I'm running into problems using Class::DBI with threads. My setup is very simple: first use Class::DBI to retrieve a set of objects from database, then for each such object, I'll start a new thread to process it. The following is a stripped-down version (just retrieve one object, and start one thread): 
use strict;

package MyClass;
use base 'Class::DBI';

__PACKAGE__->set_db('Main','dbi:mysql:test', 'test','test');
__PACKAGE__->table('MYCLASS');
__PACKAGE__->columns(Primary=>qw/ID/);
__PACKAGE__->columns(Others => qw/NAME/);


package main;
use threads;

my $s = MyClass->retrieve(1);
threads->new(\&test, $s)->join();

print "done\n";
exit 0;

sub test{
    my $o = shift;
    print $o->name,"\n";
}

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I got the following errors: 
thread failed to start: DBD::mysql::db FETCH failed: handle 2 is owned
+ by thread 22432c not current thread 1b1e014(handles can't be shared 
+between threads and your driver may need a CLONE method added) at C:/
+Perl/site/lib/Ima/DBI.pm line 316.

Attempt to free non-existent shared string 'test~~test~~test~~AutoComm
+it~~ChopBlanks~~FetchHashKeyName~~PrintError~~RaiseError~~RootClass~~
+ShowErrorStatement~~Taint~~Username~~dbi_connect_method~~1~~1~~NAME_l
+c~~0~~1~~DBIx::ContextualFetch~~1~~1~~test~~connect_cached' during gl
+obal destruction.
Free to wrong pool 1b24430 not 222770 during global destruction.

[download]
The first error is instructive, but I'm not sure how to fix it, can one pass the objects retrieved via Class::DBI to other threads? by the way, line 316 of DBI.pm is the "unless" line in the following: 
sub _mk_db_closure {
    my ($class, @connection) = @_;
    my $dbh;
    return sub {
        unless ($dbh && $dbh->FETCH('Active') && $dbh->ping) {
            $dbh = DBI->connect_cached(@connection);
        }
        return $dbh;
    };
}

[download]
I'm more at a loss to the second one, it seems to be some db connection string, but who's doing the destruction and garbage collection here? Thanks.

In reply to threading problem with Class::DBI by johnnywang

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