In order to describe it more clearly , i have 1 example below, in which i have created 1 big hash-of-hash. Although i have put only 2 HOH inside %TV overhere ( just for clarity sake ), but in my code i have it 300 or more HOH ( while incrementing the key e.g jetsons1, jetsons2... ) in order to check the memory usage.

 #!/usr/bin/perl5.8
use Proc::ProcessTable;
#use Tie::File::AsHash;
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 my %hash= ();

%TV = (  flintstones =>{ series   => "flintstones",
                          nights   => [ qw(monday thursday friday) ],
                        members    => [ { name => "fred",    role => "
+lead", age  => 36, },
                                        { name => "wilma",   role => "
+wife", age  => 31, },
                                        { name => "pebbles", role => "
+kid",  age  =>  4, },
                                      ],
                       },
         jetsons1    => { series   => "jetsons",
                         nights   => [ qw(wednesday saturday) ],
                         members  => [ { name => "george",  role => "l
+ead", age  => 41, },
                                       { name => "jane",    role => "w
+ife", age  => 39, },
                                       { name => "elroy",   role => "k
+id",  age  =>  9, },
                                     ]
                       },
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 sub memory_use {
    my $t = new Proc::ProcessTable;
    foreach my $got ( @{$t->table} ) {
        next if not $got->pid eq $$;
        return $got->size;
    }
}
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  my $count = 10;
  my $key = 'test';

  #tie  %hash, 'Tie::File::AsHash', 'abc.csv', split => ':' or die "Pr
+oblem tying %hash: $!";

  foreach my $family (keys %TV) {
      $count++;
      my $record = "";
      my $rec = $TV{$family};
      my $key = $family . $rec->{series};

      for $person ( @{ $rec->{members} } ) {
          $record .= $person->{name}."," . $person->{role}. ","
                                         . $person->{age} . ","
                                         . $rec->{series}   . ","
                                         . $rec->{nights}[0];
      }

      print "\n Key:    $key \n";
      print "\n Record: $record \n";


      $hash{$key} = $record;

      if ( $count%10 == 0 ) {
          sleep(10 );
          print "\n Record counter => [$count] \n";
          print "\n Process Status:" . ( ( memory_use()/1024 )/1024 ) 
+."MB \n";
          %hash = (); # if we comment it memory constant
      }
  } #----for 1----#
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