The while loop is very slow. What am I doing wrong?

gistfile1.txt

#!/usr/bin/env perl

use Modern::Perl;
use BCV::DB;
use Search::Elasticsearch;
use JSON;

my $DB = BCV::DB->new($ENV{BOOTLOGDB}//'BCVcore');
my $e =  Search::Elasticsearch->new( nodes => 'bcvdb02:9200' );
my $index = 'crfbootlogdata';
my $idseq = 1;

my $query = q| select * from phone_boot_log_records |;

my $sth = $DB->prepare($query);
$sth->execute;
if ($e->indices->exists(index => $index)) {
    $e->indices->delete( index => $index );
    $e->indices->create( index => $index );
}

while (my $r = $sth->fetchrow_hashref) {
    $e->index(
        index => $index,
        type => 'broadsoft-bootlog',
        id => $idseq++,
        body => $r,
    );
    say encode_json($r);
}

$DB->disconnect;