Regression in MyODBC 3.51.12

Problem:
==========
There's a regression in MyODBC 3.51.12 vs. 3.51.10.


Details:
==========
Using MyODBC with .Net, the OdbcConnection.ConnectionState property=
no longer correctly reflects the connection's state.
(It seems to be a side effect of the removal of auto-reconnection=
logic in MyODBC.)


How to reproduce:
===================3D

Test app (C#):
---------------
using System;
using System.Data;
using System.Data.Odbc;

class MySqlConnectTest {
=09static string user =3D "INSERT USER HERE";
=09static string password =3D "INSERT PASSWORD HERE";
=09static string server =3D "INSERT SERVER HERE";

=09static OdbcCommand connect() {
string c =3D "Driver=3D{MySQL ODBC 3.51 Driver};Server=3D"=
+ server + ";Uid=3D" + user + ";Pwd=3D" + password + ";OPTION=3D3";
OdbcConnection conn =3D new OdbcConnection(c);
conn.Open();
OdbcCommand cmd =3D conn.CreateCommand();
cmd.CommandText =3D "SELECT VERSION()";
return cmd;
=09}

=09static void Main(string[] args) {
OdbcCommand cmd;

Console.Out.WriteLine("Opening connection...");
cmd =3D connect();
cmd.ExecuteNonQuery();

Console.Out.WriteLine("Ok. Kill database or connection now,=
then press Enter.");
Console.In.ReadLine();

// Simulate a continuously running program that use only 1=
connection=.
for (int i =3D 5; i > 0; i--) {
=09try {
if ((cmd.Connection.State | ConnectionState.Open)=
== ConnectionState.Open)
=09Console.Out.WriteLine("Connection state '" + cmd=
..Connection.State + "' - executing query.");
else {
=09Console.Out.WriteLine("Connection state '" + cmd=
..Connection.State + "', opening and executing query.");
=09cmd =3D connect();
}
cmd.ExecuteNonQuery();
=09} catch (Exception e) {
Console.Out.WriteLine("Error: " + e.Message + "\n");
=09}
}
Console.Out.WriteLine("\nDone - press Enter.");
Console.In.ReadLine();
=09}
}
---------------

The above test application is similar to application logic that we use=
to recreate a connection when it has been closed behind our back for=
one reason or another.

You will probably find TCPView from Sysinternals=
(http://www.sysinternals.com) handy to simulate a database restart.

1. Compile above C# code with fx. csc.exe.
2. Install MyODBC 3.51.10 or 3.51.12 (run the test once with both).
3. Run test application
4. When it says "kill connection now", use TCPView to close the=
connection.
5. Observe the difference in behaviour.....


Test results:
===============3D

MyODBC 3.51.10:
----------------
X:\>MySqlConnectTest.exe
Opening connection...
Ok. Kill database or connection now, then press Enter.
[ Note: killed connection here ]

Connection state 'Open' - executing query.
Connection state 'Open' - executing query.
Connection state 'Open' - executing query.
Connection state 'Open' - executing query.
Connection state 'Open' - executing query.

Done - press Enter.
----------------

Seems MyODBC 3.51.10 reconnects behind our back.
ConnectionState is (correctly) == ConnectionState.Open.

MyODBC 3.51.12:
----------------
X:\>MySqlConnectTest.exe
Opening connection...
Ok. Kill database or connection now, then press Enter.
[ Note: killed connection here ]

Connection state 'Open' - executing query.
Error: ERROR [HYT00] [MySQL][ODBC 3.51=
Driver][mysqld-4.1.9-standard-log]MySQL server has gone away

Connection state 'Open' - executing query.
Error: ERROR [HYT00] [MySQL][ODBC 3.51=
Driver][mysqld-4.1.9-standard-log]MySQL server has gone away

Connection state 'Open' - executing query.
Error: ERROR [HYT00] [MySQL][ODBC 3.51=
Driver][mysqld-4.1.9-standard-log]MySQL server has gone away

Connection state 'Open' - executing query.
Error: ERROR [HYT00] [MySQL][ODBC 3.51=
Driver][mysqld-4.1.9-standard-log]MySQL server has gone away

Connection state 'Open' - executing query.
Error: ERROR [HYT00] [MySQL][ODBC 3.51=
Driver][mysqld-4.1.9-standard-log]MySQL server has gone away

Done - press Enter.
----------------

Seems MyODBC 3.51.12 does _not_ reconnect behind our back.
ConnectionState is (incorrectly) still == ConnectionState.Open.


Workaround:
=============3D
We've implemented our own ConnectionState mechanism instead of=
using MyODBC's.


Proposed solution:
====================
I'm imagining that ConnectionState should say "Closed" when the=
connection has died behind our back.

The .Net documentation says:
"Calling the State property on an open connection increases=
application overhead because each such call results in a=
SQL_ATTR_CONNECTION_DEAD call to the underlying ODBC driver=
to determine if the connection is still valid."

If the assumption is not valid (which IMHO renders ConnectionState=
somewhat useless), the SQL_ATTR_CONNECTION_DEAD behaviour should=
at least be documented to be "weird".

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