I'm working with a complex data structure that looks like this: 
$data[1]->{'477'}->[5] = [ 'value', 'value', 0 , undef, 5, 'value' ];

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The code was working quite nicely until I started working with very large data sets that caused my machine to run out of memory. To get around this problem, I'm trying to use a disk-based tied data structure with MLDBM. Unfortunately, I can't get it to work. Here is some simplified code: 
use MLDBM qw(DB_File Storable);
# ... stuff ....
foreach $gid (@group_ids) {
    my %temp_hash;
    unlink "$DBFilePath/$$.$gid" if -e "$DBFilePath/$$.$gid";
    tie %temp_hash, 'MLDBM', "$DBFilePath/$$.$gid", O_RDWR|O_CREAT, 06
+40
            or die "Can't tie temp_array to $DBFilePath/$$.$gid: $!";
    $data[$gid] = \%temp_hash;

    foreach $sample_id (@{$groups[$gid]}) {
        foreach $element_num ( 0 .. $element_count ) {
            $element = [];
            # ... do a bunch of stuff here ...
            $data[$gid]->{$sample_id}->[$element_num] = $element;
        }
    }
}

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Unfortunately, that assignment at the end doesn't take, and $data[$id] remains empty. I've tried things like this: 
$tmp = $data[$gid]->{$sample_id};
$tmp->[$element_num] = $element;

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But that still doesn't work. The only way I've found to add anything to $data[$id] is to assign an array ref in its entirety: 
$tmp = $data[$gid];
$tmp=>{$sample_id} = [ $element1, $element2, ... ];

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That is obviously not a workable solution, since I need to add elements one by one to get around the memory issues. Am I asking for too much or am I just doing this wrong? Thanks!

In reply to Need help with complex tied data structure by genecutl

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