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

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.

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.

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:

1.	Click Start, point to Settings, and then click Control Panel.
2.	Double-click System.
3.	On the Advanced tab, click Environment Variables.
4.	Under System variables, click New.
5.	In the Variable name box, type OACACHEPARAMS.
6.	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=<Value> For more information about the value that you should use for the OACACHEPARAMS variable, see the "OACACHEPARAMS variable instructions" section.
7.	Click OK to close the Environment Variables dialog box.
8.	Click OK to close the System Properties dialog box.
9.	Restart the computer.

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

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: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:

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 1, x86-based versions

File name	File version	File size	Date	Time	Platform
Oleaut32.dll	5.2.3790.2993	557,568	18-Aug-2007	14:33	x86

Windows Server 2003 with Service Pack 2, x86-based versions

File name	File version	File size	Date	Time	Platform
Oleaut32.dll	5.2.3790.4134	553,984	18-Aug-2007	14:51	x86

Windows Server 2003 with Service Pack 1, Itanium-based versions

File name	File version	File size	Date	Time	Platform	SP requirement	Service branch
Oleaut32.dll	5.2.3790.2993	3,936,768	19-Aug-2007	05:50	IA-64	SP1	Not applicable
Woleaut32.dll	5.2.3790.2993	557,568	19-Aug-2007	05:50	x86	SP1	WOW

Windows Server 2003 with Service Pack 2, Itanium-based versions

File name	File version	File size	Date	Time	Platform	SP requirement	Service branch
Oleaut32.dll	5.2.3790.4134	3,943,424	20-Aug-2007	02:10	IA-64	SP2	Not applicable
Woleaut32.dll	5.2.3790.4134	553,984	20-Aug-2007	02:10	x86	SP2	WOW

Windows Server 2003, x64-based versions

File name	File version	File size	Date	Time	Platform	SP requirement	Service branch
Oleaut32.dll	5.2.3790.2993	1,115,648	19-Aug-2007	05:49	x64	SP1	Not applicable
Woleaut32.dll	5.2.3790.2993	557,568	19-Aug-2007	05:49	x86	SP1	WOW

Windows Server 2003 with Service Pack 2, x64-based versions

File name	File version	File size	Date	Time	Platform	SP requirement	Service branch
Oleaut32.dll	5.2.3790.4134	1,121,792	20-Aug-2007	02:15	x64	SP2	Not applicable
Woleaut32.dll	5.2.3790.4134	553,984	20-Aug-2007	02:15	x86	SP2	WOW

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

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