MySQL Bugs: #109331: MySQL Connector fails to connect to MariaDB 10.10.2

Bug #109331	MySQL Connector fails to connect to MariaDB 10.10.2
Submitted:	11 Dec 2022 5:39	Modified:	22 Dec 2022 12:41
Reporter:	Ivaylo Ivanov	Email Updates:
Status:	Unsupported	Impact on me:	None
Category:	Connector / NET	Severity:	S2 (Serious)
Version:	8.0.31	OS:	Windows
Assigned to:		CPU Architecture:	Any
Tags:	Connector/Net, MariaDB

Description:
When connecting to MariaDB 10.10.2 MySqlConnection.Open() throws exception

System.InvalidCastException: Object cannot be cast from DBNull to other types.
   at System.DBNull.System.IConvertible.ToInt32(IFormatProvider provider)
   at System.Convert.ToInt32(Object value, IFormatProvider provider)
   at MySql.Data.MySqlClient.Driver.LoadCharacterSets(MySqlConnection connection)
   at MySql.Data.MySqlClient.Driver.Configure(MySqlConnection connection)
   at MySql.Data.MySqlClient.MySqlConnection.Open()
   at ...

Using the latest Connector/NET 8.0.31 and MariaDB 10.10.2
but affect all versions of Connector/NET, likely caused by MariaDB

Starting with MariaDB version 10.10.1 the Information_Schema.COLLATIONS
table includes records with null ID   
https://jira.mariadb.org/browse/MDEV-27009

MySqlConnection.Open() calls Driver.Configure()
Driver.Configure() calls Driver.LoadCharacterSets()
Driver.LoadCharacterSets() executes 'SHOW COLLATION' 
 expecting the ID to be an integer:

  MySqlCommand cmd = new MySqlCommand("SHOW COLLATION", connection);
  // now we load all the currently active collations
  try
  {
    using (MySqlDataReader reader = cmd.ExecuteReader())
    {
      CharacterSets = new Dictionary<int, string>();
      while (reader.Read())
      {
        CharacterSets[ Convert.ToInt32(reader["id"],
                       NumberFormatInfo.InvariantInfo)] =
          reader.GetString(reader.GetOrdinal("charset"));
      }
    }
    ...

How to repeat:

Try to open connection to MariaDB version 10.10.1 or later

Suggested fix:

Handle 'SHOW COLLATION' results that have null id

Hi Ivaylo, 

MySQL and MariaDB are diverging products and compatibility is no longer guaranteed and is not a common objective of both projects. 
MariaDB is not a drop-in replacement of MySQL anymore.

Storage engines, protocol, etc.. all are going in different directions.

Therefore MySQL Connectors are developed with MySQL Server (Community, Enterprise) focus.

Regards,

Hi,
Same issue for me.

I just replace the package MySql.Data by MySqlConnector (https://www.nuget.org/packages/MySqlConnector/). And the connection was back again.

Hello Ivaylo Ivanov,

Thank you for the bug report.
As Frederic explained, this is an unsupported issue. Our development is totally focused on MySQL Server.

Regards,
Ashwini Patil

Bug #113092 marked as duplicate of this one.