my $dbh = DBI->connect("dbi:ODBC:testDSN", undef, undef);
    		
$dbh->{LongReadLen} = 65000;
$dbh->{LongTruncOk} = 0;

my $sql = "select * from $table_name";
my $table_records = $dbh->selectall_arrayref($sql) or die "cannot do " . $sql;

#...

$dbh->disconnect;