MCE is a new Perl module recently added to CPAN. This is how one may use MCE to process in Parallel. MCE is both a chunking and parallel engine. In this case, chunk_size is set to 1. That option is not needed as calling the foreach method will set it to 1 anyway.

The sendto method can be used to serialize data from workers to a file. MCE also provides a do method as well to pass data to a callback function which runs from the main process.

$chunk_ref is a reference to an array. MCE provides both foreach and forchunk methods. In this case, the array contains only 1 entry due to chunk_size being set to 1.

The main page at http://code.google.com/p/many-core-engine-perl/ contains three images. The 2nd one shows the bank queuing model used in MCE with chunking applied to it.

use MCE;

## Parse command line argument for $database_list

my $mce = MCE->new(
   max_workers => 4,
   chunk_size  => 1
);

$mce->foreach("$database_list", sub {
   my ($self, $chunk_ref, $chunk_id) = @_;

   my $database = $chunk_ref->[0];
   my @result = ();

   ## Query the database

   $self->sendto('file:/path/to/result.out', @result);
});
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