Microsoft KB Archive/937360

= An application may experience slow performance if the application frequently uses binary string (BSTR) data types to manage large chunks of data on a Windows Server 2003-based computer =

Article ID: 937360

Article Last Modified on 10/11/2007

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APPLIES TO


 * Microsoft Windows Server 2003, Standard Edition (32-bit x86)
 * Microsoft Windows Server 2003, Web Edition
 * Microsoft Windows Server 2003, Enterprise Edition
 * Microsoft Windows Server 2003, Datacenter Edition (32-bit x86)
 * Microsoft Windows Server 2003, Standard x64 Edition
 * Microsoft Windows Server 2003, Enterprise x64 Edition
 * Microsoft Windows Server 2003, Datacenter x64 Edition
 * Microsoft Windows Server 2003, Enterprise Edition for Itanium-based Systems
 * Microsoft Windows Server 2003, Datacenter Edition for Itanium-Based Systems

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Important This article contains information about how to modify the registry. Make sure that you back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows registry



SYMPTOMS
On a Windows Server 2003-based computer, an application may experience slow performance. This behavior may occur if the application frequently uses binary string (BSTR) data types to manage large chunks of data. Additionally, the application consumes lots of memory in this situation.

Note The same application experiences no performance problems on a Windows 2000-based computer.



CAUSE
This problem occurs because of a design change in the BSTR cache settings in Windows Server 2003. In Microsoft Windows 2000, the maximum BSTR cache bucket size is 128 kilobytes (KB). In Windows Server 2003, the maximum BSTR cache bucket size is 32 KB. The BSTR cache settings cannot be configured either in Windows 2000 or in Windows Server 2003.



RESOLUTION
Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk. After you apply this hotfix, you can adjust the BSTR cache settings in Windows Server 2003 to improve the performance of the application. For example, you can adjust the maximum size for the BSTR cache bucket to 128 KB. To do this, follow these steps:  Click Start, point to Settings, and then click Control Panel. Double-click System. On the Advanced tab, click Environment Variables. Under System variables, click New. In the Variable name box, type OACACHEPARAMS . In the Variable value box, type an appropriate value, and then click OK.

Note After you close the System item in Control Panel, you can use the following command to set the OACACHEPARAMS value:

set OACACHEPARAMS=

For more information about the value that you should use for the OACACHEPARAMS variable, see the &quot;OACACHEPARAMS variable instructions&quot; section.</li> Click OK to close the Environment Variables dialog box.</li> Click OK to close the System Properties dialog box.</li> Restart the computer.</li></ol>

OACACHEPARAMS variable instructions
The variable value should use the following format:

,, , :

By default, the value of the OACACHEPARAMS variable is set to 32768,256,64,32:6. If you want to use the default value for a parameter, replace the parameter with 0 (zero). For example, you can run the following command at a command prompt:

set OACACHEPARAMS=16384,0,128,0:5

If you want to modify only the first few parameters, you can omit the other parameters. For example, if you want to change only the first two parameters, run the following command at a command prompt:

set OACACHEPARAMS=4096,2048

To set the maximum BSTR cache bucket size to 128 KB, run the following command at a command prompt:

set OACACHEPARAMS=131072,256,64,32:6

Hotfix information
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 Windows Server 2003 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
To apply this hotfix, you must have Windows Server 2003 Service Pack 1 or Windows Server 2003 Service Pack 2 installed on the computer. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

889100 How to obtain the latest service pack for Windows Server 2003

Restart requirement
You must restart the computer after you apply this hotfix.

Hotfix replacement information
This hotfix does not replace any other hotfixes.

File information
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.

Windows Server 2003 with Service Pack 2, x64-based versions
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STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section.

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MORE INFORMATION
If the OANOCACHE environment variable is also defined, any setting for the OACACHEPARAMS variable is ignored. For more information about the OANOCACHE environment variable, click the following article number to view the article in the Microsoft Knowledge Base:

139071 FIX: OLE Automation BSTR caching will cause memory leak sources in Windows 2000

For more information about software update terminology, 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

Additional query words: tune

Keywords: kbbug kbfix kbqfe kbpubtypekc kbexpertiseinter kbhotfixserver kbwinserv2003postsp2fix KB937360

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