Re: [pgsql-hackers-win32] scalability issues on win32

Merlin Moncure wrote:
> > > This was an intersting Win32/linux comparison. I expected
> > > Linux to scale better, but I was surprised how poorly XP
> > > scaled.  It reinforces our perception that Win32 is for low
> > > traffic servers.
> >
> > That's a bit harsh given the lack of any further investigation so far
> > isn't it? Win32 can run perfectly well with other DBMSs with hundreds
> of
> > users.
> >
> > Any chance you can profile your test runs Merlin?
> >
>
> Ok, I am starting to strongly suspect the statistics collector of
> various kinds of malfeasance.  Right now I am running with the stats
> collector off and I am getting much better scalability and much more
> deterministic query times...that is, even when under moderate to heavy
> load query running times are proportional to the number of users on the
> system...the system is purring like a kitten right now with over a 100
> users logged in.
>
> This coupled with the fact that I was getting random restarts with the
> collector process makes me think that there is some kind of issue with
> the ipc between the collector and the backends that is blocking and/or
> is being improperly handled after failure.
>
> I was running with statement level stats on under scenarios with
> extremely high levels of query activity where the server might be
> processing 500-1500 queries/second or more spread out over multiple
> backends.
>
> I'll look into this issue more over next several days.  I'll dip back
> into the code and see if I can come up with a better
> answer...unfortunately I can't run the stats collector on until I can
> schedule another load test.

OK, the big problem is that we are nearing RC1.  We would like some
feedback on this as soon as possible.  A major Win32 cleanup for this
could delay the 8.0 release.

--
  Bruce Momjian                        |  http://candle.pha.pa.us
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