An ODBC application may not run correctly in Windows Server 2003 SP2 if the application allocates a large block of a contiguous memory buffer

Consider the following scenario:

• You have a computer that is running an x86-based version of Windows Server 2003 Service Pack 2 (SP2).
• You start an application that does the following:
  • The application allocates a large block of a contiguous memory buffer. For example, the application allocates a memory�buffer that is more than 700 MB.�
  • The application uses the Open Database Connectivity (ODBC) driver to connect to a database.

In this scenario, the block of the contiguous memory buffer may not be allocated. Therefore, the application may not start. Or, random application failures occur after the application starts.�

Note When you run this application on a computer that is running Windows Server 2003 Service Pack 1 (SP1), this issue does not occur.

This issue occurs because the Odbc32.dll module is rebased at the address 0x48890000. When the Odbc32.dll module is loaded at this address, memory fragmentation of the Windows user address space occurs. Therefore, the issue that is mentioned in the "Symptoms" section occurs.

Hotfix information

A supported hotfix is 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 the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain 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 do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

To apply this hotfix, you must be running Windows Server 2003 Service Pack 2 (SP2).

For more information about how to obtain a Windows Server 2003 service pack, click the following article number to view the article in the Microsoft Knowledge Base:

Registry information

To use the hotfix in this package, you do not have to make any changes to the registry.

Restart requirement

You may have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The English (United States) version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.

Windows Server 2003 file information notes

• In addition to the files that are listed in these tables, this hotfix also installs an associated security catalog file (KBnumber.cat) that is signed with a Microsoft digital signature.

For all supported x86-based versions of Windows Server 2003

To work around this issue, allocate small blocks of a memory buffer instead of a large block. For example, allocate the memory of some small discontinuous memory buffers into a list, and then use this memory as a large memory buffer.

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