Microsoft KB Archive/944902

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

Article ID: 944902

Article Last Modified on 12/13/2007

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APPLIES TO


 * Microsoft SQL Server 2005 Standard X64 Edition
 * Microsoft SQL Server 2005 Enterprise X64 Edition

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Bug: #50002030 (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
 * 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



SYMPTOMS
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. select * from sys.dm_exec_requests



Hotfix information
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 Microsoft SQL Server 2005 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
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:

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
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:

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: kbsql2005engine kbexpertiseadvanced kbfix kbpubtypekc kbqfe kbhotfixserver KB944902

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