Yii上传文件失败

I am uploading a file using a fileField form CActiveForm and it works for 'small' files, but when I upload a larger file, the page just reloads with a blank form and nothing in either the $_POST or $_FILES variable.

My form has 'htmlOptions'=>array('enctype'=>'multipart/form-data' and the post_max_size and upload_max_filesize are both set to 100M in php.ini

I'm using Yii 1.1.14 and PHP 5.5.12.

The file model, nothing special

class DocumentUploadModel extends CFormModel {
    public $thefile;

    public function rules () {
        return array (
            array ('thefile', 'file', 'types' => 'pdf'),
        );
    }
}

The filefield, also nothing special

<div class="row">
    <?php echo $form->labelEx($documentFile,'thefile'); ?>
    <?php echo $form->fileField($documentFile,'thefile'); ?>
    <?php echo $form->error($documentFile,'thefile'); ?>
</div>

Var dumps from small file, 344KB (top = $_POST, bottom is $_FILES

And the same for a larger file, 22.405K

I hope somebody can help me!

edit the validation rule to:

array ('thefile', 'file', 'types' => 'pdf', 'allowEmpty'=>false),

Change the file upload size limit as per your requirement in php.ini and apache config.