INFO: Do Not Store STA Objects in Session or Application

Article translations Article translations
Article ID: 243543 - View products that this article applies to.
This article was previously published under Q243543
Expand all | Collapse all


Do not store Single-Threaded Apartment (STA) COM components in an Active Server Pages (ASP) Session or Application.


Storing objects that are marked as STAs, such as components produced by Visual Basic (ActiveX DLLs), limit scalability and can negatively impact performance. Storing STAs in Session scope causes thread affinity and defeats the purpose of a thread pool. When an STA component is stored in Session scope, all subsequent ASP requests from the same user (session) must be executed by the thread that created the component.

In general, stateless page-scoped components perform best. Page-scoped components are COM objects that you create and destroy within the same ASP page. If you need to pass state information from page to page, the following article demonstrates possible techniques that do not use Session:
175167 HOWTO: Persist Values Without Session


For additional information, click the article numbers below to view the articles in the Microsoft Knowledge Base:
175167 HOWTO: Persist Values Without Session
243548 INFO: Design Guidelines for VB Components Under ASP


Article ID: 243543 - Last Review: September 17, 2003 - Revision: 3.1
  • Microsoft Active Server Pages 4.0, when used with:
    • Microsoft Internet Information Server 3.0
    • Microsoft Internet Information Server 4.0
kbaspobj kbinfo kbscalability kbthread KB243543

Give Feedback


Contact us for more help

Contact us for more help
Connect with Answer Desk for expert help.
Get more support from