Replies

• pkboucher Posts: 9Questions: 0Answers: 0

  January 2011

  Additional info: when I do get a JSON back from the server, it works (and passed JSONLINT), and when it freezes up and says it has a null JSON, there's no server log message (meaning no request hit the server).
  
  It appears that my server didn't return an invalid JSON, but instead, the jquery code tries to parse something (who knows what) that did not come from the server.
• pkboucher Posts: 9Questions: 0Answers: 0

  January 2011

  A colleague suggested I word my request for help like this:
  
  Hi All,
  We’re using server-side processing via fairly standard code, including the line:
  "sAjaxSource": "/PCICS-TEST/BankerController/doServerSide",
  
  It works as expected most of the time, but we’re getting an intermittent problem about 10% of the time where, when we add a character to a search/filter string, it hangs on ‘processing’ until we refresh the whole browser page. When I check it out in Chrome’s ‘inspect element’ tools, I see several symptoms of the failure:
  1. it shows “Failed to load resource: doServerSide” (as used above in the sAjaxSource line) and
  2. When we look at the elements we have something that looks like an XHR, (it has the expected Request URL, etc) but it isn’t actually doing the GET to the server.
  3. During the hang, any further changes to the search textbox just continue to display the same failure: it isn’t frozen, it’s just caught in this bad-state, with all subsequent entries also triggering the above behavior. Refreshing the page makes the problem go away until next time.
  When we add to the search/filter string and the problem DOESN’T happen, we’re getting the doServerSide resource loading without problems, and it is actually generating an XHR and getting a successful response from the server, etc…
  
  Triggering the problem is not completely reproducible, but seems to happen most often when we either come back after a few minutes away and start search/filtering the table, or when we type rapidly in a search textbox.
  
  Any guidance would be appreciated. I’d be happy to provide more sample code and/or data, but don’t even know what sort of additional info would be helpful at this point.
  
  Thanks!
• allan Posts: 63,400Questions: 1Answers: 10,452 Site admin

  January 2011

  Hi pkboucher,
  
  What I would suggest is replacing the $.getJSON function you are using with $.ajax() and adding an "error" function to it. Here is an example showing the use of $.json - although not with an error function, which is easy enough to add - http://datatables.net/examples/server_side/post.html . In the error handler, you could try an get some information about why the error is occurring - or just log the fact that it has going into the error state - which is wrong in the first place. It would also be worth watching the Firebug console to see if any JS errors are reported.
  
  Allan
• pkboucher Posts: 9Questions: 0Answers: 0

  January 2011

  I simplified the code and it still does the same thing.
  
  If I type slowly and steadily in the column-searches, it works all day, but if I wait about 5 minutes and then type one more character, it freezes up almost every time.
  
  [code]
  var asInitVals = new Array();
  var oTable;
  
  $(document).ready(function() {
  oTable = $('#example').dataTable( {
  "oLanguage": {
  "sLengthMenu": 'Display '+
  '10'+
  '20'+
  '50'+
  '100'+
  '1000'+
  ' records'
  },
  "sPaginationType": "full_numbers",
  "bProcessing": true,
  "bServerSide": true,
  "sAjaxSource": "<%= controllerPath %>doServerSide",
  "aaSorting": [[ 20, "desc" ]]
  } );
  
  //testing col search
  $("tfoot input").keyup( function () {
  /* Filter on the column (the index) of this element */
  oTable.fnFilter( this.value, $("tfoot input").index(this) );
  } );
  
  
  
  /*
  * Support functions to provide a little bit of 'user friendlyness' to the textboxes in
  * the footer
  */
  $("tfoot input").each( function (i) {
  asInitVals[i] = this.value;
  } );
  
  $("tfoot input").focus( function () {
  if ( this.className == "search_init" )
  {
  this.className = "";
  this.value = "";
  }
  } );
  
  $("tfoot input").blur( function (i) {
  if ( this.value == "" )
  {
  this.className = "search_init";
  this.value = asInitVals[$("tfoot input").index(this)];
  }
  } );
  } );
  [/code]
• pkboucher Posts: 9Questions: 0Answers: 0

  January 2011

  The firebug console shows this:
  [code]
  json is null
  [Break On This Error] if ( typeof json.sEcho != 'undefined' )
  [/code]
  but since it never actually hit my server to get the json, I'm not surprised the json is null.
  
  I will try using the ajax with error reporting.
• pkboucher Posts: 9Questions: 0Answers: 0

  January 2011

  I tried this and got the same behavior, and didn't get that 2nd alert (below):
  [code]
  "fnServerData": function ( sSource, aoData, fnCallback ) {
  $.ajax( {
  "dataType": 'json',
  "type": "GET",
  "url": sSource,
  "data": aoData,
  "success": fnCallback,
  "cache": false,
  "error": function (xhr, error, thrown) {
  if ( error == "parsererror" ) {
  alert( "DataTables warning: JSON data from server could not be parsed. "+
  "This is caused by a JSON formatting error." );
  } else {
  alert( "DataTables warning: error " + error + " thrown " + thrown );
  }
  }
  } );
  }
  [/code]
• pkboucher Posts: 9Questions: 0Answers: 0

  January 2011

  Just so you know, I upgraded my server to the latest glassfish, and the problem went away.
• allan Posts: 63,400Questions: 1Answers: 10,452 Site admin

  January 2011

  Ah very interesting - that's good to hear :-). Thanks for the feedback.
  
  Regards,
  Allan