"Free to wrong pool" error in Apache logs under high load - modperl

This is a discussion on "Free to wrong pool" error in Apache logs under high load - modperl ; Hi all, Apologies if this isn't the right forum, but I am not sure where to turn to... I have mod_perl 2.0.4 installed with ActivePerl 5.10.0 under Apache 2.2.9 running on Windows 2003 Server SP1. I have a very simple ...

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Thread: "Free to wrong pool" error in Apache logs under high load

  1. "Free to wrong pool" error in Apache logs under high load

    Hi all,

    Apologies if this isn't the right forum, but I am not sure where to turn
    to...

    I have mod_perl 2.0.4 installed with ActivePerl 5.10.0 under Apache 2.2.9
    running on Windows 2003 Server SP1.

    I have a very simple PerlResponseHandler hooked in via httpd.conf for a
    specific Location. My custom PerlResponseHandler simply prints back "Hello
    World" on the HTTP Response. E.g. (simplified obviously):

    sub handler {
    my $r = shift;
    my $s = $r->server;
    print "Hello World";
    return Apache2::Const::OK;
    }
    1;

    The PerlResponseHandler works fine for most requests, however if I blast a
    whole bunch of HTTP requests on multiple threads, etc to Apache, the Web
    server stops handling responses. Connections eventually time out with no
    response. Apache error.log shows the following:

    Free to wrong pool da2750 not 184a6a8.

    Which leads me to believe there is something funny going on with multiple
    threads, etc.

    Where do I start to dive in and figure this out? I don't think I am doing
    anything out of the ordinary - it is pretty basic stuff. I am concerned my
    version of mod_perl or ActivePerl has some issues around this...

    Any tips greatly appreciated!

    Thanks,
    Scott


  2. Re: "Free to wrong pool" error in Apache logs under high load

    Scott Tomilson wrote:
    > Hi all,
    >
    > Apologies if this isn't the right forum, but I am not sure where to turn
    > to...
    >
    > I have mod_perl 2.0.4 installed with ActivePerl 5.10.0 under Apache 2.2.9
    > running on Windows 2003 Server SP1.

    Well, that sounds like you are in the right forum anyway..

    >
    > I have a very simple PerlResponseHandler

    and that even more.. Welcome !

    hooked in via httpd.conf for a
    > specific Location. My custom PerlResponseHandler simply prints back "Hello
    > World" on the HTTP Response. E.g. (simplified obviously):
    >
    > sub handler {
    > my $r = shift;
    > my $s = $r->server;


    are you using that $s later ? seems useless otherwise

    > print "Hello World";


    my $count = $r->print "Hello World"; # ?
    I'm not sure it makes that much difference, but it would seem more
    consistent to use in this environment.
    http://perl.apache.org/docs/2.0/api/....html#C_print_

    > return Apache2::Const::OK;
    > }
    > 1;
    >
    > The PerlResponseHandler works fine for most requests, however if I blast a
    > whole bunch of HTTP requests on multiple threads, etc to Apache, the Web
    > server stops handling responses. Connections eventually time out with no
    > response. Apache error.log shows the following:
    >
    > Free to wrong pool da2750 not 184a6a8.
    >
    > Which leads me to believe there is something funny going on with multiple
    > threads, etc.
    >

    It definitely sounds that way, but that's way out of my league.
    (Might that extra $r->server have something to do with it ?)

    Perrin, Fred, Torsten ? help !


  3. Re: "Free to wrong pool" error in Apache logs under high load

    On Thu 09 Oct 2008, André Warnier wrote:
    > > The PerlResponseHandler works fine for most requests, however if I
    > > blast a whole bunch of HTTP requests on multiple threads, etc to
    > > Apache, the Web server stops handling responses. *Connections
    > > eventually time out with no response. *Apache error.log shows the
    > > following:
    > >
    > > Free to wrong pool da2750 not 184a6a8.
    > >
    > > Which leads me to believe there is something funny going on with
    > > multiple threads, etc.

    >
    > It definitely sounds that way, but that's way out of my league.
    > (Might that extra $r->server have something to do with it ?)
    >
    > Perrin, Fred, Torsten ? help !


    Sorry guys, I have read my name at least twice in similar mails lately.
    But I must say I am under heavy load with my daytime job and this will
    continue almost certainly till the end of the year. Plus my father had
    a heart attack a week ago. (3 bypasses but he will survive.) So, I am
    afraid, I am not going to be much help.

    Torsten

    --
    Need professional mod_perl support?
    Just hire me: torsten.foertsch@gmx.net


  4. Re: "Free to wrong pool" error in Apache logs under high load

    On Thu, Oct 9, 2008 at 3:07 AM, Scott Tomilson wrote:
    > Free to wrong pool da2750 not 184a6a8.
    >
    > Which leads me to believe there is something funny going on with multiple
    > threads, etc.


    In the past these have typically been threading problems. I don't run
    Windows or threads, so I'm probably not going to be much help to you
    on this, but if you're not using a build you got from perl.apache.org
    I would consider trying that first. Are you loading any other
    modules, or just running this one simple test?

    - Perrin


  5. Re: "Free to wrong pool" error in Apache logs under high load

    Thanks Perrin.

    I am running a build of mod_perl I got via perl.apache.org, yes (or I think
    probably linked to uwinnipeg?). No other modules than the standard ones,
    plus the standard ActivePerl download from ActiveState. We actually tried
    the same solution on Solaris and it worked fine. It does seem specific to
    Windows itself - or more likely ActivePerl on Windows...

    Cheers,
    Scott

    On Fri, Oct 10, 2008 at 12:03 AM, Perrin Harkins wrote:

    > On Thu, Oct 9, 2008 at 3:07 AM, Scott Tomilson
    > wrote:
    > > Free to wrong pool da2750 not 184a6a8.
    > >
    > > Which leads me to believe there is something funny going on with multiple
    > > threads, etc.

    >
    > In the past these have typically been threading problems. I don't run
    > Windows or threads, so I'm probably not going to be much help to you
    > on this, but if you're not using a build you got from perl.apache.org
    > I would consider trying that first. Are you loading any other
    > modules, or just running this one simple test?
    >
    > - Perrin
    >



  6. Re: "Free to wrong pool" error in Apache logs under high load

    On Fri 10 Oct 2008, Scott Tomilson wrote:
    > I am running a build of mod_perl I got via perl.apache.org, yes (or I
    > think probably linked to uwinnipeg?). *No other modules than the
    > standard ones, plus the standard ActivePerl download from
    > ActiveState. *We actually tried the same solution on Solaris and it
    > worked fine. *It does seem specific to Windows itself - or more
    > likely ActivePerl on Windows...


    The windows MPM is multithreaded, the prefork MPM that you have probably
    used on Solaris is not. That makes a difference.

    Torsten

    --
    Need professional mod_perl support?
    Just hire me: torsten.foertsch@gmx.net


  7. Re: "Free to wrong pool" error in Apache logs under high load

    Actually - we compiled Apache with MPM=worker on Solaris...

    Scott


    On Fri, Oct 10, 2008 at 4:54 PM, Torsten Foertsch
    wrote:

    > On Fri 10 Oct 2008, Scott Tomilson wrote:
    > > I am running a build of mod_perl I got via perl.apache.org, yes (or I
    > > think probably linked to uwinnipeg?). No other modules than the
    > > standard ones, plus the standard ActivePerl download from
    > > ActiveState. We actually tried the same solution on Solaris and it
    > > worked fine. It does seem specific to Windows itself - or more
    > > likely ActivePerl on Windows...

    >
    > The windows MPM is multithreaded, the prefork MPM that you have probably
    > used on Solaris is not. That makes a difference.
    >
    > Torsten
    >
    > --
    > Need professional mod_perl support?
    > Just hire me: torsten.foertsch@gmx.net
    >



  8. Re: "Free to wrong pool" error in Apache logs under high load

    Sorry - I mean MPM=worker (multi thread)

    Cheers,
    Scott

    On Fri, Oct 10, 2008 at 5:04 PM, Scott Tomilson wrote:

    > Actually - we compiled Apache with MPM=worker on Solaris...
    >
    > Scott
    >
    >
    >
    > On Fri, Oct 10, 2008 at 4:54 PM, Torsten Foertsch <
    > torsten.foertsch@gmx.net> wrote:
    >
    >> On Fri 10 Oct 2008, Scott Tomilson wrote:
    >> > I am running a build of mod_perl I got via perl.apache.org, yes (or I
    >> > think probably linked to uwinnipeg?). No other modules than the
    >> > standard ones, plus the standard ActivePerl download from
    >> > ActiveState. We actually tried the same solution on Solaris and it
    >> > worked fine. It does seem specific to Windows itself - or more
    >> > likely ActivePerl on Windows...

    >>
    >> The windows MPM is multithreaded, the prefork MPM that you have probably
    >> used on Solaris is not. That makes a difference.
    >>
    >> Torsten
    >>
    >> --
    >> Need professional mod_perl support?
    >> Just hire me: torsten.foertsch@gmx.net
    >>

    >
    >



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