I think your basic logic error is here: 
my $pm = Parallel::ForkManager->new(50);  # 50 forks
my $i = 0;
while(i<50){  # start 50 forks
  $pm->start and next;
  processStream($stream);
  $i++;
  $pm->finish; # do the exit in the child process
}
$pm->wait_all_children();  # and then do nothing

[download]
I'd amend your code to this (adjusting the fork-amount to something sane such as 4): 
# max 4 processes simultaneously
my $pm = Parallel::ForkManager->new(4);
while( .. there are rows to fetch ..){
  $pm->start and next;
  processStream($stream);
  $pm->finish; # do the exit in the child process
}
$pm->wait_all_children();

[download]
The amount of rows to fetch could be 50 or whatever number that you want. Parallel::ForkManager will take care of the queueing and will keep four forks alive as long as there are jobs in the queue.

In reply to Re: Fork vs pThreads by Anonymous Monk
in thread Fork vs pThreads by ThelmaJay

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