BUG: Oracle ODBC Connectivity Slow with MDAC 2.5/2.6 on Windows 95/98/NT

When using the Microsoft ODBC for Oracle driver that ships with MDAC 2.5 or 2.6, establishing a connection to an Oracle database may take a long time (approximately 11 seconds) on the platforms listed above. This problem does not occur on Microsoft Windows Millennium Edition (Me) or Microsoft Windows 2000.

This problem is partially due to a bug in the version of Mtxoci.dll (1999.6.854.0) that ships with MDAC 2.5 and 2.6.

You can resolve this problem in either of the following ways:

• Replace Mtxoci.dll with an updated version which ships with Windows 2000 or later.
  
  -or-
• Follow the resolution that is described in the following article in the Microsoft Knowledge Base:
  286204� PRB: Slow CGI Performance with Microsoft ODBC for Oracle on Windows NT 4.0

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

Steps to Reproduce Behavior

There are several ways to reproduce this problem; two methods are shown below.

To reproduce the problem from the ODBC datasource administrator, follow these steps:

1. Click either the User DSN or System DSN tab, and then click Add to create a new data source name (DSN).
2. On the Create New Data Source dialog box, select Microsoft ODBC for Oracle, and then click Finish.
3. In the Microsoft ODBC for Oracle Setup dialog box, add the required information, and then click OK.

To reproduce the problem from the ODBC Test tool (in the MDAC SDK), follow these steps:

1. On the Conn menu, select Full Connect.
2. Select a DSN that is associated with the Microsoft ODBC for Oracle driver, add the user name and password, and then click OK.

In both cases, it takes a long time for the connection to be established. If you follow the above steps after updating Mtxoci.dll, you will notice that the time to establish a connection is reduced.