Assume that you have configured Microsoft SQL Server 2008 R2 to use SQL databases or log files on a remote Server Message Block (SMB) network file share. This SMB network file share is located on a computer that is running Windows 7, Windows Server 2008 R2, or Windows Storage Server 2008 R2. In this situation, SQL Online Transaction Processing (OLTP) performance is slower than expected.
This issue occurs when you have workloads that perform noncached mixed read/write I/O disc operations on a single file.
You may experience decreased performance if you perform an OLTP benchmark, such as TPC-C.
If you inspect the PhysicalDisk performance counters for the disk that stores the SQL database files, the average disk queue length is fairly small.
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 the problem described in this article. 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.
To apply this hotfix, you must be running one of the following operating systems:
Windows 7 Service Pack 1 (SP1)
Windows Server 2008 R2
Windows Server 2008 R2 Service Pack 1 (SP1)
Additionally, you must have SQL Server 2008 R2 installed on the computer.
For more information about how to obtain a Windows 7 or Windows Server 2008 R2 service pack, click the following article number to view the article in the Microsoft Knowledge Base:
976932 Information about Service Pack 1 for Windows 7 and for Windows Server 2008 R2
To use the hotfix in this package, you do not have to make any changes to the registry.
You must restart the computer after you apply this hotfix.
Hotfix replacement information
This hotfix does not replace a previously released hotfix.
The global version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.
Windows 7 and Windows Server 2008 R2 file information notes
The files that apply to a specific product, milestone (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:
Windows 7 and Windows Server 2008 R2
Windows 7 and Windows Server 2008 R2
The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2008 R2 and for Windows 7" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.
This hotfix updates Rdbss.sys which handles the outbound network I/O so this hotfix must be installed on the client computers that cause the network I/O in question. If you are storing SQL Server databases on SMB file shares, apply this hotfix on all SQL Server computers.
For all supported x86-based versions of Windows 7
For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2
For all supported IA-64-based versions of Windows Server 2008 R2
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about support for network database files in SQL Server, click the following article number to view the article in the Microsoft Knowledge Base:
304261 Description of support for network database files in SQL Server
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
Additional file information
Additional file information for Windows 7 and for Windows Server 2008 R2
Additional files for all supported x86-based versions of Windows 7
Windows Storage Server 2008 R2, Windows Server 2008 R2 Datacenter, Windows Server 2008 R2 Enterprise, Windows Server 2008 R2 for Itanium-Based Systems, Windows Server 2008 R2 Foundation, Windows Server 2008 R2 Standard, Windows Web Server 2008 R2, Windows 7 Enterprise, Windows 7 Professional, Windows 7 Ultimate