If the number of keys is the cause of the memory cunsumption, make the keys smaller and more efficient. It might matter if you are low on memory. Best reason to pack the IP's is the it is much easier to sort

use List::Util  qw( shuffle    );
use Devel::Size qw( total_size );

my ($x, %ip0, %ip1, %ip2, %ip3, %ip4, %ip5) = 31;

foreach my $i0 ((shuffle 1..254)[0..$x]) {
foreach my $i1 ((shuffle 1..254)[0..$x]) {
foreach my $i2 ((shuffle 1..254)[0..$x]) {
foreach my $i3 ((shuffle 1..254)[0..$x]) {
    $ip0{"$i0.$i1.$i2.$i3"}++;
    $ip1{"$i0.$i1"}{"$i2.$i3"}++;
    $ip2{$i0}{$i1}{$i2}{$i3}++;
    $ip3{pack "CCCC", $i0, $i1, $i2, $i3}++;
    $ip4{pack "CC", $i0, $i1}{pack "CC", $i2, $i3}++;
    $ip5{pack "C", $i0}{pack "C", $i1}{pack "C", $i2}{pack "C", $i3}++
+;
    }}}}

printf "{192.168.101.208}    : %9d\n", total_size (\%ip0);
printf "{192.168}{101.208}   : %9d\n", total_size (\%ip1);
printf "{192}{168}{101}{208} : %9d\n", total_size (\%ip2);
printf "{xC0xA8x65xD0}       : %9d\n", total_size (\%ip3);
printf "{xC0xA8}{x65xD0}     : %9d\n", total_size (\%ip4);
printf "{xC0}{xA8}{x65}{xD0} : %9d\n", total_size (\%ip5);


==>

{192.168.101.208}    : 116483356
{192.168}{101.208}   :  69879492
{192}{168}{101}{208} :  71176834
{xC0xA8x65xD0}       : 106954864
{xC0xA8}{x65xD0}     :  69611776
{xC0}{xA8}{x65}{xD0} :  71176690

[download]

On my machine using perl-5.28.0, $ip4{pack "CC", $i0, $i1}{pack "CC", $i2, $i3} proves to be the most memory-friendly approach


Enjoy, Have FUN! H.Merijn

In reply to Re^2: Hash Search is VERY slow by Tux
in thread Hash Search is VERY slow by rtjensen

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