use strict;
use DBI;
use Furl;

my $dbh = DBI->connect( ... );
my $sth  = $dbh->prepare( "SELECT object_id ... WHERE storage_id = ? ORDER BY object_id DESC" );


my $furl = Furl::HTTP->new;
my $object_id;
$sth->bind_columns( \($object_id) );
while ( $sth->fetchrow_arrayref ) {
     # XXX ERROR CHECKING et al IS DELIBERATELY SKIPPED IN THIS EXAMPLE
     my $url = make_url( $object_id, $storage_id );
     my @res = $furl->get( $url );

     my $count = get_needed_copy_count( $object_id );
     my @storages = get_destination_storages( $object_id );
     while ( $count > 0 && @storages ) {
           my $new_storage = shift @storages;
           if ( migrate_to_storage( $furl, $object_id, $res[4], $new_storage ) ) {
                $count--;
           }
     }
     if ($count > 0) {
           # Failed to copy?
     }
}

use strict;
use Coro;
use DBI;
use FurlX::Coro;

my $dbh = DBI->connect( ... );
my $sth  = $dbh->prepare( "SELECT object_id ... WHERE storage_id = ? ORDER BY object_id DESC" );

my $sem = Coro::Semaphore->new(10);
my $object_id;
$sth->bind_columns( \($object_id) );
while ( $sth->fetchrow_arrayref ) {
     my $guard = $sem->guard;
     async_pool {
          my $guard = shift;
          process( $object_id );
     } $guard;
}

Coro::AnyEvent::sleep 1 while $sem->count < 10; # WAIT


sub process {
    my $furl = FurlX::Coro::HTTP->new( ... );

}

while ( ... ) {
      async_pool {
          ....
      }
}

cede while $sem->count < 10;

use Parallel::ForkManager;

my $WORKERS = 10;
my $pfm = Parallel::ForkManager->new($WORKERS);

my $max_object_id = get_max_object_id_in_storage( $storage_id );
my $min_object_id = get_min_object_id_in_storage( $storage_id );
my $diff = $max_object_id - $min_object_id;
if ( my $remainder = $diff % $WORKERS ) {
    $diff += $remainder;
}
my $segment_size = $diff / $WORKERS;


for my $i ( 1..$WORKERS ) {
     $min_object_id = $max_object_id - $segment_size;
     if (my $pid = $pfm->start) {
          $max_object_id = $min_object_id;
          next;
     }
     process( $max_object_id, $min_object_id );
     $pfm->finish;
}

sub process {
     my $dbh =  ...;
     my $sth = $dbh->prepare("SELECT ... FROM ... WHERE object_id <= ? and object_id > ?" );

     my $sem = Coro::Semaphore->new(10);
     $sth->execute( $max_object_id, $min_object_id );
     my $object_id;
     $sth->bind_columns( \($object_id) );
     while ( $sth->fetchrow_arrayref ) {
          my $guard = $sem->guard;
          async_pool {
               my ($guard, $object_id) = @_;
               ....
          } $guard, $object_id;
     }
}

my $sth = $dbh->prepare( <<EOSQL );
    SELECT object_id FROM entity WHERE
          object_id <= ?
          ORDER BY object_id DESC
          LIMIT 5000,1
EOSQL

while( $loop ) {
    $sth->execute( $max_object_id );
    if ( my $pid = $pfm->start ) {
         $max_object_id = $min_object_id;
         next;
    }
    process( $max_object_id, $min_object_id );
    $pfm->finish;
}

   #!perl
   exec "/bin/ls"

   #!perl
   END { do_interesting_stuff() }

   exec "/bin/ls"