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Re: [PERFORM] scalability issues on win32

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Merlin Moncure <merlin(dot)moncure(at)rcsonline(dot)com>
Cc: Dave Page <dpage(at)vale-housing(dot)co(dot)uk>,pgsql-performance(at)postgresql(dot)org, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>,Magnus Hagander <mha(at)sollentuna(dot)net>,Win 32 hackers PGSQL <pgsql-hackers-win32(at)postgresql(dot)org>
Subject: Re: [PERFORM] scalability issues on win32
Date: 2004-12-02 19:28:17
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-hackers-win32pgsql-performance
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                        |
  pgman(at)candle(dot)pha(dot)pa(dot)us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

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