Microsoft KB Archive/942906

= FIX: When you run a stored procedure that uses some views in SQL Server 2005, the performance is slow compared to SQL Server 2000 if the views use the JOIN operator and contain subqueries =

Article ID: 942906

Article Last Modified on 10/26/2007

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APPLIES TO


 * Microsoft SQL Server 2005 Enterprise Edition
 * Microsoft SQL Server 2005 Developer Edition
 * Microsoft SQL Server 2005 Workgroup Edition
 * Microsoft SQL Server 2005 Standard Edition

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Bug: #50001859 (SQL Hotfix)



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.



SYMPTOMS
When you run a stored procedure that uses some views that contain subqueries in Microsoft SQL Server 2005, the performance is slower compared to Microsoft SQL Server 2000. This problem occurs if the views use the JOIN operator.



CAUSE
This problem occurs because SQL Server 2005 generates a poor execution plan for this stored procedure. In the execution plan that SQL Server 2005 generates, SQL Server 2005 uses a Table Spool operator. The Table Spool operator returns many rows. Therefore, SQL Server 2005 takes longer to process these rows. However, in the execution plan that SQL Server 2000 generates, SQL Server 2000 uses a Filter operator. The Filter operator returns fewer rows.



RESOLUTION
The fix for this issue was first released in Cumulative Update 4. For more information about how to obtain this cumulative update package for SQL Server 2005 Service Pack 2, click the following article number to view the article in the Microsoft Knowledge Base:

941450 Cumulative update package 4 for SQL Server 2005 Service Pack 2

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:

937137 The SQL Server 2005 builds that were released after SQL Server 2005 Service Pack 2 was released

Microsoft SQL Server 2005 hotfixes are created for specific SQL Server service packs. You must apply a SQL Server 2005 Service Pack 2 hotfix to an installation of SQL Server 2005 Service Pack 2. By default, any hotfix that is provided in a SQL Server service pack is included in the next SQL Server service pack.



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
For more information about what files are changed, and for information about any prerequisites to apply the cumulative update package that contains the hotfix that is described in this Microsoft Knowledge Base article, click the following article number to view the article in the Microsoft Knowledge Base:

941450 Cumulative update package 4 for SQL Server 2005 Service Pack 2

