according to what it says on the tin, Datatables should be able to "retain row selection over a data reload". But I can't get it to work when using data from ajax.

Here's how I make my table:

  oTable = $('#fileList').DataTable({
    select: true,
    "ajax": {
      "url": "./data.php",
      "type": "GET"
    },
    rowId: 'Index',
    "createdRow": function (row, data, dataIndex) {
      $(row).addClass(data[2]); //set formatting from data[2]
    }
  });

Following the instructions on the reference above I initially used this to refresh the table every five seconds:

setInterval(function () {
    oTable.ajax.reload();
}

But any selected row would unselect every five seconds. So I tried being more explicit: loading the selected rows into an array and re-selecting them inside the setInterval function:

setInterval(function () {
    var selectedRows = [];
    //put all the selected rows into an array:
    sel = oTable.rows('.selected').every(function (rowIdx) {
      selectedRows.push(rowIdx);
    });
    oTable.ajax.reload();
    console.log(selectedRows);
    //select all the rows from the array
    for (var i = 0; i < selectedRows.length; i++) {
      console.log("selecting ",selectedRows[i]);
      oTable.rows(selectedRows[i]).select();
    }
  }, 5000)
});

in the Console if I have a selected row (in this example the third row) I see:

Array [ 2 ]
selecting  2    

Which is as expected, but the rows aren't re-selected. If I type oTable.rows(2).select(); into the console it selects the third row as it should, but it doesn't work from the setInterval block.

I'm guessing that it may have something to do with the rowID property. I've defined the table in HTML like this:

      <table id="fileList" class="display">
        <thead>
          <tr>
            <th>Index</th>
            <th>Status</th>
            <th>Owner</th>
          </tr>
        </thead>
      </table>

and the data comes from a php script which returns an array like

{"data":[["1", "foo", "bar"], ["2", "fuz", "baz"]}

where the first item is the index.