Question

I seem to have the luck to run into the funniest problems while deploying my software.

Setup:

• Windows 2000 Prof.
• .NET 2.0 Application
• Connection to MySQL 5.0 via ODBCConnection using the MySQL ODBC-Connector 3.51.26

I was deploying my application while I was running into this exception:

at System.Data.Odbc.OdbcConnection.HandleError(OdbcHandle hrHandle, RetCode retcode)
at System.Data.Odbc.OdbcDataReader.GetData(Int32 i, SQL_C sqlctype, Int32 cb, Int32& cbActualOut)
at System.Data.Odbc.OdbcDataReader.internalGetString(Int32 i)
at System.Data.Odbc.OdbcDataReader.GetValue(Int32 i, TypeMap typemap)
at System.Data.Odbc.OdbcDataReader.GetValue(Int32 i)
at System.Data.Odbc.OdbcDataReader.GetValues(Object[] values)
at MyAppl.UninterestingStackTace.StartsHere()

Yes, that’s only the stacktrace…because there is no Exception-Message, there’s also no InnerException (I also log those since my last encounter), this is all I got.

The code looks like this:

// DtRdr is a passed in ODBCDataReader
if (DtRdr != null && !DtRdr.IsClosed)
{
    Object[] buffer = new Object[DtRdr.FieldCount];

    while (DtRdr.Read())
    {
        DtRdr.GetValues(buffer); // Here happens the exception

        // Modify buffer and use it
    }
}

It’s only happening on that machine, the fetched data/database is good (verified it via another machine on the same network and I also tested it locally on my dev-machine) and of course it’s not reproducible on any other machine.

While looking at it in Reflector, I realize that it seems to be a problem with reading the data from the connection. All other operations are working fine, I can access the data directly, only GetValues fails.

I wrote a fast and simple test application which yields the same error, but also outputs the following statement after terminating:

Error in my_thread_global_end(): 1 threads didn't exit

I’m not sure if this is related or not, so sorry for the confusion.

I’m lost once again…has anyone seen something like this before?

Edit: Here’s my test application:

using System;
using System.Data;
using System.Data.Odbc;

namespace ODBCTest
{
    class MainClass
    {
        public static void Main (string[] args)
        {
            try {
                Console.WriteLine ("Creating connection...");
                using (OdbcConnection conn = new OdbcConnection ("ConnStringHere")) {
                    conn.Open ();
                    Console.WriteLine ("Creating command...");
                    using (OdbcCommand cmd = conn.CreateCommand ()) {
                        cmd.CommandText = "SimpleSelectHere;";

                        Console.WriteLine ("Creating reader...");
                        using (OdbcDataReader rdr = cmd.ExecuteReader ()) {
                            if (rdr != null && !rdr.IsClosed) {
                                while (rdr.Read ()) {
                                    object[] temp = new object[rdr.FieldCount];
                                    rdr.GetValues (temp);
                                }

                                Console.WriteLine ("Seems to work fine.");
                            } else {
                                Console.WriteLine ("Could not create reader!");
                            }
                        }
                    }
                }
            } catch (Exception ex) {
                Console.WriteLine (ex.Message);
                Console.WriteLine (ex.StackTrace);
                Console.WriteLine ();
                if (ex.InnerException != null)
                {
                    Console.WriteLine (ex.InnerException.Message);
                    Console.WriteLine (ex.InnerException.StackTrace);
                } else {
                    Console.WriteLine("No InnerException.");
                }
            }

            Console.ReadKey ();
        }
    }
}

And it’s output:

Creating connection...
Creating command...
Creating reader...

   at System.Data.Odbc.OdbcConnection.HandleError(OdbcHandle hrHandle, RetCode retcode)
   at System.Data.Odbc.OdbcDataReader.GetData(Int32 i, SQL_C sqlctype, Int32 cb, Int32& cbActualOut)
   at System.Data.Odbc.OdbcDataReader.internalGetString(Int32 i)
   at System.Data.Odbc.OdbcDataReader.GetValue(Int32 i, TypeMap typemap)
   at System.Data.Odbc.OdbcDataReader.GetValue(Int32 i)
   at System.Data.Odbc.OdbcDataReader.GetValues(Object[] values)
   at ODBCTest.MainClass.Main(String[] args)

No InnerException.
<At this point I hit a key>
Error in my_thread_global_end(): 1 threads didn't exit

Answer 1

I’ll be damned! This is a bug in the MDAC 2.7, installing 2.8 (or the hotfix) fixes this.

And the thread-error message is a bug in the used MySQL ODBC-Connector.