JqGrid Performance - setRowData lags - performance

Question

setRowData takes almost 5 seconds when the grid has 300 rows, 30 cols, and 4 frozen cols.
$("#tbl").jqGrid({
gridview: true,
url: '../controller/GetData',
datatype: "json",
rowNum: pageSize,
viewrecords: true,
loadtext: '',
loadui: 'disable',
rowList: [1000, 2000, 3000],
width: $(window).width() - LeftMargin,
shrinkToFit: false,
pager: '#dvPager',
pagerpos: 'left',
colNames: GetColNames(selectedViewName, viewCols),
colModel: GetColModel(selectedViewName, viewCols),
cmTemplate: {
title: false
},
recordtext: "Displaying {0} - {1} of {2}",
rowattr: function (rowData) {
},
//onCellSelect: function (rowid, iCol, cellcontent, e) {
// e.stopPropagation();
// proto.editcell(rowid, iCol, cellcontent, e);
//},
loadComplete: function (data) {..},
onPaging: function (data) {..},
serializeGridData: function (postData) {..}
});
Can you please guide me with the performance tuning tips?
In GetColModel we are binding columns as follows -
'Discount': {
name: 'Discount', index: 'Discount', width: colModelWidthDict['Discount'], title: false, sortable: false, resizable: colResizable, hidden: !bReadCalculationSellInfo,
formatter: function (cellValue, option, rowObject) {
if (rowObject.level == 0 || (rowObject.Flag == 0 && (rowObject.Discountable && rowObject.Discountable.toLowerCase() == 'no')))
return '';
else {
if (!proto.IsReadOnly(rowObject) && ((rowObject.Flag == 0 && (rowObject.Discountable && rowObject.Discountable.toLowerCase() == 'yes')) || rowObject.Flag > 0))
return proto.GetControls("Discount", option.rowId, "Numeric", rowObject.Discount, 6, 90)
else
return '<span class="amt">' + cellValue + '</span>';
}
},
unformat: function (cellValue, option) {
return cellValue;
},
cellattr: function (rowId, val, rowObject, cm, rdata) {
if (parseInt(rowObject.PPPChngDisc) == 1)
return ' style="color:red"';
}
}
//code for colModel - 1 column above

Answer 1

In general you should prefer to modify only small number of rows. If you modify one row then the web browser have to recalculate position of all other rows (500 rows) of the grid. In the case modifying 300 rows means 300*500 operations for the web browser.
If you fill the whole grid and you use gridview: true option then jqGrid places at the beginning all the data for the grid body in array of strings. After preparing of all information in string format jqGrid place the whole body of the grid as one operation. It's just one assigning innerHTML property of tbody. Thus it's more effective to reload the whole grid as to make modification of many rows of the grid in the loop using setRowData.
So I would recommend you to reload the grid in your case.
Moreover you should consider to reduce the number of rows in the page of grid. If you use rowNum: 500 you just reduce the performance of your page tin many times without any advantage for the user. The user can see about 20 rows of the data only. Only if the user scrolls he/she is able to see another information. In the same way the user could click next page button. Holding 500 rows force web browser make a lot of unneeded work. Modifying of the first row from 500 the web browser have to recalculate position of all 500 rows. Even if the user move the mouse over a row the web browser change the class of the hovering row and it have to recalculate position of all other from 500 rows event the rows are not visible.
One more remark. The implementation of frozen columns in jqGrid 4.6 is slow. Starting with the end of 2014 and publishing 4.7.1 with changing Lisanse and making jqGrid commercial I develop free jqGrid as fork based on jqGrid 4.7 (see the readme for more details). I implemented a lot of changes and new features in the fork. The recent changes includes many improvement of frozen columns feature. If you loads free jqGrid or just try it directly from GitHub by including the corresponding URLs (see the wiki) you will see that the performance of frozen columns is dramatically improved. Additionally frozen columns supports now row and cell editing in all editing modes. I plan to publish free jqGrid 4.9 soon. So I recommend you to try it.
UPDATED: You posted the code, which you use in comments below. I see the main problem in the implementation of Process function which will be called on change in the <input> fields on the grid. I recommend you to try something like this one:
function Process(contrl) {
var $cntrl = $(contrl),
$td = $cntrl.closest("tr.jqgrow>td"),
$tr = $td.parent(),
rowId = $tr.attr("id"),
newValue = $cntrl.val(),
$grid = $("#list"),
p = $grid[0].p,
colModel = p.colModel,
columnName = colModel[$td[0].cellIndex].name, // name of column of edited cell
localRowData = $grid.jqGrid("getLocalRow", rowId),
iColTotal = p.iColByName.total;
// modify local data
localRowData[columnName] = newValue;
localRowData.total = parseInt(localRowData.quantity) * parseFloat(localRowData.unit);
// modify the cell in the cell (in DOM)
//$grid.jqGrid("setCell", rowId, "total", localRowData.total);
$($tr[0].cells[iColTotal]).text(localRowData.total);
return false;
}
One can event improve the code and not use setCell at all. It's important to understand that local grid hold the data in the form of JavaScript object. The access to the data is very quickly. You can modify the data without any side effects existing with DOM elements. In the above code I use only relative search inside of the DOM of the row using closest and parent. It works very quickly. I recommend to save $("#list") in the variable outside of the Process (move var $grid = $("#list") in the outer function) and just use $grid variable. It will make access to the DOM of page very quickly. The line localRowData = $grid.jqGrid("getLocalRow", rowId) get the reference to internal JavaScript data object which represent the internal data of the row. By modifying the data by localRowData[columnName] = newValue; or localRowData.total = ... we make the half of job. One need only to change the value in the DOM on the cell Total. I used iColByName which exist in the latest sources of free jqGrid on GitHub. It get just the column index in colModel by column name. One can find the same information alternatively if one use more old jqGrid. The line $($tr[0].cells[iColTotal]).text(localRowData.total); shows how to assign manually the data in the cell. It's the most quick way to do this, but one assign the data without the usage formatter. For more common case (for example in case of frozen "total" column) one can use the commented row above: $grid.jqGrid("setCell", rowId, "total", localRowData.total);.