use strict;
use DBI;

my $DB_HOST = "127.0.0.1";
my $DB_PORT = "3306";
my $DB_USER = "root";
my $DB_PASSWD = "";
my $DB_NAME = "test";

my $DB_DSN = "DBI:mysql:$DB_NAME:$DB_HOST:$DB_PORT";
my $dbh = DBI->connect($DB_DSN, $DB_USER, $DB_PASSWD, {PrintError => 1, RaiseError => 0, AutoCommit => 1});

my $abfrage = 'SELECT * FROM cluster;';
my $sth = $dbh->prepare($abfrage); 
$sth->execute();
my $ergebnis = $dbh->selectall_arrayref($sth);
$sth->finish();
		
$dbh->disconnect();

undef @{$ergebnis};
undef $ergebnis;

### hier ist die speicherbelegung immer noch voll

sleep(30);
exit;

### nach beenden des scripts die der speicher leer