This article describes the following about this hotfix release:

•	The issues that are fixed by this hotfix package
•	The prerequisites for installing the hotfix package
•	Whether you must restart the computer after you install the hotfix package
•	Whether the hotfix package is replaced by any other hotfix package
•	Whether you must make any registry changes
•	The files that are contained in the hotfix package

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Consider the following scenario. You have a query that uses a user-defined scalar function. You run the query against an instance of Microsoft SQL Server 2005. In this scenario, the query performance is slow.

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This problem occurs because the SQL Server Database Engine query optimizer performs only a few optimizations for the query. This behavior occurs because many of the optimizations that the query optimizer performs are not safe. Therefore, the query optimizer uses an inefficient query plan for the query.

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Cumulative update information

To resolve this problem, obtain the cumulative update package for SQL Server 2005 Service Pack 2 (build 3161). For more information about how to obtain the cumulative update package (build 3161), click the following article number to view the article in the Microsoft Knowledge Base:

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Hotfix information

A supported hotfix is 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 software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, 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: Note If additional issues occur or if 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: Note The "Hotfix download available" section and the online request forms display the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

To apply this hotfix, you must have SQL Server 2005 Service Pack 2 (SP2) installed on the computer. 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:

Restart information

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

Hotfix file information

The global 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 Database Engine, 32-bit version

File name	File version	File size	Date	Time	Platform
Microsoft.sqlserver.maintenanceplantasks.dll	9.0.3161.0	296,304	03-Apr-2007	15:03	x86
Msmdlocal.dll	9.0.3161.0	15,930,224	03-Apr-2007	15:03	x86
Mssqlsystemresource.ldf	Not applicable	524,288	03-Apr-2007	11:51	Not applicable
Mssqlsystemresource.mdf	Not applicable	40,173,568	03-Apr-2007	11:51	Not applicable
Rdistcom.dll	2005.90.3161.0	644,464	03-Apr-2007	15:03	x86
Sqlaccess.dll	2005.90.3161.0	350,576	03-Apr-2007	15:03	x86
Sqlservr.exe	2005.90.3161.0	29,191,536	03-Apr-2007	15:03	x86
Sysdbupg.sql	Not applicable	510,622	31-Mar-2007	05:24	Not applicable

SQL Server 2005 Database Engine, x64 version

File name	File version	File size	Date	Time	Platform
Microsoft.sqlserver.maintenanceplantasks.dll	9.0.3161.0	296,304	03-Apr-2007	14:03	x86
Msmdlocal.dll	9.0.3161.0	15,930,224	03-Apr-2007	14:03	x86
Mssqlsystemresource.ldf	Not applicable	524,288	03-Apr-2007	10:51	Not applicable
Mssqlsystemresource.mdf	Not applicable	40,173,568	03-Apr-2007	10:51	Not applicable
Rdistcom.dll	2005.90.3161.0	828,272	03-Apr-2007	19:03	x64
Sqlaccess.dll	2005.90.3161.0	357,744	03-Apr-2007	19:03	x86
Sqlservr.exe	2005.90.3161.0	38,534,512	03-Apr-2007	19:03	x64
Sysdbupg.sql	Not applicable	510,622	31-Mar-2007	04:24	Not applicable

SQL Server 2005 Database Engine, Itanium architecture version

File name	File version	File size	Date	Time	Platform
Microsoft.sqlserver.maintenanceplantasks.dll	9.0.3161.0	296,304	03-Apr-2007	14:03	x86
Msmdlocal.dll	9.0.3161.0	49,815,920	03-Apr-2007	21:18	IA-64
Mssqlsystemresource.ldf	Not applicable	524,288	03-Apr-2007	10:51	Not applicable
Mssqlsystemresource.mdf	Not applicable	40,173,568	03-Apr-2007	10:51	Not applicable
Rdistcom.dll	2005.90.3161.0	1,885,040	03-Apr-2007	21:18	IA-64
Sqlaccess.dll	2005.90.3161.0	352,112	03-Apr-2007	21:18	x86
Sqlservr.exe	2005.90.3161.0	72,841,072	03-Apr-2007	21:18	IA-64
Sysdbupg.sql	Not applicable	510,622	31-Mar-2007	04:24	Not applicable

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

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This problem does not occur in SQL Server 2000. SQL Server 2000 does not support nondeterministic system functions within a user-defined function.

After you apply this hotfix, you must turn on the new trace flag 4110 in SQL Server 2005. After you turn on this trace flag, SQL Server 2005 will not support nondeterministic system functions within a user-defined function. You can turn on trace flag 4110 by using the following command.

DBCC TRACEON (4110)

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base: For more information about the user-defined functions in SQL Server 2005, visit the following Microsoft Developer Network (MSDN) Web site:

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