Microsoft KB Archive/933564

= FIX: A gradual increase in memory consumption for the USERSTORE_TOKENPERM cache store occurs in SQL Server 2005 =

Article ID: 933564

Article Last Modified on 11/20/2007

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APPLIES TO


 * Microsoft SQL Server 2005 Developer Edition
 * Microsoft SQL Server 2005 Enterprise Edition
 * Microsoft SQL Server 2005 Enterprise X64 Edition
 * Microsoft SQL Server 2005 Standard Edition
 * Microsoft SQL Server 2005 Standard X64 Edition

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Bug: #50000945 (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 applying the hotfix package
 * Whether you must restart the computer after you apply the hotfix package
 * Whether the hotfix package is replaced by any other hotfix package
 * Whether you must make any registry changes after you apply the hotfix package
 * The files that are contained in the hotfix package



SYMPTOMS
When a custom application that is running on Microsoft SQL Server 2005 uses features that trigger frequent database protection timestamp changes, a gradual increase in memory consumption for the USERSTORE_TOKENPERM cache store occurs. Additionally, many duplicate TokenAccessResult entries have a class of 65535 in the sys.dm_os_memory_cache_entries dynamic management view.

For more information about the issue and about conditions that cause protection timestamp changes for a database, see the &quot;More information&quot; section.



CAUSE
This problem occurs because the cumulative permission check of a query is stored in the USERSTORE_TOKENPERM cache store as a TokenAccessResult entry that has a class of 65535. TokenAccessResult entries use the protection timestamp to determine whether security changes have occurred that would invalidate the cache entry. Every time that the protection timestamp changes, the old cache entries cannot be reused because the old entries may not be current. Therefore, a new cache entry must be inserted. However, an old entry is not removed until SQL Server experiences memory pressure. This problem can lead to an increase in memory consumption by the USERSTORE_TOKENPERM cache store.



RESOLUTION
A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that is described in this article. Apply it only to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Microsoft SQL Server 2005 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Customer Support Services to obtain the hotfix. For a complete list of Microsoft Customer Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

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

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

Prerequisites
You must have Microsoft SQL Server 2005 Service Pack 2 (SP2) installed to apply this hotfix.

For more information about how to obtain SQL Server 2005 Service Pack 2, 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
You do not have to restart the computer after you apply this hotfix.

Registry information
You do not have to change the registry.

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, 64-bit versions


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
You can use the following two queries to determine whether you are experiencing this issue.   When you run the following query, you notice that memory consumption by the USERSTORE_TOKENPERM cache increases: select sum(single_pages_kb+multi_pages_kb) 'total memory for tokeperm' from sys.dm_os_memory_clerks where type = 'USERSTORE_TOKENPERM'   When you run the following query, you receive many entries in the Store Address column and in the ID column: select [Store Address], [id], count (*) 'number of entries' from (select         cast(entry_data as xml).value ('(//@store_address)[1]', 'varchar (100)') as [Store Address],         cast(entry_data as xml).value ('(//@id)[1]', 'bigint') as [id]         from sys.dm_os_memory_cache_entries        where type = 'USERSTORE_TOKENPERM' and cast(entry_data as xml).value ('(//@name)[1]', 'varchar (100)') = 'TokenAccessResult' and             cast(entry_data as xml).value('(//@class)[1]', 'bigint') = 65535    ) R group by [Store Address], [id] having count (*) > 1 order by count (*) desc If this query produces no results, you are not experiencing the issue that this article describes. 

Many conditions change the database protection timestamp. For example, most Data Definition Language (DDL) operations change the protection timestamp.

The Create Table DDL operation and the Drop Table DDL operation for temporary tables changes the protection timestamp in the tempdb database.

The following DDL operations are Transact-SQL statements. These operations change the protection timestamp in the master database:
 * Create Login
 * Alter Login
 * Drop Login
 * Create Endpoint
 * Alter Endpoint
 * Drop Endpoint

The following DDL operations are related to user objects, such as the table object. These operations change the protection timestamp in any database. These databases include the master database and the tempdb database.
 * Create
 * Alter
 * Drop

The following DDL operations are related to security. All security-related operations change the protection timestamp in any database. These databases include the master database and the tempdb database. The following list names some examples of security-related DDL operations.
 * Create
 * Alter
 * Drop user
 * Role
 * Application role
 * Certificate
 * Schema
 * Symmetric keys
 * Asymmetric keys

Additionally, operations that grant, revoke, or deny permissions on an object are related to security. These operations also change the protection timestamp in any database. These databases include the master database and the tempdb database.

Other conditions can also cause the USERSTORE_TOKENPERM cache to grow over time. The fix that this article describes is for a very specific condition. That is, a change in the protection timestamp causes the cache store to grow. For more information about the USERSTORE_TOKENPERM cache, click the following article number to view the article in the Microsoft Knowledge Base:

927396 Ad hoc queries take a longer time to finish running when the size of the TokenAndPermUserStore cache grows in SQL Server 2005

After you install this hotfix, a new attribute that is named timestamp is added to entry_data columns in the sys.dm_os_memory_cache_entries view. This attribute specifies the number of times that SQL Server checks the permissions on each plan. When a plan is newly compiled or is recompiled, the timestamp is 1. This value is recalculated if the protection timestamp changes. You can use the following query to take snapshots of the timestamp: select [store_address], [timestamp], count (*) 'number of entries' from (select cast(entry_data as xml).value ('(//@store_address)[1]', 'varchar(100)')  as store_address, case cast(entry_data as xml).value ('(//@timestamp)[1]', 'int') when  1 then 1         else  null         end as [timestamp]         from sys.dm_os_memory_cache_entries        where type = 'USERSTORE_TOKENPERM' and cast(entry_data as xml).value ('(//@name)[1]', 'varchar (100)') = 'TokenAccessResult' and             cast(entry_data as xml).value('(//@class)[1]', 'bigint') = 65535    ) R group by [store_address], [timestamp] order by count (*) desc If over time you see many timestamps of 1 for each store_address column, an application has a high rate of ad hoc queries or of recompile operations. You must slow down the rate of the ad hoc queries or of the recompile operations. Alternatively, you can address the issue by applying trace flag 4618 to limit the number of entries per user cache store. Using trace flag 4618 can incur a small CPU overhead because this trace flag removes old cache entries as new entries are inserted. The trace flag performs this action to limit the size of the cache store growth. However, the CPU overhead is spread over time.



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

824684 Description of the standard terminology that is used to describe Microsoft software updates

Keywords: kbqfe kbprb kbsql2005engine KB933564

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