we might get there eventually, but we need a decent
interval to wean people away from the old method.

[ Disclaimer: I work for Red Hat, so am unlikely to favor doing anything
that is a loss on Linux. But I do use and like other platforms too;
just don't happen to have any BSD in-house currently, unless you're
willing to count Darwin as BSD. ]

regards, tom lane