Large data handling problem in jquery data table, giving error

var $table=$('#MCNRes').dataTable
( {
"bFilter": false,
"bDestroy": true,
"bJQueryUI": true,
"bServerSide": true,
"sDom": '<"H"l<"toolbar">Tfr>t<"F"ip>',
"ajax": {
url: 'getResult.php',
type: 'POST'
}

});

Server side data fetching and forming json string

$result = $afscpMcnMod->getMcnDetails();// function fetch data from DB
$newarray = array(
"draw" => $_POST['draw'],
"recordsTotal" => sizeof($result),
"recordsFiltered" => sizeof($result),
"data" => $result
);
echo json_encode($newarray);