Microsoft KB Archive/937745

= FIX: You may receive error messages when you try to log in to an instance of SQL Server 2005 and SQL Server handles many concurrent connections =

Article ID: 937745

Article Last Modified on 11/20/2007

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APPLIES TO


 * Microsoft SQL Server 2005 Developer Edition
 * Microsoft SQL Server 2005 Enterprise Edition
 * Microsoft SQL Server 2005 Standard Edition
 * Microsoft SQL Server 2005 Standard X64 Edition
 * Microsoft SQL Server 2005 Standard Edition for Itanium-based Systems
 * Microsoft SQL Server 2005 Enterprise X64 Edition
 * Microsoft SQL Server 2005 Enterprise Edition for Itanium-based Systems
 * Microsoft SQL Server 2005 Workgroup Edition

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Bug #: 50001317 (SQL Hotfix)



Notice
Microsoft distributes Microsoft SQL Server 2005 fixes as one downloadable file. Because the fixes are cumulative, each new release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2005 fix release.



SUMMARY
This article describes the following about this hotfix release:
 * The issues that are fixed by the hotfix package
 * The prerequisites for installing the hotfix package
 * Information about whether you must restart the computer after you install the hotfix package
 * Information about whether the hotfix package is replaced by any other hotfix package
 * Information about whether you must make any registry changes
 * The files that are contained in the hotfix package



SYMPTOMS
When you log in to an instance of SQL Server 2005, error messages that resemble the following are logged in the SQL Server Errorlog file:

Error message 1

2007-03-27 12:01:28.45 Logon Error: 18456, Severity: 14, State: 23.

Error message 2

2007-03-27 12:01:28.45 Logon Login failed for user '. [CLIENT: ]

Additionally, error messages that resemble the following may be logged in the SQL Server Errorlog file if an existing connection is reused in the connection pool:

2007-04-23 13:18:09.380 spid4371 Error: 18056, Severity: 20, State: 29.

2007-04-23 13:18:09.380 spid4371 The client was unable to reuse a session with SPID, which had been reset for connection pooling. This error may have been caused by an earlier operation failing. Check the error logs for failed operations immediately before this error message.

When this problem occurs, you may also experience the following symptoms:
 * High CPU usage occurs.
 * The Microsoft Windows operating system frequently performs context switches.

This problem occurs when SQL Server handles many concurrent connections on a computer that has many processors installed. Additionally, a time-out may occur when you run a query.



CAUSE
This problem occurs because memory allocation contention causes a slowdown on the login process or the query execution process.



RESOLUTION
A supported hotfix is now available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might 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, submit a request to Microsoft Online Customer Services to obtain the hotfix. To submit an online request to obtain the hotfix, visit the following Microsoft Web site:

http://go.microsoft.com/?linkid=6294451

Note If additional issues occur or any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. To create a separate service request, visit the following Microsoft Web site:

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

Prerequisites
You must have SQL Server 2005 Service Pack 2 (SP2) installed to apply this hotfix.

For more information about how to obtain SQL Server 2005 Service Pack 2, click the following article number to view the article in the Microsoft Knowledge Base:

913089 How to obtain the latest service pack for SQL Server 2005

Restart information
You do not have to restart the computer after you apply this hotfix.

Registry information
You do not have to change the registry.

Hotfix file information
This hotfix contains only those files that are required to correct the issues that this article lists. This hotfix may not contain of all the files that you must have to fully update a product to the latest build.

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 item in Control Panel.

SQL Server 2005 x64-based version


STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section.



MORE INFORMATION
For more information about the naming schema for SQL Server updates, click the following article number to view the article in the Microsoft Knowledge Base:

822499 New naming schema for Microsoft SQL Server software update packages

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

Keywords: kbfix kbqfe kbpubtypekc kbexpertiseadvanced kbhotfixserver kbsql2005engine KB937745

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