Re: mod_perl2 + fork + DBI = Chaos

Ok, then maybe I need to supply some code here to try and get clarification:

mailfile.pl
###########
use strict;
...
use POSIX;

#gather needed modules and objects
my $fileOBJ = new MyOBJS::FILE($in->param('id'));
my $clientOBJ = new ...
my $userOBJ = new ...
# All OBJjects have a {DBH} property which is their DB handle
# I hear I have to disconnect these first, do I have to disconnect ALL?
$fileOBJ->{DBH}->disconnect;
$SIG{CHLD} = 'IGNORE';
my $pid;
if ($pid = fork) {
	warn "Pid = $pid";
} elsif (defined $pid) {
	close(STDOUT);
	close(STDIN);
	close(STDERR);

	# chdir to /, stops the process from preventing an unmount
	chdir '/' or die "Can't chdir to /: $!";
	# dump our STDIN and STDOUT handles
	open STDIN, '/dev/null' or die "Can't read /dev/null: $!";
	open STDOUT, '>/dev/null' or die "Can't write to /dev/null: $!";
	# redirect for logging
	open STDERR, '>/tmp/stderr' or die "Can't write to /tmp/stderr: $!";
	# Prevent locking to apache process
	setsid or die "Can't start a new session: $!";

	# Create file download link email
	my $mailSTR = ...

	# Send the mail possibly to many people
	foreach my $person (@people) {
		open(MAIL, '|' . &cfg('sendmail_location') . ' -t');
		print MAIL $mailSTR;
		close(MAIL);
	}

	# Need to recreate the DBI connection on the $fileOBJ I hear
	$fileOBJ = new MyOBJS::FILE($in->param('id'));

	# Do some SQL to update the $fileOBJ status based on mailout
	$fileOBJ->sql....

	# create LOGGING Objects to log stuff
	my $logOBJ = new ...
	$logOBJ->sql...

	CORE::exit(0);
}

print $in->redirect... # For the parent to redirect the browser

# Done.

Is there a glaring mistake in the above?

The parent does no more DB stuff, it just sends a redirect.

This runs under ModPerl::Registry.

I'd like to get at least one thing working tonight, either the forking 
or the DBI, I'll be happy!

Tosh



Perrin Harkins wrote:
> On Mon, Jan 25, 2010 at 3:48 PM, Tosh Cooey <[email protected]> wrote:
>> Thanks Perrin, the forking, my child got a PID of 30033 and then afterwards
>> when I checked the processes (ps) for 30033 I see:
>>
>> [apache2] <defunct>
>>
>> Is that what's supposed to happen?
> 
> After you call exit?  No.  It should be gone.  That's a zombie process.
> 
>> That PM thread seems to indicate that I must disconnect every DBH, not just
>> the ones that I will use.
> 
> Either that, or you need to set InactiveDestroy on all of them in the
> child process.  Otherwise, when the child exits, it messes up all of
> them for the parent.
> 
>> Are you also suggesting the use of
>> Parallel::ForkManager for forks?
> 
> No.  The DBI stuff is the same with either.
> 
> - Perrin
> 

-- 
McIntosh Cooey - Twelve Hundred Group LLC - http://www.1200group.com/