FIX: You receive an incorrect result when you run a query that uses a parallel execution plan in SQL Server 2005 or in SQL Server 2008

Article ID: 976041 - View products that this article applies to.
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.Microsoft distributes Microsoft SQL Server 2008 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 2008 fix release.
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SYMPTOMS

In Microsoft SQL Server 2005 or in Microsoft SQL Server 2008, you run a query that uses a parallel execution plan. In the parallel execution plan, the Merge Semi join uses a Bitmap filtering that contains the PROBE column. In this scenario, you receive an incorrect result when you run the query.

For example, the execution plan may resemble the following:
|--Merge Join(Left Semi Join, MANY-TO-MANY MERGE:([<TableName>].[<ColumnName>])=([<DatabaseName>].[<SchemaName>].[< TableName >].[< ColumnName >]), 
RESIDUAL:([< DatabaseName >].[< SchemaName >].[< TableName >].[< ColumnName >]=[< DatabaseName >].[< SchemaName >].[< TableName >].[< ColumnName >] as [<TableName >].[< ColumnName >]))            
…
|    |--Parallelism(Repartition Streams, Hash Partitioning, PARTITION COLUMNS:([< TableName >].[< ColumnName >]), WHERE:(PROBE([<Bitmap Name>])=TRUE))              
…
|--Bitmap(HASH:([< TableName >].[< ColumnName >]), DEFINE:([Bitmap Name])) 
…
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RESOLUTION

SQL Server 2005 Service Pack 3

The fix for this issue was first released in Cumulative Update 6 for SQL Server 2005 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:
974648
(http://support.microsoft.com/kb/974648/LN/ )
Cumulative update package 6 for SQL Server 2005 Service Pack 3
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 2005 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:
960598
(http://support.microsoft.com/kb/960598/LN/ )
The SQL Server 2005 builds that were released after SQL Server 2005 Service Pack 3 was released
Microsoft SQL Server 2005 hotfixes are created for specific SQL Server service packs. You must apply a SQL Server 2005 Service Pack 3 hotfix to an installation of SQL Server 2005 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.

The release version of SQL Server 2008

Important You must install this fix if you are running the release version of SQL Server 2008.

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, click the following article number to view the article in the Microsoft Knowledge Base:
975976
(http://support.microsoft.com/kb/975976/ )
Cumulative update package 8 for SQL Server 2008
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 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:
956909
(http://support.microsoft.com/kb/956909/ )
The SQL Server 2008 builds that were released after SQL Server 2008 was released

SQL Server 2008 Service Pack 1

Important You must install this fix if you are running SQL Server 2008 Service Pack 1.

The fix for this issue was first released in Cumulative Update 5 for SQL Server 2008 Service Pack 1. For more information about this cumulative update package, click the following article number to view the article in the Microsoft Knowledge Base:
975977
(http://support.microsoft.com/kb/975977/LN/ )
Cumulative update package 5 for SQL Server 2008 Service Pack 1
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 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:
970365
(http://support.microsoft.com/kb/970365/LN/ )
The SQL Server 2008 builds that were released after SQL Server 2008 Service Pack 1 was released
Microsoft SQL Server 2008 hotfixes are created for specific SQL Server service packs. You must apply a SQL Server 2008 Service Pack 1 hotfix to an installation of SQL Server 2008 Service Pack 1. By default, any hotfix that is provided in a SQL Server service pack is included in the next SQL Server service pack.
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WORKAROUND

To work around this issue, use one of the following methods:

Method 1

Include the following option in the query:
OPTION (MAXDOP 1)

Method 2

Run the following statement to set the max degree of parallelism option to 1: 
sp_configure 'max degree of parallelism', 1
go
reconfigure with override
go
Note This method may cause performance degradation on the server. You should not use this method unless you have evaluated it in a testing, or staging, environment.
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STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
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For more information about how to display the execution plan, visit the following Microsoft Developer Network (MSDN) Web site:
http://msdn.microsoft.com/en-us/library/ms189562(SQL.90).aspx
(http://msdn.microsoft.com/en-us/library/ms189562(SQL.90).aspx)
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REFERENCES

For more informationabout the Incremental Servicing Model for SQL Server, click the following article number to view the article in the Microsoft Knowledge Base:
935897
(http://support.microsoft.com/kb/935897/ )
An Incremental Servicing Model is available from the SQL Server team to deliver hotfixes for reported problems
For more informationabout how to obtain SQL Server 2005 Service Pack 3, click the following article number to view the article in the Microsoft Knowledge Base:
913089
(http://support.microsoft.com/kb/913089/ )
How to obtain the latest service pack for SQL Server 2005
For more information about the new features in SQL Server 2005 Service Pack 3 (SP3) and about the improvements in SQL Server 2005 SP3, visit the following Microsoft Web site:
http://go.microsoft.com/fwlink/?LinkId=131442
(http://go.microsoft.com/fwlink/?LinkId=131442)
For more informationabout the naming schema for SQL Server updates, click the following article number to view the article in the Microsoft Knowledge Base:
822499
(http://support.microsoft.com/kb/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
(http://support.microsoft.com/kb/824684/ )
Description of the standard terminology that is used to describe Microsoft software updates
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Properties

Article ID: 976041 - Last Review: October 19, 2009 - Revision: 1.1
APPLIES TO
  • Microsoft SQL Server 2005 Standard Edition
  • Microsoft SQL Server 2005 Developer Edition
  • Microsoft SQL Server 2005 Enterprise Edition
  • Microsoft SQL Server 2005 Standard X64 Edition
  • Microsoft SQL Server 2005 Standard Edition for Itanium-based Systems
  • Microsoft SQL Server 2005 Enterprise X64 Edition
  • Microsoft SQL Server 2005 Enterprise Edition for Itanium-based Systems
  • Microsoft SQL Server 2005 Workgroup Edition
  • Microsoft SQL Server 2008 Developer
  • Microsoft SQL Server 2008 Enterprise
  • Microsoft SQL Server 2008 Standard
  • Microsoft SQL Server 2008 Web
  • Microsoft SQL Server 2008 Workgroup
Keywords: 
kbsurveynew kbfix kbqfe kbexpertiseadvanced KB976041
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