I'm seeing some unexpected behavior in Framework 2.0 / IIS 5.1 in high
memory usage situations. The first problem I had is that the default
machine.config for Framework 2.0 does not include a memoryLimit entry -
Framework 1.0 was set to 60% by default. But even after adding a
memoryLimit = 60 to my processModel section all available memory still
gets used up and the process dies - the same app under Framework 1.1
returns the requested rows - no matter how many I request.
The other problem I've seen is that after the 2.0 thread dies or is
killed if I return to that page - without clicking the button to
request datarows - memory begins to skyrocket again immediately. It
seems like ASP.NET is somehow remembering what it was doing when it
died and wants to pick up and do it again - which of course leads to
another crash.
Note: I know it's poor practice to load so much data into a grid. I'm
dealing with a huge production legacy application here and we are in
the process of refactoring. In order to take advantage of some third
party tools we upgraded to framework 2.0. At this point we started
having memory problems with some admittedly poorly designed pages that
allow users to pull ridiculous amounts of data. So if your only answer
is "don't pull so much data" well . . . thanks, no kidding.
Here's my sample app - basically it creates a huge datatable and tries
to load it into a grid:
BigTable.aspx:
<%@ Page language="c#" Codebehind="BigTable.aspx.cs"
AutoEventWireup="false" Inherits="BigTable.BigTable" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
<title>BigTable</title>
<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema"
content="http://schemas.microsoft.com/intellisense/ie5">
</HEAD>
<body MS_POSITIONING="GridLayout">
<form id="Form1" method="post" runat="server">
<asp:DataGrid id="grdRows" style="Z-INDEX: 101; LEFT: 1px; POSITION:
absolute; TOP: 1px" runat="server"
Width="792px"></asp:DataGrid>
<asp:Label id="lblRowsToLoad" style="Z-INDEX: 104; LEFT: 8px;
POSITION: absolute; TOP: 152px"
runat="server" Width="144px">Rows To Load</asp:Label>
<asp:TextBox id="txtRowsToLoad" style="Z-INDEX: 103; LEFT: 8px;
POSITION: absolute; TOP: 176px"
runat="server" Width="80px">5</asp:TextBox>
<asp:Button id="btnLoadRows" style="Z-INDEX: 102; LEFT: 8px;
POSITION: absolute; TOP: 200px"
runat="server" Text="Load Rows"
OnClick="btnLoadRows_Click"></asp:Button>
</form>
</body>
</HTML>
BigTable.aspx.cs:
using System;
using System.Data;
namespace BigTable
{
public partial class BigTable : System.Web.UI.Page
{
protected System.Web.UI.WebControls.DataGrid grdRows;
protected System.Web.UI.WebControls.Button btnLoadRows;
protected System.Web.UI.WebControls.TextBox txtRowsToLoad;
protected System.Web.UI.WebControls.Label lblRowsToLoad;
protected void btnLoadRows_Click(object sender,
System.EventArgs e)
{
System.Data.DataTable dt = new DataTable();
for (int x = 0; x < 10; x++) //10 columns
{
dt.Columns.Add(x.ToString(), typeof(String));
}
System.Data.DataRow dr;
int yTotal = int.Parse(txtRowsToLoad.Text);
for (int y = 0; y < yTotal; y++) //Add the requested number
of rows.
{
dr = dt.NewRow();
for (int x = 0; x < 10; x++) //insert a string value
into each column of each row.
{
dr[x] = x.ToString();
}
dt.Rows.Add(dr);
}
grdRows.DataSource = dt;
grdRows.DataBind();
}
}
}
BigTable.aspx.designer.cs:
//------------------------------------------------------------------------------
// <auto-generated>
// This code was generated by a tool.
// Runtime Version:2.0.50727.42
//
// Changes to this file may cause incorrect behavior and will be
lost if
// the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------
namespace BigTable {
public partial class BigTable {
protected System.Web.UI.HtmlControls.HtmlForm Form1;
}
}
