FIX: You may experience concurrency issues when you run the DBCC INDEXDEFRAG statement in SQL Server 2000

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 apply this hotfix package
• Whether this hotfix package is replaced by any other hotfix package
• Whether you must make any registry changes after you apply this hotfix package
• The files that are contained in this hotfix package

When you run the DBCC INDEXDEFRAG statement, null mode page locks may accumulate on defragmented pages. These page locks may consume server resources. Then, the transactions that accumulate the locks try to escalate the page locks to table locks. The transactions escalate the page locks to try to reduce server resource usage. Because the DBCC INDEXDEFRAG statement takes an exclusive page lock and also causes the lock escalation to occur, you may experience concurrency issues.

Note You can use the sp_lock stored procedure to verify the mode of a lock.

For a list of all publicly released Microsoft SQL Server 2000 Post-Service Pack 4 hotfixes, see the following article in the Microsoft Knowledge Base:

The installer does not install this hotfix correctly on x64-based systems. This installation issue occurs when the following conditions are true:

• The system uses the Advanced Micro Devices (AMD) AMD64 processor architecture or the Intel Extended Memory 64 Technology (EM64T) processor architecture.
  
  Note This issue does not occur on systems that use the Intel Itanium processor architecture.
• The system is running a 64-bit version of the Microsoft Windows Server operating system.
• The system is running a 32-bit version of SQL Server 2000.

We have corrected this installation issue in later builds of SQL Server 2000, starting with version 8.00.2244. When a customer who is running SQL Server 2000 on an x64-based system requests this hotfix, we will provide a build that includes this hotfix and that can be installed correctly on an x64-based system. The build that we provide will be version 8.00.2244 or a later version.

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.

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 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

Microsoft SQL Server 2000 Service Pack 4 (SP4)

For information about how to obtain SQL Server 2000 SP4, see the following article in the Microsoft Knowledge Base:

Restart information

You must restart the computer after you apply this hotfix.

Registry information

You do not have to make changes to the registry after you apply this hotfix.

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 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 tool in Control Panel.

SQL Server 2000, 32-bit versions

SQL Server 2000, 64-bit version

Note Because of file dependencies, the most recent hotfix or feature that contains these files may contain additional files.

To work around this problem, turn on trace flag 1211 on the connection that runs the DBCC INDEXDEFRAG stored procedure. Trace flag 1211 prevents the transactions that accumulate the locks from escalating the page locks to table locks. The null mode locks may still accumulate. If the null mode locks accumulate, you may receive an error message that is similar to the following: Note We only recommend this workaround as a short-term solution. You should only turn on trace flag 1211 for the duration of the DBCC INDEXDEFRAG stored procedure. If you leave the trace flag on continuously, or if you use this trace flag as a startup parameter, you may experience additional issues from the side effects that are associated with this trace flag. We recommend that you only enable this trace flag for the duration of the DBCC INDEXDEFRAG stored procedure to avoid these issues.

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

For more information about the naming schema for Microsoft 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: