BUG: Login/Logout Causes 'Max User Connections Connected' Error

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Article ID: 170652 - View products that this article applies to.
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BUG #: 16737 (NT: 6.5)
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Applications that use make/break connections or perform a large number of repetitive logon or logoff operations may cause spurious errors about exceeding the maximum number of configured user connections. The following is the text of an example error message:
Msg 17809: Unable to connect. The maximum number of '100' configured
user connections are already connected...


If you are using ODBC 3.0, you can use connection pooling to reduce the number of connect and disconnect operations. Otherwise, retry the logon operation or keep a persistent connection to SQL Server.


Microsoft has confirmed this to be a problem in Microsoft SQL Server version 6.5 Service Pack 3 and later. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.


For example, if there are five user connections configured, and three copies of an application are run that simply connect and disconnect in a loop, so that the maximum number of connections can never exceed three, spurious errors may still be generated that five users are already connected. Due to time delays introduced when performing these operations across a network, the problem is unlikely to be seen if the application is run remotely from the server.


Article ID: 170652 - Last Review: February 21, 2014 - Revision: 3.1
  • Microsoft SQL Server 6.5 Service Pack 3
  • Microsoft SQL Server 7.0 Standard Edition
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