KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q124709: PATCH: Out of Memory Error w/ AddNew/Update on Dynaset/Table

Article: Q124709
Product(s): Microsoft Visual Basic for Windows
Version(s): 3.0
Operating System(s): 
Keyword(s): kbpatchkbbuglist kbfixlist
Last Modified: 02-NOV-2001

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

- Microsoft Visual Basic Professional Edition for Windows, version 3.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

Performing an AddNew and then and Update method on a table or dynaset causes the
Jet database engine to allocate a small amount of memory that is not released
until the Jet database engine is unloaded from memory. Therefore, programs that
perform many Updates over a long period of time without unloading the Jet
database engine will eventually result in an "Out of Memory" error.

RESOLUTION
==========

There are two possible workarounds:


Update Vbdb300.dll to version 3.00.0530, dated 1 Feb 95 by downloading
Vbdb300.exe. You can find Vbdb300.exe, a self-extracting file, on these
services: The following file is available for download from the Microsoft
Download Center:

  Vbdb300.exe
  (http://download.microsoft.com/download/vb30/Patch/1/W9XNT4/EN-US/vbdb300.exe)

For additional information about how to download Microsoft Support files, click
the article number below to view the article in the Microsoft Knowledge Base:

  Q119591 How to Obtain Microsoft Support Files from Online Services

Microsoft used the most current virus detection software available on the date of
posting to scan this file for viruses. Once posted, the file is housed on secure
servers that prevent any unauthorized changes to the file.

  NOTE: This version of the Vbdb300.dll does require the VB/Access
  compatibility layer (Comlyr.exe) and the updated Jet engine in the Access
  Service Pack (Accsvc.exe in the GO MSACCESS forum).

  DISCLAIMER: The version of Vbdb300.dll (hereinafter the "Product") is being
  released as a patch (the "Patch") in order to fix a specific problem a few
  customers are experiencing with Microsoft Visual Basic 3.0. This Patch has
  been tested comprehensively to ensure that no errors or additional problems
  are introduced into the Product during normal usage. However, in order to
  release this Patch as quickly as possible, it has not have been subjected to
  the same series of rigorous functional and regression tests that are used for
  regular production products. Consequently, this Patch should be installed
  only if you are experiencing the specific problem mentioned above, and not
  applied indiscriminately. Use of this Patch is governed by all of the
  provisions of the Microsoft End User Software License Agreement included with
  the Product, as if it were the Product.

  In addition, the Patch is provided to you at no additional charge. Microsoft
  Corporation owns all right, title and interest in and to the Patch.

  Copyright 1995 Microsoft Corporation, All Rights Reserved.

-OR-

Periodically shell to another Visual Basic program that does not use the Jet
database engine to unload the database application. This will cause all of the
memory held by the Jet database engine to be released back to the system. You
can then restart your application from the non-database program.

STATUS
======

This bug in Microsoft Visual Basic for Windows version 3.0 was corrected with
Vbdb300.dll version 3.00.0530 dated 1 Feb 95.


MORE INFORMATION
================

This problem is not corrected by using the Microsoft Access 2.0/Visual Basic 3.0
Compatibility Layer; nor is it corrected by using the Microsoft Access version
2.0 Service Pack.

Steps to Reproduce Behavior
---------------------------

NOTE: You will need the older version 3.00.0529 of Vbdb300.dll and the
Professional Edition of Visual Basic to reproduce the problem outlined below.

1. Create a new project. Form1 is created by default.

2. Add a label control to Form1.

3. Enter the following code for Form1:

     'Enter the following lines as one line

     Declare Function GetFreeSpace Lib "kernel" (ByVal flag As Integer) _
        As Long

     Sub Form_Activate ()
        Dim lngStartMem As Long
        Dim lngUsedMem As Long
        Dim lngRec As Long
        Dim strMsg as String
        Dim dbBiblio As Database
        Dim dsAuthors As Dynaset

        Label1.Caption = "Initializing..."
        Label1.Refresh

        Set dbBiblio = OpenDatabase("biblio.mdb")
        Set dsAuthors = dbBiblio.CreateDynaset("Authors")
        lngStartMem = GetFreeSpace(0)

        BeginTrans
        For lngRec = 1 To 100000
           dsAuthors.AddNew
           dsAuthors("Au_ID") = lngRec + 100
           dsAuthors("Author") = "Doe, John"
           dsAuthors.Update
           If lngRec Mod 500  = 0 Then
              CommitTrans
              lngUsedMem = lngStartMem - GetFreeSpace(0)
              strMsg = "Records: " & CStr(lngRec) & Chr$(13) & Chr$(10)
              strMsg = strMsg & "Used: " & CStr(lngUsedMem)
              Label1.Caption = strMsg
              Label1.Refresh
              BeginTrans
           End If
        Next
        CommitTrans

        dsAuthors.Close
        dbBiblio.Close
     End Sub

4. Run the program. The "Used:" line of the label tells how much memory has been
  allocated from the global memory heap. This memory is not recovered until you
  exit from Visual Basic.

Additional query words: 3.00 leak low adding comlyr accsvc

======================================================================
Keywords          : kbpatch kbbuglist kbfixlist
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB300Search kbVB300
Version           : :3.0

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

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.