my %ds1_tables = (); 
my %ds2_tables = (); 

foreach my $key (keys %{$DS1{PERL}[0]{TABLES}}) {
  $ds1_tables{$key} = 1;
}

foreach my $key (keys %{$DS2{PERL}[0]{TABLES}}) {
  $ds2_tables{$key} = 1;
}

foreach my $key (keys %ds1_tables) {
  if (!exists $ds2_tables{$key}) {
    print "$key does not exist in table 2.\n";
  } else {
    print "$key exists in table 2.\n";
  }
}