Passing ADODB::Field object to ADO Command.CreateParameter method causes a memory leak (817518)


The information in this article applies to:

  • Microsoft Data Access Components 2.8
  • Microsoft Data Access Components 2.7 SP1
  • Microsoft Data Access Components 2.7
  • Microsoft Data Access Components 2.6
  • Microsoft Data Access Components 2.5

SYMPTOMS

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.

CAUSE

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.

RESOLUTION

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it 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 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product 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. 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

WORKAROUND

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

STATUS

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

MORE INFORMATION

Do not pass a Field object to the CreateParameter() method because this slows performance.
Modification Type:MinorLast Reviewed:10/11/2005
Keywords:kbHotfixServer kbQFE kbfix kbQFE KB817518 kbAudDeveloper
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