Symptoms
Assume that you use SQL Server 2008 R2 Analysis Services. When you perform a processing operation on a dimension in Analysis Services, and the service is under memory pressure, the dimension data may be corrupted.
Note This issue occurs in a relatively rare race condition which is not pervasive. When this issue occurs, you may experience incorrect dimension relationships or ProcessUpdate failures.
Here are some conditions and behaviors that are observed for this issue:
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Analysis Services memory usage exceeds the high memory limit configured for the service during the processing operation. This causes Analysis Services to aggressively clean memory pages.
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No error or message logs that the problem has occurred during processing, and the dimension processing will not fail. It completes and writes corrupted data to the dimension file.
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The issue is most likely to manifest itself as incorrect dimension attribute relationships for newly added dimension members. For example: A member in the Product dimension may appear under the incorrect Category or Subcategory.
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Another way this corruption can reveal itself is a subsequent ProcessUpdate on a dimension that contains Rigid attribute relationships. The dimension processing may fail with the following error message:
'Rigid relationships between attributes cannot be changed during incremental processing of a dimension
Note This error can also occur for legitimate reasons, such as changes in the underlying data source. However, if the underlying data in the table or view that serves as the source for the dimension has not changed, this could be the cause of the error.
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The issue does not always occur when the server is under memory pressure, but it occurs if the cleaner thread evicts a data page for newly added dimension members, before the dimension processing is complete. This is a relatively rare race condition between the dimension processing thread and the memory cleaner threads in the Analysis Services service.
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After this fix is installed the issue will no longer occur, but the impacted objects will need to be reprocessed to resolve the issue.
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A ProcessUpdate on an impacted dimension when the server is not under memory pressure will correct corruption that has been caused by this issue for all flexible relationships. For an impacted dimension that has one or more rigid attribute relationships, the processing will fail with the error mentioned above.
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To correct the issue for dimensions that are containing rigid relationships, alter the attribute relationships for the impacted dimension on the server and then run a ProcessUpdate. The attribute relationship can then be changed back to rigid and the indexes for the measure groups that use the dimension will be rebuilt.
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Note After you apply this hotfix, the SQL Server version will be 10.50.6548.0.
Resolution
Hotfix information
A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that's described in this article. Apply this hotfix only to systems that are experiencing this specific problem.
If the hotfix is available for download, there's a "Hotfix Download Available" section at the top of this Knowledge Base article. If this section does not appear, submit a request to Microsoft Customer Service and Support to get 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 don't qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, go to the following Microsoft website:
http://support.microsoft.com/contactus/?ws=supportNote The "Hotfix Download Available" form displays the languages for which the hotfix is available. If you don't see your language, it's because a hotfix isn't available for that language.
Restart information
You don't have to restart the computer after you apply this hotfix.
Registry information
You don't have to change the registry after you apply this hotfix.
Hotfix replacement information
This hotfix doesn't replace any other hotfixes.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
