Dear monks,

My first post here and I am afraid my question might be so unwise that I look silly but here goes. The members of this monastery have seemed during my many lurking years as being benevolent and kind so maybe I will not be ordered to serve too harsh a penance...

Update - the memory problem occurs even if I copy the arrays contrary to my this post, as described at the end.

Anyway... I'm using Chart clicker to make quite a few graphs (of network stats). Im having an out of memory exception half way through my list of graphs and as far as I thought it should not happen. I am passing in references to arrays to the function which creates the chart objects and I thought when the function returned all associated variables which were created inside the function would be freed but it seems not. If I dereference and copy the array the out of memory problem does not occur. Anyway its probably better for me to show some code which reproduces the problem, as I am not old and wise enough to be able to talk that much more about what I expect to happen and what exactly I am doing. Perhaps there is a simple obvious 'unrelated to chart clicker' action I am taking which I have gotten away with for all these years I have been using perl, or perhaps theres a less obvious reason, but the code will I am sure speak for itself far clearer than I ever can. 
#!/usr/bin/perl -s -w

use Chart::Clicker;
use Chart::Clicker::Data::Series;
use Chart::Clicker::Data::DataSet;

$| = 1;

sub mysub {
    ($x, $y) = @_;

    my $chart = Chart::Clicker->new;

    my @x_copy = @$x;
    my @y_copy = @$y;
    
    my $series = Chart::Clicker::Data::Series->new(
        keys    =>      $x, # if I use \@x_copy and 
        values  =>      $y, # \@y_copy here instead, there is no probl
+em 
    );

     my $dataset = Chart::Clicker::Data::DataSet->new(
        series  =>      [ $series ],
    );

    $chart->add_to_datasets($dataset);

     $chart->write_output('test.png');
}
    
my @x_axis;
my %a_hash;

for (my $t=0;$t<200;$t++){
    $x_axis[$t] = $t*10;
    @{$a_hash{abc}}[$t] = int(rand(100));
}

    
for (my $x=0;$x<10000;$x++) {    
    &mysub(\@x_axis, \@{$a_hash{abc}});
    print ".";
}

[download]
As you can see in the comments if I use copied arrays there is no out of memory problem. If I return during the function anywhere before the $chart->write_output, there is no memory problem. But once $chart->write_output has been called, if I am using the original arrays (not local copies), I have an out of memory exception after few hundred graphs are created (in the above code it takes about 4000 graphs to trip the exception on a 2GB laptop, the original code is more complicated with multilined graphs etc and takes less iterations to die)

Is making a local copy of variables the only way to do this type of thing? Or am I messing up by passing the arrays in the way I am doing it? Or is chart::clicker at fault?

Many thanks in advance for your prayers and monastic guidance.

Update: It seems that although if I copy the arrays as described less memory is leaked, some is still leaked. If I copy the arrays as described the dataset I have (today) is able to complete (and not die) on the machine I am using but the process still grows with every call to the graph drawing sub. If I don't copy the arrays its not even able to complete. Since I will have to process larger datasets than the one I am testing with I don't even seem to have a workaround (apart from writing out temp files or some other kludge).

In reply to Out of memory using chart::clicker by Peterpion

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