#!/usr/bin/perl -w
use warnings; 
use strict;
use DBI;
use Data::Dumper;
use POSIX qw( strftime );

my $database = 'db_name';
my $db_user = 'user';
my $db_password = 'pwd';
my $db_hostname = 'db_hostname';

my $dbh2 = DBI->connect("DBI:mysql:database=$database:host=$db_hostname",$db_user,$db_password,
    { RaiseError => 1, AutoCommit => 1, mysql_auto_reconnect => 1 } # Added AutoCommit => 1, mysql_auto_reconnect => 1 while trying to make it work
);
die "unable to connect to server $DBI::errstr" unless $dbh2;

my $sql2_1 = q^
    INSERT INTO table_name (col_1, col_2, col_3, col_4, col_5)
    VALUES (?,?,?,?,?) ^;
my $sth2_1 = $dbh2->prepare($sql2_1);
my $grp=0; 
$dbh2->begin_work; 

while(my @row = $sth1->fetchrow_array){
    $grp++; 
    if ($grp>1000) {$dbh2->commit;$dbh2->begin_work; $grp=0;} 
    unless ($row[3]) {$row[3]=undef;} 
    $sth2_1->execute($row[0],$row[1],$row[2],$row[3],$row[4]); 
}
$dbh2->commit;
$sth1->finish();
$dbh2->disconnect();