Microsoft KB Archive/922852

= FIX: You may experience high CPU utilization across multiple processors when you run a SQL Server 2005 Analysis Services query against a large partition or lots of partitions =

Article ID: 922852

Article Last Modified on 11/4/2007

-

APPLIES TO


 * Microsoft SQL Server 2005 Analysis Services

-



Bug #: 955 (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.



SUMMARY
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
 * Information about whether you must restart the computer after you install the hotfix package
 * Information about whether the hotfix package is replaced by any other hotfix package
 * Information about whether you must make any registry changes
 * The files that are contained in the hotfix package



SYMPTOMS
When you run a SQL Server 2005 Analysis Services query against a large partition or lots of partitions, you may experience high CPU utilization across multiple processors. This problem occurs if the following conditions are true:
 * The Analysis Services query accesses data from a large partition or from a measure group that contains multiple large partitions.
 * A profiler trace indicates that an extended time is spent reading data from partitions.
 * You experience high CPU utilization when SQL Server reads data from partition files.
 * Repeated calls to the Discover method to request the DISCOVER_SESSION schema rowset or repeated calls to the GetSchemaDataSet method consistently display a disproportionately large segment of time in the SESSION_LAST_COMMAND_CPU_TIME_MS column for a single query.

When this problem occurs, other Analysis Services queries that ordinarily return very quickly may be blocked or appear to be serialized behind the long-running Analysis Services query. This problem occurs when the other Analysis Services queries are executed after the long-running Analysis Services query.



Service pack information
To resolve this problem, obtain the latest service pack for SQL Server 2005. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

913089 How to obtain the latest service pack for SQL Server 2005

Hotfix information
A supported hotfix is now 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 service pack that contains this hotfix.

To resolve this problem, submit a request to Microsoft Online Customer Services to obtain the hotfix. To submit an online request to obtain the hotfix, visit the following Microsoft Web site:

http://go.microsoft.com/?linkid=6294451

Note If additional issues occur or 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. To create a separate service request, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Prerequisites
You must have Microsoft SQL Server 2005 Service Pack 1 (SP1) installed to apply this hotfix.

For more information about how to obtain SQL Server 2005 Service Pack 1, click the following article number to view the article in the Microsoft Knowledge Base:

913089 How to obtain the latest service pack for SQL Server 2005

Restart information
After you apply this hotfix, you do not have to restart the computer if the following conditions are true:
 * If Analysis Services is running as a named instance, you stop the SQL Server Browser service before you apply this hotfix.
 * You exit all Analysis Services tools and all client applications before you apply this hotfix.
 * You exit Microsoft Internet Information Services (IIS) before 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 of 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 Analysis Services hotfix, 64-bit for Itanium processors


STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section. This problem was first corrected in SQL Server 2005 Service Pack 2.



MORE INFORMATION
This hotfix addresses a concurrency issue in SQL Server 2005 Analysis Services that may occur if the following conditions are true:
 * The server is accessed by many users at the same time.
 * Two or more users execute ad hoc queries at the same time.
 * The ad hoc queries involve subcubes that are not covered by aggregations.
 * The first query that is executed reads data from a single large partition or from a measure group that contains multiple partitions.

If the performance issue persists after you apply this hotfix, contact Microsoft Customer Support Services if you must have help tuning the server.

For a complete list of Microsoft Customer Support Services telephone numbers, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support.

