一个关于perl out of memory的问题

我写了一个导数据用的perl程序，运行的时候刚开始还可以，然后到了某一条数据突然就不再继续运行了，然后我查看内存占用情况，就会一直增长，一直耗光内存，然后提示out of memory
,如果是我的其中一个变量持续增长应该是改程序占用内存也是持续增长的，可是我观察内存占用情况，刚开始该程序一直维持在一个很低的情况，直到遇到某一条数据后，就开始一直增长了，请各位大侠们帮帮我，我死活找不出原因，我是perl新手，不太会debug。谢谢各位了。

下面是源代码，处于公司保密目的，我将其中的接口和数据库IP给替换成xxxxxx了，请各位多包涵！

#!/usr/bin/perl -w

use strict;

use warnings;

use DBI;

use XML::Smart;

use Data::Dumper;

use Encode qw/encode decode/;

use Digest::MD5 qw(md5 md5_hex md5_base64);

use MIME::Base64 qw(encode_base64 decode_base64);

use LWP::UserAgent;

require "db.pl";

my $dbh =  &get_joy_db;

#my $ii = 0;

#my $jj = 0;

my %db_joyid;



my %all_urls = ("电视剧"=>"http://xxxxx/get_list.php?channelid=58",

                                        "电影"=>"http://xxxxx/get_list.php?channelid=51",

                                        "播客"=>"http://xxxxx/get_video_list.php?channelid=1",

                                        "娱乐"=>"http://xxxxx/get_video_list.php?channelid=3");





while(my ($cat, $url) = each %all_urls){

        my @content_url = return_url_update($url);

        foreach my $u (@content_url) {

                print $cat,$u."\n";

                my $XML = XML::Smart->new( $u, 'XML::Smart::Parser' );

                my @items = reverse(@{ $XML->{root}{videolist}{video}});

                foreach my $item (@items) {

                        print "\n\n\n";

                        my $title = $dbh->quote(&encode("GBK",$item->{title}));

                        #print $title."\n";

                        my $id = &encode("GBK",$item->{id});

                        my $intro = $dbh->quote(&encode("GBK",$item->{desc}));

                        my $tags = $dbh->quote(&encode("GBK",$item->{tag}));

                        my $play_url = &encode("GBK",$item->{play_url});

                        my $src_image = &encode("GBK",$item->{img_url});

                        my $time = &encode("GBK",$item->{totaltime});

                        my $image = handleJoyPic($src_image,"joy");

                        $image = "http://cnimg.realnetworks.com.cn/guide/mdb/".$image;

                        my ($curdate,$curtime)=get_time();

                        print $cat."===>".$title."=>".$id."=>".$image."\n";

                        my $sql_chk = "select joyid from joy where joyid = $id";

                        my $sth_chk = &execsql($dbh, $sql_chk);

                        

                        while ( my ($joyid) = $sth_chk->fetchrow() ) {

                                $db_joyid{$joyid} = $joyid;

                        }

                        if ($db_joyid{$id}) {

                                print "\n\t"."数据库数据重复:".$title."\n";

                                #$jj++;

                        }else{

                                my $sql_insert = "insert into joy (`title`,`intro`,`tags`,`image_1`,`src_image`,`joyid`,`category`,`length`,`createdate`,`createtime`,`playurl`) values ($title,$intro,$tags,'$image','$src_image','$id','$cat','$time','$curdate','$curtime','$play_url');";

                                my $sth_insert = &execsql($dbh, $sql_insert);

                                print  "\n\t"."数据插入成功:".$title."\n";

                                $sth_insert->finish();

                                #$ii++;

                        }

                        $sth_chk->finish();

                        undef %db_joyid;

                }

        }

}

#print "总共插入$ii条数据，另有$jj条数据重复！";



sub get_time {

        my ($sec,$min,$hour,$day,$mon,$year)=localtime(time);

        $sec  = ($sec < 10)?"0$sec":$sec;

        $min  = ($min < 10)?"0$min":$min;

        $hour = ($hour < 10)?"0$hour":$hour;

        $day  = ($day < 10)?"0$day":$day;

        $mon  = ($mon < 9)?"0".($mon+1):($mon+1);

        $year += 1900;

        return "$year-$mon-$day", "$hour:$min:$sec";

}



sub get_joy_db {

    my ( $db_host, $db_name, $db_user, $db_pwd, $db_port, $db_timeout ) =

      ( "xxxxxxxxxxxxxxx", "movie", "root", "xxxxxxxxx", 9002, 0 );

    my $dbh =

      &db_open( $db_host, $db_name, $db_user, $db_pwd, $db_port, $db_timeout );

    return $dbh;

}



sub file_name {

    my ($filepath) = @_;

    my $pos = rindex( $filepath, "/" );

    if ( $pos == -1 ) {

        return $filepath;

    }

    else {

        return substr( $filepath, $pos + 1 );

    }

}



sub md5_filename{

        my ($filename) = @_;

        #print $filename;

        my $pos = rindex($filename,".");

        #print $pos."\n";

        my $prename = substr($filename,0,$pos);

        my $extname = substr($filename,$pos+1);

        return md5_hex($prename).".".$extname;

}



sub handleJoyPic {

    my ($arg,$partner) = @_;

    if ( $arg !~ /http:\/\/.*/isg ) {

        return "";

    }

    my $img_filename = file_name($arg);

        my $md5_filename = md5_filename($img_filename);

    my $hash         = md5_hex($arg);

    my $len          = length($hash);

    my $ascii        = 0;

    for ( my $i = 0 ; $i < $len ; $i++ ) {

        $ascii += ord( substr( $hash, $i, 1 ) );

    }

    my $path = sprintf( "%d/%d", $ascii % 128, $ascii % 53 );

    my $fixed_img_path = "$partner/$path/$md5_filename";

    my $cmd = "mkdir -p  $partner/$path/;wget $arg;mv $img_filename $partner/$path/$md5_filename";

    $cmd .=";/usr/local/bin/rsync -vtp --timeout=120 -R $fixed_img_path xxxxxxxxx::img_mdb";

    #print $cmd."\n";

    system("$cmd");

    #print $fixed_img_path."\n";

    return $fixed_img_path;

}



sub return_url_update{

        my ($url,$num) = @_;

        if (!$num) {

                $num = 50;

        }

        $url = $url."&start=0&num=".$num;

        return $url;

}