数据表（服务器端分页）仅显示两个页面

根据 Headers ，
我的数据表只显示结果的前两页 .
在iDisplayLength中编辑值会导致在单个页面中显示更多或更少的记录，但不会更改数据表仅显示前两页的事实...

这是数据表的初始化：

var datatable = datatableElement.DataTable({
            "responsive": true,
            "searching": false,
            "processing": true,
            "serverSide": true, 
            "iDisplayLength": 20, 
            "lengthChange": false,
            "stateSave": false,
            "aaSorting": [0, 'desc'],  
            "pagingType": "simple",
            "info": false,
            "columnDefs": [
                {"orderable": false, "targets": [1, 2]}
            ],
            "ajax": {
                "url": siteData.ajaxurl,
                "type": 'POST',
                "data": function(data){
                    data.action = "transactions_history";
                    data.startDate = transactionStartDate.val();
                    data.endDate = transactionEndDate.val();
                    data.type = transactionType.val();
                }
            },
            "language": {
                "url": siteData.ajaxurl + "?action=datatable_internazionalization"
            }
        });

这是ajax函数：

public static function ajax_transactions_history()
{
    $start = filter_input(INPUT_POST, 'start') ?: 0;
    $length = filter_input(INPUT_POST, 'length') ?: 20; 
    $draw = intval(filter_input(INPUT_POST, 'draw'));
    $startDate = filter_input(INPUT_POST, 'startDate') ?: '1/1/2010';
    $endDate = filter_input(INPUT_POST, 'endDate') ?: date("n/j/Y");
    $type = filter_input(INPUT_POST, 'type');
    $order_post = filter_input(INPUT_POST, 'order');
    $order = ($order_post['dir'] == 'desc') ? 'ascending' : 'descending';

    // add 1 day in seconds to get records also for end date
    $endTimestamp = strtotime($endDate) + 86410;
    $endDate = date("n/j/Y", $endTimestamp);

    $gs_result = Gs_Api::member_transaction_history($type, $startDate, $endDate, $order, $length, $start);
    $transactions = array();
    if ($type == 'deposit' && isset($gs_result->scriptData) && isset($gs_result->scriptData->deposit)) {
        $transactions = $gs_result->scriptData->deposit;
    } elseif ($type == 'withdrawal' && isset($gs_result->scriptData) && isset($gs_result->scriptData->withdrawal)) {
        $transactions = $gs_result->scriptData->withdrawal;
    }

    $total = (count($transactions) == $length) ? $length + 1 : $length;
    $result['draw'] = $draw;
    $result['iTotalRecords'] = $total;  
    $result['iTotalDisplayRecords'] = $total; 
    $result['data'] = array();
    foreach ($transactions as $transaction) {
        $date = DateTime::createFromFormat ("D F j Y H:i:s", $transaction->time);
        $result_row = array();
        $result_row[] = $date->format('m-d-Y H:i:s'); 
        $result_row[] = $transaction->amount;
        $result_row[] = __('transaction_status_'.$transaction->status, core_plugin::I18N_DOMAIN);
        $result['data'][] = $result_row;
    }

    wp_send_json($result);
}

正如您所看到的，我想在服务器端处理的数据表中显示结果，每次调用记录20条记录并将它们放入单个页面 .
每个数据表的页面只能有20条记录 .
但它搞砸了 . 例如：如果我有60条记录，则表格仅显示前两页 .
如果我尝试将iDisplayLength和$ length更改为10，则数据表应显示6页，每页10条记录，但它只显示两页，每页10条记录 .
我究竟做错了什么？！

更新：问题似乎是$ result ['iTotalDisplayRecords'] = $ total;
如果我删除它，数据表会显示所有记录，但页面数量是无限的 . 由于记录总数为46，我尝试将其设置为50，数据表正确显示3页，每页20条记录（最后一条记录为6条记录） . 但是，如果我设置iTotalDisplayRecords = $ length，它会进入完整的bug模式并将分页阻为两页.......