There is a problem here:

my $dbh = DBI->connect("dbi:Oracle:$dbname", $user, $passwd,
        {
            AutoCommit => 0,
            RaiseError => 1,
            RowCacheSize => 10000,
            ora_array_chunk_size => 100000,
            #ora_check_sql => 0,
            #ora_verbose => 0xff,
            #ora_oci_success_warn => 1,
        }
);
[download]

To my understanding, AutoCommit => 0; doesn't mean much. The default action will be to "commit" each insert operation no matter what this says, if you do not start a transaction explicitly.

You need to start a transaction explicitly, insert huge amount of rows and then end the transaction explicitly. As I have suggested before, about 128K rows per commit will work fine.