MySQL server error report:Array
(
    [0] => Array
        (
            [message] => MySQL Query Error
        )

    [1] => Array
        (
            [sql] => SELECT cat_id, cat_name, parent_id FROM `OK_ELEC`.`ok_category`
        )

    [2] => Array
        (
            [error] => MySQL server has gone away
        )

    [3] => Array
        (
            [errno] => 2006
        )

)