FIX: Application Using Microsoft Oracle ODBC Driver Crashes When TNS Does Not Exist (304329)


The information in this article applies to:

  • Microsoft Data Access Components 2.6
  • Microsoft Data Access Components 2.6 SP1
  • Microsoft ODBC for Oracle version 2.5 Build 2.573.7326
  • Microsoft ODBC for Oracle version 2.5 Build 2.573.6526
This article was previously published under Q304329

SYMPTOMS

When connecting with an ODBC connection (with or without a data source name) using the Microsoft ODBC driver for Oracle, if the specified Transparent Network Substrate (TNS) name does not exist for the Oracle server, an application may receive an access violation. This occurs whether using SQLConnect() or SQLDriverConnect().

CAUSE

This problem occurs only when ODBC connection pooling is enabled. When the Microsoft ODBC driver for Oracle returns a connection failure (because the TNS name does not exist), the ODBC Driver Manager pools the failed connection but does not mark the connection as dead. The connection handle is used later and an access violation occurs.

RESOLUTION

To resolve this problem, obtain the latest service pack for SQL Server 2000, the latest service pack for MDAC 2.6, or the MDAC hotfix referenced below: For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

290211 INF: How to Obtain the Latest SQL Server 2000 Service Pack

For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

300635 INFO: How to Obtain the Latest MDAC 2.6 Service Pack

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 Microsoft ODBC for Oracle ODBC driver that contains this hotfix.

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 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 typical 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 should have the following file attributes or later:
   Date           Time   Version        Size      File name     
   ----------------------------------------------------------
   29-JUNE-2001   14:29  3.520.7629.0   221,456   Odbc32.dll

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in SQL Server 2000 Service Pack 2 and MDAC 2.6 Service Pack 2.
Modification Type:MinorLast Reviewed:10/12/2005
Keywords:kbHotfixServer kbQFE kbBug kbDatabase kbfix kbMDAC260fix kbmdac260sp2fix kbOracle kbSQLServ2000preSP2Fix KB304329
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