code updated and tested 

#!/usr/bin/perl

use warnings;
use strict;
$|++;

use JSON;

my $l;
my @vals;
my $json;
my %pairs;

while (<>) {
    $l = $_;
    chomp $l;
    @vals = split /;/, $l;
    if ($vals[0] =~ /Query/) {
        $pairs{$vals[1]}{$vals[2]} = $vals[3];
    } elsif ($vals[0] =~ /Answer/) {
        $pairs{$vals[1]}{$vals[2]} = $vals[3];
        $json = encode_json $pairs{$vals[1]};
        print $json."\n";
        delete $pairs{$vals[1]};
    }
}

[download]
[root@hadron ~]# ./t-1207429.pl t-1207429.txt
{"ip":"1.2.3.4","host":"www.example.com"}
{"ip":"2.3.4.5","host":"www.cnn.com"}
{"ip":"3.4.5.6","host":"www.google.com"}

[download]

The real question is whether, if running this against 100GB file with >500000 hash entries, will delete actually reduce the size of the has or not?

Or is there a leaner way to do this?

In reply to Re: Memory utilization and hashes by bfdi533
in thread Memory utilization and hashes by bfdi533

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