[log4perl-devel] apache worker, mod_perl2, appender/semaphore problem under medium load

[<fo...@ne...>]

Hello,

I am running log4perl in a mod_perl2 script on an apache with worker
MPM.

Startig from 10 concurrent users, I am getting the following messages in
the error log.

[Fri Mar 20 10:37:28 2009] [error] [client 192.168.1.201] Couldn't set semaphore during object creation: Identifier removed at /usr/share/perl5/Log/Log4perl/Appender/Synchronized.pm line 45\n

More concurrent users means more of these errors.

The requests fail subsequently with http status 500.

Versions:
 - Kernel: 2.6.22-14-generic
 - Apache: 2.2.8 worker, self compiled
 - log4perl 1.10-1 (Ubuntu)

Configuration:
Apache:
	PerlRequire /apache/startup.pl
	PerlWarn 	On
	PerlTaintCheck	On

	Alias /action/ /apache/action/
	<Location /action/>
	      SetHandler perl-script
	      PerlResponseHandler ModPerl::Registry
	      PerlOptions +ParseHeaders
	      Options +ExecCGI
	      Order allow,deny
	      Allow from all 
	</Location>


Log4Perl:
	...
	my $conf = qq(
		log4perl.category		= $threshold, Syncer

	# File appender (unsynchronized)
		log4perl.appender.Logfile		= Log::Log4perl::Appender::File
		log4perl.appender.Logfile.autoflush	= 1
		log4perl.appender.Logfile.filename	= $filename
		log4perl.appender.Logfile.mode		= append
		log4perl.appender.Logfile.layout	= Log::Log4perl::Layout::PatternLayout
		log4perl.appender.Logfile.layout.ConversionPattern = %d{dd/MMM/yyyy:HH:mm:ss} %p %m%n

		# Synchronizing appender, using the file appender above
		log4perl.appender.Syncer		= Log::Log4perl::Appender::Synchronized
		log4perl.appender.Syncer.appender	= Logfile
		log4perl.appender.Syncer.destroy	= 1
	);

	Log::Log4perl::init( \$conf );
	my $logger = Log::Log4perl::get_logger();
	...


The threshold is set to INFO meaning that every call results in a single
log entry being made. The script runs for about one second.

When I tried out running the script as a handler (instead of the registry method), this did not
change the behaviour.

I understand that there are performance limits and eventually failures,
but is not that a bit early, with only ten concurrent usersr?

So I guess I have a misconfigured setup. Could anybody give me a good
hint? I googled for my error, but without luck.

Regs,

Christian Folini


-- 
I myself am human and free only to the extent that I acknowledge the
humanity and liberty of all my fellows... 
--- Mikhail Bakunin