FIX: Blocking and performance problems may occur when you enable trace flag 1118 in SQL Server 2005 if the temporary table creation workload is high

This article describes the following about this hotfix release:

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

In Microsoft SQL Server 2005, you may notice blocking and performance-related problems. You experience this problem if the following conditions are true:

• You enable trace flag 1118.
• The temporary table creation workload is high.
• Multiple data files exist for the tempdb database.

In the sysprocesses system table, the value in the waittype column of the tempdb database is set to PAGELATCH.

This problem occurs when multiple data files exist in the tempdb database. When these multiple data files exist, latch waits occur in the Shared Global Allocation Map (SGAM) pages of the tempdb database.

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, contact Microsoft Customer Service and Support to obtain the hotfix.

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. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays 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

You must have Microsoft 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:

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, 32-bit versions

SQL Server 2005, 64-bit version

SQL Server 2005, Itanium architecture version

To work around this problem, disable trace flag 1118. You can interactively disable the trace flag by using the following DBCC TRACEOFF command: You can also specify the trace flag as a startup parameter of the SQL Server service. When you specify the trace flag as a startup parameter, the trace flag is automatically enabled when the SQL Server service starts. If you set the trace flag as a startup parameter, you can still use the DBCC TRACEOFF command to disable the trace flag interactively.

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

The hotfix that this article describes affects only the tempdb database. This hotfix significantly reduces the need to force uniform allocations by using trace flag 1118. If you apply the fix and are still encountering TEMPDB contention, consider also turning on trace flag 1118.

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