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="Big Table.aspx.cs"
AutoEventWireup ="false" Inherits="BigTa ble.BigTable" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
<title>BigTable </title>
<meta name="GENERATOR " Content="Micros oft Visual Studio .NET 7.1">
<meta name="CODE_LANG UAGE" Content="C#">
<meta name="vs_defaul tClientScript" content="JavaSc ript">
<meta name="vs_target Schema"
content="http://schemas.microso ft.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="lblRowsToLo ad" style="Z-INDEX: 104; LEFT: 8px;
POSITION: absolute; TOP: 152px"
runat="server" Width="144px">R ows To Load</asp:Label>
<asp:TextBox id="txtRowsToLo ad" 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="btnLoa dRows_Click"></asp:Button>
</form>
</body>
</HTML>
BigTable.aspx.c s:
using System;
using System.Data;
namespace BigTable
{
public partial class BigTable : System.Web.UI.P age
{
protected System.Web.UI.W ebControls.Data Grid grdRows;
protected System.Web.UI.W ebControls.Butt on btnLoadRows;
protected System.Web.UI.W ebControls.Text Box txtRowsToLoad;
protected System.Web.UI.W ebControls.Labe l lblRowsToLoad;
protected void btnLoadRows_Cli ck(object sender,
System.EventArg s e)
{
System.Data.Dat aTable dt = new DataTable();
for (int x = 0; x < 10; x++) //10 columns
{
dt.Columns.Add( x.ToString(), typeof(String)) ;
}
System.Data.Dat aRow dr;
int yTotal = int.Parse(txtRo wsToLoad.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.DataSou rce = dt;
grdRows.DataBin d();
}
}
}
BigTable.aspx.d esigner.cs:
//------------------------------------------------------------------------------
// <auto-generated>
// This code was generated by a tool.
// Runtime Version:2.0.507 27.42
//
// 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.H tmlControls.Htm lForm Form1;
}
}
