This might be a little better. 

my $temp;
while (($entry,$temp) = each %my_hash) {
  foreach $timeStamp ( sort keys %$temp) {
    my @tskeys = sort keys %{$temp->{$timeStamp}};
    print $Hentry "$entry\t$timeStamp\t", scalar @tskeys;
    print $Hentry "\t$_\t", $my_hash{$entry}{$timeStamp}{$_} for @tske
+ys;
    print $Hentry "\n";
  }
}

[download]

What I've done here is factor out the repeated call to keys on %{$temp->{$timeStamp}} and turned the foreach my $id loop into the statement modifier form. The lack of a block might be faster.

In reply to Re: Optimizing Iterating over a giant hash by kyle
in thread Optimizing Iterating over a giant hash by oron

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