Error Requested unknown parameter

rafasw

 "columns": [
            { "data": 0 },
            { "data": 1 },
            { "data": 2 },
            { "data": 3 },
            { "data": 4 },
            { "data": 5 },
            { "data": 6 },
            { "data": 7 },
            { "data": null,
             "render": function(data, type, campo, meta){
               if(type === 'display'){
                  data = '<button type="button" class="btn btn-inverse-info waves-effect waves-light " data-toggle="tooltip" data-placement="top" title="" data-original-title="Editar" aria-describedby="tooltip647345"><a target="_blank" href="?acao=Alterar&id_usuario='+ campo[0] +'"><i class="zmdi zmdi-edit" style="font-size:20px; color:#0A94E1"></i></a></button> <button type="button" class="btn btn-inverse-danger waves-effect waves-light " data-toggle="tooltip" data-placement="top" title="" data-original-title="Excluir"><a href="?Excluir=ok&id_usuario='+ campo[0] +'" onClick="return pergunta();"><i class="zmdi zmdi-delete" style="font-size:20px; color:#C80306"></i></a></button>'
                   
                   ;
               }

               return data;
            },
             defaultContent:'',
           },

solved, now I'm only worried about one thing, why does it seem "serverSide" is slower?