FIX: You receive an "ORA-01012" error message when you connect to an Oracle database by using MSDAORA

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Article ID: 834905 - View products that this article applies to.
Notice
This hotfix is available as part of a cumulative hotfix package. When you receive this hotfix from Microsoft Product Support Services, the article number that is listed in the hotfix package will be 839801 for MDAC 2.8 or 836799 for MDAC 2.7 SP1. For more information, see the following article in the Microsoft Knowledge Base:

MDAC 2.8
839801 FIX: Hotfixes are available for MDAC 2.8
MDAC 2.7 SP1
836799 FIX: Hotfixes are available for MDAC 2.7 Service Pack 1
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SYMPTOMS

You connect to an Oracle database by using the Microsoft OLE DB Provider for Oracle (MSDAORA), and then you end the connection on the server side. When you open a new connection to the Oracle database from your application, you receive the following exception error message:
System.Data.OleDb.OleDbException: Unspecified error
ORA-01012: not logged on

CAUSE

When you end the connection to the Oracle database on the server side while using MSDAORA, the broken connection is returned to the connection pool. The connection pooling code incorrectly interacts with the ResetConnection property of MSDAORA. When this property is not supported by the provider, the pooling code incorrectly interprets that the connection is reset, and that the connection is a valid one. When the client code opens a new connection, the broken connection that was returned to the connection pool may be retrieved. Therefore, you receive the error message that is mentioned in the "Symptoms" section.

RESOLUTION

Hotfix information

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that is described in this article. Apply it only 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 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Customer Support Services to obtain the hotfix. For a complete list of Microsoft Customer Support Services telephone 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 usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
Microsoft Data Access Components (MDAC) 2.8
   Date         Time   Version         Size     File name
   ---------------------------------------------------------
   10-Mar-2004  04:22  2.80.1036.0     225,280  Msdaora.dll
   10-Mar-2004  04:22  2000.85.1036.0   24,576  Odbcbcp.dll
   10-Mar-2004  04:21  2.80.1036.0     442,368  Oledb32.dll
   10-Mar-2004  04:21  2000.85.1036.0  401,408  Sqlsrv32.dll
MDAC 2.7 Service Pack 1
   Date         Time   Version         Size     File name
   ---------------------------------------------------------
   10-Mar-2004  02:19  2000.81.9046.0   61,440  Dbnetlib.dll
   10-Mar-2004  02:20  2.71.9046.0     221,184  Msdaora.dll
   10-Mar-2004  02:15  2.71.9046.0     126,976  Msdart.dll
   10-Mar-2004  02:15  3.520.9046.0    204,800  Odbc32.dll
   10-Mar-2004  02:20  2000.81.9046.0   24,576  Odbcbcp.dll
   10-Mar-2004  02:20  3.520.9046.0     98,304  Odbccp32.dll
   10-Mar-2004  02:16  2.71.9046.0     417,792  Oledb32.dll
   10-Mar-2004  02:19  2000.81.9046.0  471,040  Sqloledb.dll
   10-Mar-2004  02:19  2000.81.9046.0  385,024  Sqlsrv32.dll

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

MORE INFORMATION

Steps to reproduce the behavior

  1. Start Microsoft Visual Studio .NET.
  2. On the File menu, point to New, and then click Project. The New Project dialog box appears.
  3. Under Project Types, click Visual Basic Projects, and then click Console Application under Templates.
  4. In the Name box, type MyApp, and then click OK. By default, the Module1.vb file is created.

    If you are using Microsoft Visual C# .NET, the Class1.cs file is created.
  5. Add the following code at the top:

    Microsoft Visual Basic .NET code
    Imports System
    Imports System.Data.OleDb
    Visual C# .NET code
    using System.Data.OleDb;
  6. Add the following code to the Main procedure:

    Visual Basic .NET code
    Dim cn As OleDbConnection
    Dim cmd As OleDbCommand
    Dim r As OleDbDataReader
    Dim sid As String
    Dim orlcmd As String
    Dim connString As String = "Provider=MSDAORA;DataSource=<data source>;User ID=<user name>;Password=<password>;"
    Try
        'Create a new connection to the Oracle database by using MSDAORA.
        cn = New OleDbConnection
        cn.ConnectionString = connString
        cn.Open()
        cmd = New OleDbCommand
        cmd.CommandText = "SELECT SID , SERIAL# FROM V$SESSION WHERE SID = (SELECT SID FROM V$MYSTAT WHERE ROWNUM=1)"
        cmd.Connection = cn
        r = cmd.ExecuteReader()
        sid = ""
        If (r.Read()) Then
            sid = r.GetValue(0).ToString() + "," + r.GetValue(1).ToString()
        End If
        orlcmd = "Alter System Kill Session '" + sid + "' Immediate;"
        Console.WriteLine("Open the SQL Plus window, run the following command, and then press ENTER:")
        Console.WriteLine(orlcmd)
        Console.ReadLine()
        r.Close()
        cmd.CommandText = "SELECT count(*) from TAB"
        Try
            'Expecting this command to fail because connection has been killed
            r = cmd.ExecuteReader()
        Catch orlex As OleDbException
            Console.WriteLine(orlex.Message)
            cmd.Dispose()
            'Close the bad connection.
            cn.Close()
            System.Threading.Thread.Sleep(1000)
            cn.ConnectionString = connString
            cn.Open()
            cmd = New OleDbCommand
            cmd.CommandText = "SELECT count(*) FROM TAB"
            cmd.Connection = cn
            'This command will fail, but it will work when a new connection is used.
            r = cmd.ExecuteReader()
            If (r.Read()) Then
                Console.WriteLine(r.GetValue(0))
            End If
       End Try
    Catch ex As OleDbException
       Console.WriteLine(ex.ToString())
    End Try
    Console.WriteLine("Press ENTER to exit...")
    Console.ReadLine()
    
    Visual C# .NET code
    OleDbConnection cn;
    OleDbCommand cmd;
    OleDbDataReader r;
    String sid;
    String orlcmd;
    String connString="Provider=MSDAORA;DataSource=<data source>;User ID=<user name>;Password=<password>;";
    try
    {
        //Create a connection to the Oracle database by using MSDAORA.
        cn= new OleDbConnection();
        cn.ConnectionString=connString;
        cn.Open();
        cmd=new OleDbCommand();
        cmd.CommandText="SELECT SID , SERIAL# FROM V$SESSION WHERE SID = (SELECT SID FROM V$MYSTAT WHERE ROWNUM=1)";
        cmd.Connection=cn;
        r=cmd.ExecuteReader();
        sid="";
        if(r.Read())
        {
           sid=r.GetValue(0).ToString()+","+r.GetValue(1).ToString();
        }
        orlcmd="Alter System Kill Session '"+sid+"' Immediate;";
        Console.WriteLine("Open the SQL Plus window, run the following command, and then press ENTER:");
        Console.WriteLine(orlcmd);
        Console.ReadLine();
        r.Close();
        cmd.CommandText="SELECT count(*) from TAB";
        try
        {
            //Expecting this to fail because the connection is killed.
            r=cmd.ExecuteReader();
        }
        catch(OleDbException orlex)
        {
            Console.WriteLine(orlex.Message);
            cmd.Dispose();
            //Close the bad connection.
            cn.Close();
            System.Threading.Thread.Sleep(1000);
            cn.ConnectionString=connString;
            cn.Open();
            cmd=new OleDbCommand();
            cmd.CommandText="SELECT count(*) FROM TAB";
            cmd.Connection=cn;
            //This command will fail, but it will work when a new connection is used.
            r=cmd.ExecuteReader();
            if(r.Read())
            {
               Console.WriteLine(r.GetValue(0).ToString());
            }
        }
    }
    catch(OleDbException ex)
    {
        Console.WriteLine(ex.ToString());
    }
    Console.WriteLine("Press ENTER to exit...");
    Console.ReadLine();
    
    Note Modify the connection string according to your environment.
  7. On the Build menu, click Build Solution.
  8. On the Debug menu, click Start. You see that a command is displayed in the console window.
  9. In Oracle SQL*Plus, run the command that is displayed in the console window.
  10. Press ENTER. In the console window, you see the exception that is mentioned in the "Symptoms" section.

REFERENCES

For more information about the Microsoft OLE DB Provider for Oracle, visit the following Microsoft Developer Network (MSDN) Web site:
http://msdn2.microsoft.com/en-us/library/ms810685.aspx
For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates
The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.

Properties

Article ID: 834905 - Last Review: November 15, 2007 - Revision: 3.6
APPLIES TO
  • Microsoft Data Access Components 2.8
  • Microsoft Data Access Components 2.7 Service Pack 1
Keywords: 
kbhotfixserver kbqfe kbbug kbprovider kbconnectivity kbdatabase kboracle kbfix kbqfe KB834905

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