in reply to Fast seeking in a large array of hashes to generate a report.

Perhaps you could change the way you build your Dataobject. Instead of one array of hashes, you could build four hashes of (arrays of) hashes, each with a different field as the key. So, you could for example build a HoAoH with surname as key:

%Persons_by_surname = ( 'Schwartz' => [ { ..person 1 }, { ..person 2}, ], 'Wall' => [ {..person 1..} ] );

And the same for the other fields (except perhaps for age, where there will be a limited number of discrete values). Instead of looping over an array, this changes your algorithm to a hash lookup, which should be faster.

To facilitate your later lookup phase, you could put these data hashes in a wrapper hash like this:

my %data= ( 'surname' => \%Persons_by_surname, 'firstname' => \%Persons_by_firstname, # ... and so on );

Doing this, you'll have an initial hit on performance when building the extra hashes, but you should have faster lookups in the end. You'll have to benchmark your scripts to see whether this is worth it.