FIX: Performance degradation occurs when you use multiple instances of the XmlValidatingReader class (822956)


The information in this article applies to:

  • Microsoft Visual Studio .NET (2003), Professional Edition
  • Microsoft Visual Studio .NET (2003), Enterprise Architect Edition
  • Microsoft Visual Studio .NET (2003), Enterprise Developer Edition
  • Microsoft Visual Studio .NET (2003), Academic Edition
  • Microsoft Visual Studio .NET (2002), Professional Edition
  • Microsoft Visual Studio .NET (2002), Enterprise Architect Edition
  • Microsoft Visual Studio .NET (2002), Enterprise Developer Edition
  • Microsoft Visual Studio .NET (2002), Academic Edition

SYMPTOMS

When you create multiple instances of the XmlValidatingReader class in an application, performance degradation of the application may occur.

CAUSE

Each instance of the XmlValidatingReader class creates a new XmlSchemaCollection object, and the existing collection is added to the new collection object. This uses lots of resources because each instance of the XmlSchemaCollection object in turn creates a synchronized hashtable, a URL resolver, a read/write lock, and a Schema Names object. This might lead to the performance degradation that is mentioned in the "Symptoms" section.

RESOLUTION

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question. The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
   Date 	Time   Version	      Size	       File name     
   ----------------------------------------------------------------
   10-Jul-2003  6:59   1.1.4322.921   1,335,296 bytes  System.XML.dll         
   10-Jul-2003  6:59   1.1.4322.921     569,344 bytes  System.Web.Services.dll
   10-Jul-2003  6:59   1.1.4322.921     323,584 bytes  System.Runtime.Remoting.dll

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

REFERENCES

For more information, click the following article numbers to view the articles in the Microsoft Knowledge Base:

318504 How to validate XML fragments against an XML schema in Visual C# .NET

330311 FIX: Slow performance when you use XmlValidatingReader

Modification Type:MinorLast Reviewed:10/25/2005
Keywords:kbHotfixServer kbQFE kbvs2002sp1sweep kbfix kbBug kbSchema kbXML kbQFE KB822956 kbAudDeveloper
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