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Passing ADODB::Field object to ADO Command.CreateParameter method causes a memory leak

View products that this article applies to.


When you pass an ActiveX Data Objects (ADO) Field object as a parameter value to the Command.CreateParameter method, a memory leak occurs. When you do this repeatedly, Performance Monitor shows a steady increase in both the private and virtual bytes.

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This is caused by a bug in Microsoft Data Access Components (MDAC). Because of this bug, ADO does not release an internal BSTR. This causes memory to leak.

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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 this specific problem. 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. The English version of this fix has the file attributes (or later) 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 tool in Control Panel.

MDAC 2.7 SP1

     Date         Time   Version            Size    File name
   27-Mar-2003  22:30  2.71.9031.41      487,424  Msado15.dll      

MDAC 2.8

    Date         Time   Version            Size    File name
   18-Feb-2004  13:28  2.80.1033.0       512,000  Msado15.dll

   18-Feb-2004  13:28  2.80.1033.0       163,840  Msadomd.dll

   18-Feb-2004  13:28  2.80.1033.0       184,320  Msadox.dll

   18-Feb-2004  13:28  2.80.1033.0        53,248  Msadrh15.dll

   18-Feb-2004  13:29  2000.85.1033.0     24,576  Odbcbcp.dll

   18-Feb-2004  13:28  2000.85.1033.0    401,408  Sqlsrv32.dll

Note For a list of all the hotfixes available for MDAC 2.8, click the following article number to view the article in the Microsoft Knowledge Base:
839801 FIX: Hotfixes are available for MDAC 2.8

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Pass the value of the Field object instead of the Field object itself.

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

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More information

Do not pass a Field object to the CreateParameter() method because this slows performance.

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Keywords: kbautohotfix, kbhotfixserver, kbqfe, kbfix, kbqfe, KB817518

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Article Info
Article ID : 817518
Revision : 8
Created on : 11/15/2007
Published on : 11/15/2007
Exists online : False
Views : 408