Microsoft KB Archive/253283

= SMTP Performance Degradation with Large Number of Messages =

Article ID: 253283

Article Last Modified on 2/28/2007

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APPLIES TO


 * Microsoft Windows 2000 Advanced Server

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This article was previously published under Q253283





SYMPTOMS
The Simple Mail Transport Protocol (SMTP) service in Windows 2000 may experience performance problems when a computer has tens of thousands of messages queued.



CAUSE
This behavior occurs because the SMTP service uses the number of messages to control how many handles it keeps open, instead of using the number of opened handles itself. If there is a large number of messages queued up for a remote system that is down, other messages that could be processed end up being subjected to redundant handle openings and closures.



RESOLUTION
To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

260910 How to Obtain the Latest Windows 2000 Service Pack

The following files are available for download from the Microsoft Download Center:

US English

Download Q262259_w2k_sp1_x86_en.exe now

French

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German

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Italian

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Japanese

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Spanish

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For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to Obtain Microsoft Support Files from Online Services

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STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows 2000 Service Pack 1.



MORE INFORMATION
Currently, the policy of closing handles begins when the total number of messages in the system reaches 1,000. This state can occur because of a large queue to a remote system being in a retry state. Ideally, handles would be closed on messages that are not expected to be processed in the immediate future, but not on others. An example would be to close handles for messages in a queue associated with a slow but active connection to a remote server, leaving open those handles that are associated with messages that have not yet been categorized. Alternatively, use a global policy of closing handles in a manner similar to Microsoft Exchange 5.5, but have the policy start only when the total number of messages with open handles reaches a certain threshold, instead of using the total number of messages in the system to trigger the policy.

Keywords: kbhotfixserver kbqfe kbdownload kbbug kbenv kbfix kbgraphxlinkcritical kbwin2000sp1fix KB253283

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