I need to optimize performance for script that supposed to scan filesystem and collect info on *.msg files.

I made a script recursive but I'm not sure that this is the best way for implementation.

Additionally I look for top boxes with sort on hash keys

The directory structure is /test_vol/0/00/34567@test.com/1_sdr/34567.msg where range is 0-9 and 00-99 and number of mail accounts is huge

The code is: 

sub ScanDirectory {
    my ($workdir) = @_;

    my($startdir) = &cwd; # keep track of where we began

    chdir($workdir) or die "Unable to enter dir $workdir: $!\n";
    
    opendir(DIR, ".") or die "Unable to open $workdir: $!\n";
        my @names = readdir(DIR);
    closedir(DIR);

    foreach my $name (@names){

        next if ($name eq ".");
        next if ($name eq "..");
        next if ($name =~ /\.dat$|\.mdb^|\.snapshot/);

        if ( -d $name ) {
            if ($name =~ /^\d+\@\w/ ) {
                $all_mailbox_count++;
                $box_size=0;
            }

            &ScanDirectory($name);
            next;
        }

        if ( $name =~ /\.msg$/ ) {
            my $msg_size=(stat($name))[7];
            if ( $msg_size < 4096 ) {
            $box_size+=4096;
            } else {
                $box_size+=$msg_size;
            }
        }
    }

       if ( $workdir =~ /(\d+)\@/ ) {
            $msisdn=$1;
            $all_mailbox_size+=$box_size;
            if ( $box_size == 0 ) {
                $empty_mailbox++;
            } else {
                &top_size_mailbox($msisdn,$box_size);
            }
        }

        chdir($startdir) or die "Unable to change to dir $startdir: $!
+\n";
}


sub top_size_mailbox {

        my ($msisdn,$box_size)=@_;

        if ( keys( %top_size_mailbox ) < $num_top_size_box ) {
                $top_size_mailbox{$box_size}=$msisdn;
        } else {
                my $min=(sort {$a <=> $b} keys %top_size_mailbox)[0];
                if ( $box_size > $min ) {
                    delete $top_size_mailbox{$min};
                    $top_size_mailbox{$box_size}=$msisdn;
                }
        }

}

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In reply to Optimizing performance for script to traverse on filesystem by gdanenb

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