Question

I have just discovered a nasty memory leak using both each_array() and each_arrayref() from List::MoreUtils.

These three lines of code are part of a subroutine executed four thousand times on each run.
My objective is to give proper format to values already in a hash. I have a fixed number of hash keys and a format string for each hash key.

my %hash = ();
# ...
my $two_arrays = each_arrayref( $field_list, $field_list_format );
while ( my ( $field, $format ) = $two_arrays->() ) {
    $hash{ $field } = sprintf $format, $hash{ $field };
}

If I stick a return; before my $two_arrays ..., the leak disappears. The same return; past the last line makes the leak.

Since the subroutine is part of a daemon program, I noticed the continuous growth of memory ( both VIRT and RES ).

There is something I did wrong? Is there is any memory leak of each_array() or each_arrayref(), I’m not aware of?

• List::MoreUtil ( VERSION 0.22 )
• Perl 5.12.1 ( x86_64 with threads ) on Linux 2.6.32-32-generic ( Ubuntu 10.04 )

Answer 1

List::MoreUtil ( VERSION 0.22 ) is dated July 2006, 5 years ago. The current version is 0.32, is the leak still present in this version? There have been several memory leaks fixed in the last few versions: http://cpansearch.perl.org/src/ADAMK/List-MoreUtils-0.32/Changes