RadGrid Grouping very slow

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Hi,

Just started using your RadGrid for ASP.net here at work and have a table with about 500,000 rows that I am testing with.  Sorting/Paging/Filtering all works fine and I am able to build a custom linq query to only return the rows i need to be displayed...but, I'm not having any luck doing that with grouping as I need to return the entire resultset for radgrid to group correctly.

As the rows increase in the database table, so does the time it takes for the page to load when grouped or when performing any type of grouping, i'm using the following code for testing, and currenly have PageSize set to 10, as per the default.

Protected Sub RadGrid1_NeedDataSource(ByVal sender As Object, ByVal e As Telerik.Web.UI.GridNeedDataSourceEventArgs) Handles RadGrid1.NeedDataSource

    Dim db As New TrackerDataContext

    db.Log = New System.Diagnostics.DebuggerWriter

    Dim query = From p In db.posts

                Where p.parentid = 0

                Select p

    If String.IsNullOrWhiteSpace(RadGrid1.MasterTableView.FilterExpression) = False Then

        query = query.Where(RadGrid1.MasterTableView.FilterExpression)

    End If

    For Each exp As GridSortExpression In RadGrid1.MasterTableView.SortExpressions

        query = query.OrderBy(String.Format("{0} {1}", exp.FieldName, exp.SortOrder.ToString))

    Next

    Dim start As Integer = RadGrid1.CurrentPageIndex * RadGrid1.PageSize

    Dim max As Integer = RadGrid1.PageSize

    RadGrid1.AllowCustomPaging = True

    'we always need count

    RadGrid1.VirtualItemCount = query.Count

    If isGrouping Or RadGrid1.MasterTableView.GroupByExpressions.Count > 0 Then

        start = 0

        max = RadGrid1.VirtualItemCount

        RadGrid1.AllowCustomPaging = False

    End If

    RadGrid1.DataSource = query.Skip(start).Take(max)

End Sub



Private isGrouping As Boolean = False

Protected Sub RadGrid1_GroupsChanging(ByVal sender As Object, ByVal e As Telerik.Web.UI.GridGroupsChangingEventArgs) Handles RadGrid1.GroupsChanging

    isGrouping = True

    If e.Action = GridGroupsChangingAction.Ungroup AndAlso RadGrid1.MasterTableView.GroupByExpressions.Count = 1 Then

        isGrouping = False

    End If

End Sub

Is there any way to improve the performance?

Take Care

[Pavlina]

Hello,

Useful tips on how to optimize the RadGrid performance using different techniques can be found in the online resources linked below:
http://www.telerik.com/help/aspnet-ajax/gridoverview.html (Chapter "Performance tips and tricks")
http://www.telerik.com/products/aspnet-ajax/resources/top-performance.aspx
http://www.telerik.com/support/aspnet-ajax.aspx (Section "Performance")

I hope this helps.

All the best,
Pavlina
the Telerik team