gistfile1.txt

use DBI;
use Data::Dumper;
my $dbh = DBI->connect('dbi:mysql:database=sandbox', 'sandbox', 'sandbox');

$dbh = $dbh->clone();

warn Dumper($dbh);

$dbh = $dbh->clone();

warn Dumper($dbh);

===============結果
$VAR1 = bless( {}, 'DBI::db' );
$VAR1 = bless( {}, 'DBI::db' );
================

なんだだけど、

==================
use DBI;
use Data::Dumper;
my $dbh = DBI->connect('dbi:mysql:database=sandbox', 'sandbox', 'sandbox');

$dbh = $dbh->clone({});

warn Dumper($dbh);

$dbh = $dbh->clone();

warn Dumper($dbh);

===============結果
$VAR1 = bless( {}, 'DBI::db' );
$VAR1 = undef;
==================
clone({})にするだけでこうなってしまうorz
DBI: 1.616