KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q153797: FIX: Memory Leak with ODBC Driver Manager During Connect

Article: Q153797
Product(s): Open Database Connectivity (ODBC)
Version(s): WINDOWS:2.5
Operating System(s): 
Keyword(s): 
Last Modified: 26-AUG-1999

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft Open Database Connectivity, version 2.5 
-------------------------------------------------------------------------------


SYMPTOMS
========

When an ODBC application makes a certain sequence of calls to connect to an ODBC
driver, a memory loss on the order of a few hundred bytes may occur due to a
memory leak in the Driver Manager. The sequence that results in the memory leak
is as follows:

     SQLAllocEnv<BR/>
     SQLAllocConnect<BR/>
     SQLConnect or SQLDriverConnect<BR/>
     SQLDisconnect<BR/>
     SQLFreeConnect<BR/>
     SQLFreeEnv

This leak affects only those applications that connect and disconnect frequently
without ever exiting the application. For SQL Server replication users, this
problem is encountered when a distribution server connects to subscription
servers as an ODBC client.

WORKAROUND
==========

An application can share connections. If an application needs to connect and
disconnect frequently, you can shut down the application periodically. For
example, if an application is running as a Windows NT service, you can
periodically shut down and restart the service in order to clean up the memory
leak.


Under Windows NT and Windows 95, each application has its own memory address
space. After the application is shut down, Windows NT and Windows 95 will clean
up the application's memory space, including the memory leak.

STATUS
======

Microsoft has confirmed this to be a problem in Microsoft Open Database
Connectivity version 2.5.x. This problem has been corrected in Microsoft Open
Database Connectivity version 3.0.x.

Additional query words: 2.50 ODBC DM VC++ VB C++ MSVC FoxPro

======================================================================
Keywords          :  
Technology        : kbAudDeveloper kbODBCSearch kbODBC250
Version           : WINDOWS:2.5
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.