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List:       apache-modperl
Subject:    Re: Even more on the register_cleanup bug
From:       Oleg Bartunov <oleg () sai ! msu ! su>
Date:       1999-06-30 17:22:16
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Ooh, 

I was to quick :-( My problem  is still alive
I tested wrong URL which worked fine before.

	Regards,

			Oleg

On Wed, 30 Jun 1999, Oleg Bartunov wrote:

> Date: Wed, 30 Jun 1999 20:06:08 +0400 (MSD)
> From: Oleg Bartunov <oleg@sai.msu.su>
> To: Chip Turner <chip@zfx.com>
> Cc: modperl <modperl@apache.org>, dougm@perl.apache.org, E.Mergl@bawue.de
> Subject: Re: Even more on the register_cleanup bug
> 
> Whoa,
> 
> it seems this patch is a good medicine  for my problem.
> I didn't test it very much but now ApacheDBI works fine !
> It's strange a bit that it worked on FreeBSD without this patch.
> 
> 	Regards,
> 		Oleg
> 
> On Wed, 30 Jun 1999, Chip Turner wrote:
> 
> > Date: Wed, 30 Jun 1999 15:38:20 +0000
> > From: Chip Turner <chip@zfx.com>
> > To: modperl <modperl@apache.org>
> > Cc: dougm@perl.apache.org
> > Subject: Even more on the register_cleanup bug
> > 
> > 
> > I've been narrowing down the bug I've posted about before, and though
> > I've not been able to reproduce it on a clean box, I've seen it happen
> > on at least two different boxes here where I work.  A patch is included
> > that fixed the problem here.
> > 
> > I've done some more testing, and here's what I can confirm:
> > 
> > PerlCleanupHandler behaves correctly
> > PerlLoggingHandler behaves correctly
> > Apache->request->register_cleanup does NOT behave correctly
> > 
> > Here's a snippet of code:
> > sub handler {
> >   my $r = shift;
> >   return Apache::Constants::DECLINED unless
> >     ($r->content_type() eq 'text/parthenon' or $r->content_type() eq
> > 'text/html');
> > 
> > #  Apache->request->register_cleanup(sub { warn "Apache/mod_perl cleanup
> > 1" });
> > 
> >   $r->register_cleanup(sub { warn "Apache/mod_perl true cleanup, pid $$"
> > });
> >   $r->push_handlers( PerlLogHandler => sub { warn "Apache/mod_perl
> > logging cleanup, pid $$" });
> > 
> > This code registers two cleanups that report to the error log.  Also,
> > there is a function:
> > sub handler {
> >   warn "Apache/mod_perl conf cleanup, pid $$";
> > }
> > 
> > In the appropriate package that is initialized like:
> > PerlCleanupHandler Parthenon::Apache::cleanup
> > 
> > Watching the error logs and running ab results in the following.
> > 
> > Before ab:
> > 
> > Conf:     768
> > Internal:     338
> > Logging:    1515
> > 
> > Then after 'ab -n 100 -c 5 http://(site)/' is executed, we get:
> > 
> > Conf:     872
> > Internal:     348
> > Logging:    1619
> > 
> > 
> > These numbers come from the following command:
> > echo -n "Conf: "; grep "conf cleanup" /etc/httpd/logs/(site).error |
> > grep pid | wc -l; 
> > echo -n "Internal: "; grep "true cleanup" /etc/httpd/logs/(site).error |
> > grep pid | wc -l; 
> > echo -n "Logging: "; grep "logging cleanup" /etc/httpd/logs/(site).error
> > | grep pid | wc -l
> > 
> > As we see, PerlConfHandler and PerlLogHandler both report 104 cleanups
> > for 100 requests (the extra 4 are from ab; it seems to actually initiate
> > 104 requests with c set to 5.  I've seen it request 109 when c is 10). 
> > But we see only 10 calls to the cleanup made by register_cleanup!  This
> > is on a clean restart of the server no less.  The problem is definitely
> > being exacerbated somehow by what the site is calculating (since my last
> > report, a number of actions have been added to that page).
> > 
> > After applying the patch below, all three numbers changed by the same
> > amount, 104.  Apparently, by the time mod_perl_cleanup_handler in
> > mod_perl.c gets called, the global mp_request_req doesn't point to the
> > same value that it did when the cleanup was initally requested.  That's
> > my theory, anyway.  This patch fixes the problem:
> > 
> > alpha:chip:src> diff -Naur mod_perl-1.20/src/modules/perl/mod_perl.c 
> > mod_perl-1.20-patched/src/modules/perl/mod_perl.c 
> > --- mod_perl-1.20/src/modules/perl/mod_perl.c   Thu Jun 10 22:19:55 1999
> > +++ mod_perl-1.20-patched/src/modules/perl/mod_perl.c   Wed Jun 30
> > 11:31:44 1999
> > @@ -1068,7 +1068,7 @@
> >  
> >  void mod_perl_cleanup_handler(void *data)
> >  {
> > -    request_rec *r = perl_request_rec(NULL);
> > +    request_rec *r = data; // perl_request_rec(NULL);
> >      SV *cv;
> >      I32 i;
> >      dPPDIR;
> > 
> > I don't know if this should be a permanent fix or if there is a better
> > solution, but it seems to be working here on-site.  Hope this is useful.
> > 
> > (CC'd to Doug as a 'formal' patch/report)
> > 
> > Chip
> > 
> > -- 
> > Chip Turner                   chip@ZFx.com
> >                               Programmer, ZFx, Inc.  www.zfx.com
> >                               PGP key available at wwwkeys.us.pgp.net
> > 
> 
> _____________________________________________________________
> Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
> Sternberg Astronomical Institute, Moscow University (Russia)
> Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
> phone: +007(095)939-16-83, +007(095)939-23-83
> 
> 
> 

_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83

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