BUG: Handle Leak when Passing ADO Objects Between Processes

ID: Q197426

The information in this article applies to:

ActiveX Data Objects (ADO), version 2.0

SYMPTOMS

When marshalling an ActiveX Data Objects (ADO) recordset between processes the handle count incrementally increases for each call made to the out-of- process component. This behavior only occurs if the rowset contains more than 8K of data.

CAUSE

Microsoft has confirmed this to be a problem in ActiveX Data Objects Version 2.0.

RESOLUTION

A supported fix that corrects this problem is now available from Microsoft, but it has not been fully regression tested and should be applied only to systems experiencing this specific problem. If you are not severely affected by this specific problem, Microsoft recommends that you wait for the next Microsoft Data Access Components service pack (or the next version) that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web:

   http://support.microsoft.com/support/supportnet/default.asp

The English version of this fix should have the following file attributes or later:

   Date      Time    Version      Size     File name   Platform
   ------------------------------------------------------------

   11/19/98  13:32   2.0.3002.25  279,824  Msadce.dll  (x86)
   11/19/98  13:38   2.0.3002.25  731,136  Msadce.dll  (Alpha)

This hot fix (Ado8k.exe) is engineered to work with Microsoft Data Access Components (MDAC) build 2.0 Service Pack 1 (SP1) and should only be applied to this specific build. To verify the build of MDAC, check the internal version number of Mdado15.dll, which should be 2.0.3002.23.

Installation Instructions:

1. Locate the Msadce.dll on the target computer.

2. Check the version number, it should be 2.0.3002.23.

3. Copy the new Msadce.dll over the existing one.

4. Register the .dll file using the following:

      RegSvr32 Msadce.dll

NOTE: If you contact Microsoft to obtain this fix, a fee may be charged. This fee is refundable if it is determined that you only require the fix you requested. However, this fee is non-refundable if you request additional technical support, if your no-charge technical support period has expired, or if you are not eligible for standard no-charge technical support.

For more information about eligibility for no-charge technical support, see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q154871
   TITLE:      Determining If Your Product Is Eligible for No-Charge
               Technical Support

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article.

MORE INFORMATION

Steps to Reproduce the Behavior

NOTE: The following steps assume that you are using Visual Basic 5.0 or

      later.

1. Build an ActiveX .EXE that creates a disconnected recordset with ADO

   2.0.

2. Use the following SQL statement against the Pubs (SQL Server 6.5)

   database to produce a recordset that contains more than 8K of data:

      (SELECT authors.*, roysched.*, titleauthor.*, titles.*, publishers.*
      FROM titleauthor INNER JOIN authors ON titleauthor.au_id =
      authors.au_id INNER JOIN titles ON titleauthor.title_id =
      titles.title_id INNER JOIN roysched ON titles.title_id =
      roysched.title_id INNER JOIN publishers ON titles.pub_id =
      publishers.pub_id).

3. Pass the recordset as the return value of a function in the .exe.

4. Create a client application that creates an instance of the .exe and

   calls the recordset returning function from the .exe.

5. It is important to maintain the scope of the .exe between calls.

6. Repeat the call process to the .exe several times.

7. Open the performance monitor and check the handle count for the .exe in

   the image list under the Processes tab. You will see the handle count
   increase by 2(+/-1) for each call you make to the component.

Additional query words:

Keywords          : kbADO200bug kbADO200fix kbADO200QFE 
Version           : WINDOWS:2.0
Platform          : WINDOWS
Issue type        : kbbug
Solution Type     : kbfix

Last Reviewed: December 18, 1998