MySQL Bugs: #28637: Pooled connections are corrupted

Bug #28637	Pooled connections are corrupted
Submitted:	23 May 2007 23:09	Modified:	16 Aug 2007 7:50
Reporter:	Nick dAlterio	Email Updates:
Status:	No Feedback	Impact on me:	None
Category:	Connector / NET	Severity:	S2 (Serious)
Version:	5.0.7, 5.1.0	OS:	Any
Assigned to:		CPU Architecture:	Any
Tags:	ADO.NET, DataReader, pooling

Description:
The following code segment is triggered by a button press in a dialog. The first time the button is pressed it works perfectly. The second time it is pressed I get an IndexOutOfRangeException exception when I call recdr.GetOrdinal("ColName"). The column exists in the data base and was retrieved successfully in the first run.

Looking at the Connection object I noticed, hadBeenOpen = true so it seems like a pooled connection has been used for the second run. I then tried turning off connection pooling via the connection string and it works every time !

This workaround is obviously not an ideal solution to the problem 

It appears that the connection pooling functionality is broken in this case

How to repeat:
Run this more than once

using ( MySqlConnection con = new MySqlConnection( "..." ) )
{
 try
 {
  con.Open();
  using (MySqlCommand reccmd = new MySqlCommand("sp_GetAnswers", con))
  {
    reccmd.CommandType = CommandType.StoredProcedure;
    MySqlParameter custidpar = new MySqlParameter("custid", MySqlDbType.String);
    custidpar.Direction = ParameterDirection.Input;
    custidpar.Value = custid;
    reccmd.Parameters.Add(custidpar);
    using (MySqlDataReader recdr = reccmd.ExecuteReader())
    {
      if (recdr.Read())
      {
         recdr.GetOrdinal("ColName");        /// BANG
      }
    }
  }
 }
 catch (MySqlException dbe)
 {
   MessageBox.Show(dbe.Message);
 }
 catch (Exception e)
 {
   MessageBox.Show(e.Message);
 }
}

Suggested fix:
Disable connection pooling

Updated severity to correct value

Thanks for your report Nick and sorry, I completely missed it.

Nick, can you please post complete test case together with DDL statements. Also, I don't see any cleanup code in your sample.

Example:
    MySqlConnection conn = new MySqlConnection();
    conn.ConnectionString = "DataSource=localhost;...";
    conn.Open();
    MySqlCommand cmdCreateTable = new MySqlCommand("DROP PROCEDURE IF EXISTS `test`.`SP_BUG28637`", conn);
    cmdCreateTable.CommandType = CommandType.Text;
    cmdCreateTable.CommandTimeout = 0;
    cmdCreateTable.ExecuteNonQuery();
    cmdCreateTable.CommandText = "DROP TABLE IF EXISTS `test`.`bug28637`";
    cmdCreateTable.ExecuteNonQuery();
    cmdCreateTable.CommandText = "CREATE TABLE `test`.`bug28637` (" +
--<cut>--
        " ) ENGINE=MyISAM";
    cmdCreateTable.ExecuteNonQuery();
    cmdCreateTable.CommandText = ("CREATE PROCEDURE `test`.`SP_BUG28637`(" + "\n" +
--<cut>--
        ") \n" +
        "BEGIN INSERT INTO bug28637 (`ID`, NAME) VALUES (P_ID, P_NAME); END\n");
etc...

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".