多次调用perl 连接数据库 内存不断累积直至耗尽

#!/usr/bin/perl
use DBI;
use strict;
use vars qw($dbh $sth);
my $jieguo = 0;

$dbh = DBI->connect("dbi:Oracle:host=192.168.1.22;sid=wddb", "lb_test", "lb_test");
my $sth = $dbh->prepare("BEGIN p_zhuli(?,?,?); END;");
$sth->bind_param(1, 'fenlei');
$sth->bind_param(2, 'zhuli');
$sth->bind_param_inout(3, \$jieguo,2);
$sth->execute();

$sth->finish();
dbh->disconnect();

我也遇到这个问题，内存释放不掉，不知道为什么