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Q276200: BUG: ADO Application May Hang When Using OLE DB Provider for DB2

Article: Q276200
Product(s): Microsoft SNA Server
Version(s): 4.0 SP2,4.0 SP3
Operating System(s): 
Keyword(s): kbDSupport kbsna400sp2 kbsna400sp3 kbSNA400sp4fix kbSNA400PreSP4fix
Last Modified: 13-JUN-2001

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

- Microsoft SNA Server, versions 4.0 SP2, 4.0 SP3 
-------------------------------------------------------------------------------

SYMPTOMS
========

An Active Data Object (ADO) application that leverages the OLE DB Provider for
DB2 may intermittently stop responding (hang) when the data source is configured
to use the Transfer Control Protocol/Internet Protocol (TCP/IP) transport to the
remote system.

The following Visual Basic sample code shows a typical code-loop scenario in
which this problem may occur:

   ...
   ...
     If (rsChrgs.State And adStateOpen) = adStateOpen Then

          While Not bDone
          
              vaRows = rsChrgs.GetRows(100)  
              nTotalRows = UBound(vaRows, 2)
              For nRow = 0 To nTotalRows
                  DoEvents
                  If bCancel Then Exit Function
              Next
              bDone = (nTotalRows < 99)
          Wend
      
      End If
   ...
   ...

A call to the GetRows function may block indefinitely so that control is not
returned to the calling function. The application hangs at this point.

CAUSE
=====

When the OLE DB Provider for DB2 receives a Distributed Data Management (DDM)
General Data Stream (GDS) header that is split across multiple TCP/IP packets,
the provider does not work correctly (fails). No errors are reported to the
Microsoft Windows NT Application Event Log when the provider fails.

RESOLUTION
==========

To resolve this problem, obtain the latest service pack for SNA Server 4.0. For
additional information, please see the following article in the Microsoft
Knowledge Base:

  Q215838 How to Obtain the Latest SNA Server Version 4.0 Service Pack



STATUS
======

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

This problem was first corrected in SNA Server 4.0 Service Pack 4.


Additional query words: Ddmtcp sp3 sp2

======================================================================
Keywords          : kbDSupport kbsna400sp2 kbsna400sp3 kbSNA400sp4fix kbSNA400PreSP4fix 
Technology        : kbAudDeveloper kbSNAServSearch kbSNAServ400SP2 kbSNAServ400SP3
Version           : :4.0 SP2,4.0 SP3
Issue type        : kbbug
Solution Type     : kbfix

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