Symptoms
In Microsoft SQL Server 2008 or SQL Server 2008 R2, you try to back up a database by using the BACKUP statement. However, the backup operation fails, and the following error messages are logged in the SQL Server error log file:
<Date><Time> <spid> Error: 2601, Severity: 14, State: 1.<Date><Time> <spid> Cannot insert duplicate key row in object 'sys.syscommittab' with unique index '<Index Name>'.<Date><Time> <spid> Error: 3999, Severity: 17, State: 1.<Date><Time> <spid> Failed to flush the commit table to disk in dbid <Database ID> due to error 2601. Check the errorlog for more information.
This issue occurs when the following conditions are true:
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You have enabled SQL Server change trackingon this database.
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After change tracking was enabled, the database has undergone database recovery at least once.Note The most common scenarios when database recovery is run are as follows:
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When the SQL Server service is restarted.
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When the database is restored from a backup.
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Additionally, the 2601 error can also be encountered when SQL Server tries to perform a checkpoint operation on this database.For more information about activities that can cause a database checkpoint, refer to the “Activities That Cause a Checkpoint” subtopic of the “Checkpoints and the Active Portion of the Log” section of the following SQL Server 2008 documentation:
Resolution
Cumulative update information
SQL Server 2008 Service Pack 3
The fix for this issue was first released in Cumulative Update 2 for SQL Server 2008 Service Pack 3. For more information about this cumulative update package, click the following article number to view the article in the Microsoft Knowledge Base:
2633143 Cumulative update package 2 for SQL Server 2008 Service Pack 3Note Because the builds are cumulative, each new fix release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2008 fix release. Microsoft recommends that you consider applying the most recent fix release that contains this hotfix. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
2629969 The SQL Server 2008 builds that were released after SQL Server 2008 Service Pack 3 was released Microsoft SQL Server 2008 hotfixes are created for specific SQL Server service packs. You must apply a SQL Server 2008 Service Pack 3 hotfix to an installation of SQL Server 2008 Service Pack 3. By default, any hotfix that is provided in a SQL Server service pack is included in the next SQL Server service pack.
SQL Server 2008 R2 Service Pack 1
The fix for this issue was first released in Cumulative Update 1 for SQL Server 2008 R2 Service Pack 1. For more information about how to obtain this cumulative update package, click the following article number to view the article in the Microsoft Knowledge Base:
2544793 Cumulative Update package 1 for SQL Server 2008 R2 Service Pack 1Note Because the builds are cumulative, each new fix release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2008 R2 fix release. We recommend that you consider applying the most recent fix release that contains this hotfix. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
2567616 The SQL Server 2008 R2 builds that were released after SQL Server 2008 R2 Service Pack 1 was released
SQL Server 2008 R2
The fix for this issue was first released in Cumulative Update 8. For more information about how to obtain this cumulative update package for SQL Server 2008 R2, click the following article number to view the article in the Microsoft Knowledge Base:
2534352 Cumulative Update package 8 for SQL Server 2008 R2 Note Because the builds are cumulative, each new fix release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2008 R2 fix release. We recommend that you consider applying the most recent fix release that contains this hotfix. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
981356 The SQL Server 2008 R2 builds that were released after SQL Server 2008 R2 was released
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
References
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
More Information
To fix a related issue in SQL Server, see the following KB article:Duplicate key rows from the sys.syscommittab table in SQL Server
