Forum Programmation.perl thread et mysql

J'ai un petit code qui sur le papier devrait bien marcher mais seulement quand je le lance ben ça marche nettement moins bien


use threads;
use strict;
use DBI;
use warnings;
use diagnostics;

my @pth;
my $ptiming;
my $rep;
my $database = "...";
my $hostname = "localhost";
my $login = "root";
my $mdp = "";
my $dsn = "DBI:mysql:$database:$hostname";
my $sth;
my $dbh;

threads->new(\&main)->join;

sub main
{
while(1)
{
$dbh = DBI->connect($dsn,$login,$mdp) or die "ECHEC connexion";
@pth = ();
for(my $i=0;$i
{
$pth[$i] = threads->new(\&subroutine);
}
$ptiming = threads->new(\&timing);
$ptiming->join;
for(my $j=0;$j
{
$rep = $pth[$j]->join;
$sth = $dbh->prepare("INSERT INTO test VALUES('test')");
$sth->execute();
}
$dbh->disconnect
}
}

sub subroutine
{
return "oO";
}

sub timing
{
sleep(0);
}

Donc le premier tour de boucle se passe bien mais après, un warning sur le premier insert du 2eme tour et sur le 2 insert perl plante :

Use of uninitialized value in null operation during global destruction (#1)
(W uninitialized) An undefined value was used as if it were already
defined. It was interpreted as a "" or a 0, but maybe it was a mistake.
To suppress this warning assign a defined value to your variables.

To help you figure out what was undefined, perl tells you what operation
you used the undefined value in. Note, however, that perl optimizes your
program and the operation displayed in the warning may not necessarily
appear literally in your program. For example, "that $foo" is
usually optimized into "that " . $foo, and the warning will refer to
the concatenation (.) operator, even though there is no . in your
program.

Use of uninitialized value in null operation during global destruction (#1)
(W uninitialized) An undefined value was used as if it were already
defined. It was interpreted as a "" or a 0, but maybe it was a mistake.
To suppress this warning assign a defined value to your variables.

To help you figure out what was undefined, perl tells you what operation
you used the undefined value in. Note, however, that perl optimizes your
program and the operation displayed in the warning may not necessarily
appear literally in your program. For example, "that $foo" is
usually optimized into "that " . $foo, and the warning will refer to
the concatenation (.) operator, even though there is no . in your
program.

Argument "NAME" isn't numeric in null operation during global destruction (#2)
(W numeric) The indicated string was fed as an argument to an operator
that expected a numeric value instead. If you're fortunate the message
will identify which operator was so unfortunate.

Ca c'est tout le blabla auquel j'ai droit mais qui ne m'avance pas plus que ça ...Si quelqu'un avait une idée !?