FIX: A federated database server stops responding when you run parallel queries on a multiprocessor computer that uses NUMA architecture in SQL Server 2005

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
• 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

Consider the following scenario. On a multiprocessor computer, you install more than one instance of Microsoft SQL Server 2005 that uses non-uniform memory access (NUMA) architecture. These instances compose a federated database server. In this scenario, when you run parallel queries, the CPU utilization of the server may increase to 100 percent. Additionally, the federated database server stops responding. If you run the following statement on one of the instances to examine the information about each request, the value of the wait_type column of many requests is CMEMTHREAD.

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, 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

To apply this hotfix, you must have SQL Server 2005 Service Pack 2 installed. 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, x64-based version

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

This hotfix is scheduled to be included in Cumulative Update Package 5 for SQL Server 2005 Service Pack 2. Cumulative Update Package 5 introduces new global trace flag 8048. If you cannot resolve this issue by applying this hotfix, you can try to use global trace flag 8048 to resolve the issue after you install Cumulative Update Package 5. You can enable the global trace flag when the SQL Server service starts. Global trace flag 8048 converts all the memory objects that are partitioned by a NUMA node into memory objects that are partitioned by CPU. Global trace flag 8048 may remove contention from the CMEMTHREAD wait type on a symmetric-multiprocessing (SMP) computer that has many CPUs or on a NUMA computer that has many CPUs for each node.

Note If you enable this global trace flag, we recommend that you monitor performance after you apply any other hotfixes or cumulative update packages. You may experience performance decreases after you apply other hotfixes or cumulative update packages.

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