FIX: A query plan is not cached in SQL Server 2005 when the text of the hint is a large object

This article describes the following about this hotfix release:

• The issues that are fixed by the hotfix package
• The prerequisites for installing the hotfix package
• Whether you must restart the computer after you install the hotfix package
• Whether the hotfix package is replaced by any other hotfix package
• Whether you must make any registry changes
• The files that are contained in the hotfix package

Consider the following scenario. In Microsoft SQL Server 2005, you submit a query that matches a plan guide. The plan guide contains a hint. The text of the hint is a large object. In this scenario, the query plan is not cached. Therefore, each invocation of the query requires a new compilation to create a query plan.

Note One example of a hint that experiences this problem is the USE PLAN hint. The USE PLAN hint contains a text-based XML Showplan that the optimizer should try to use.

This problem occurs because SQL Server does not cache queries that contain large object literals. SQL Server does not cache these queries so that the procedure cache memory is not wasted. When the hint that is contained in the plan guide is a large object, SQL Server marks the query plan as ineligible for caching. SQL Server does this even though the hint does not require any memory space in the compiled query plan.

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. 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.

Prerequisites

• SQL Server 2005 Service Pack 1 (SP1)
  
  For information about how to obtain SQL Server 2005 SP1, 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

Restart information

You do not have to restart the computer after you apply this hotfix.

Registry information

You do not have to change the registry.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

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 item in Control Panel.

SQL Server 2005 hotfix, 32-bit

SQL Server 2005 hotfix, 64-bit

SQL Server 2005 hotfix, 64-bit for Itanium processors

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

For more information, click the following article number to view the article in the Microsoft Knowledge Base: