MySQL Bugs: #25726: MySqlConnection throws NullReferenceException and ArgumentNullException

Bug #25726	MySqlConnection throws NullReferenceException and ArgumentNullException
Submitted:	19 Jan 2007 21:46	Modified:	31 Jan 2007 16:06
Reporter:	Robert Hood	Email Updates:
Status:	Closed	Impact on me:	None
Category:	Connector / NET	Severity:	S3 (Non-critical)
Version:	5.0.3	OS:	Windows (Windows XP pro)
Assigned to:		CPU Architecture:	Any
Tags:	5.0.3, MySql Connector

Description:
The MySqlConnection throws the following exception when connecting to a 4.1.7 MySql Server:

   at MySql.Data.MySqlClient.NativeDriver.get_SupportsBatch()
   at MySql.Data.MySqlClient.Statement.TokenizeSql(String sql)
   at MySql.Data.MySqlClient.Statement.BindParameters()
   at MySql.Data.MySqlClient.PreparableStatement.Execute(MySqlParameterCollection parameters)
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader()
   at MySql.Data.MySqlClient.Driver.Configure(MySqlConnection connection)
   at MySql.Data.MySqlClient.NativeDriver.Configure(MySqlConnection connection)
   at MySql.Data.MySqlClient.MySqlConnection.Open()
   at DataTest.DataAccess.GetMySqlData(String serverName) in C:\Documents and Settings\a339144\Desktop\DataTest\DataAccess.cs:line 53

It also throws the following IndexOutOfRangeException when connecting to a 4.1.0-alpha MySql Server

   at MySql.Data.MySqlClient.MySqlDataReader.GetOrdinal(String name)
   at MySql.Data.MySqlClient.MySqlDataReader.get_Item(String name)
   at MySql.Data.MySqlClient.Driver.LoadCharacterSets()
   at MySql.Data.MySqlClient.Driver.Configure(MySqlConnection connection)
   at MySql.Data.MySqlClient.NativeDriver.Configure(MySqlConnection connection)
   at MySql.Data.MySqlClient.MySqlConnection.Open()
   at DataTest.DataAccess.GetMySqlData(String serverName) in C:\Documents and Settings\a339144\Desktop\DataTest\DataAccess.cs:line 53

How to repeat:
Open a connection to a MySql Database that is older than 4.1.9.  Different server versions seem to cause the connector to throw different exceptions.  We cannot immediately upgrade our servers as downtime is very costly to our plants.

Suggested fix:
Test the connector against a larger majority of past versions of MySql.  Our current range of server versions affected by the bug include: 
4.1.0-alpha
4.1.1-alpha
4.1.1-alpha-log
4.1.0-alpha-log
4.1.3-beta
4.1.7
4.1.9

Hi Robert and thanks for your problem report.

Verified as described by reporter with mysqld-nt.exe started with --standalone --console:
Version: '4.1.7-nt'  socket: ''  port: 3306  Source distribution
on WinXP Pro SP2 localhost using NET FW 2.0 with latest c/NET sources.

Error is in NativeDriver.cs, line 75:
public override bool SupportsBatch
{
	get
	{
		if ((Flags & ClientFlags.MULTI_STATEMENTS) != 0)
		{
			if (version.isAtLeast(4, 1, 0) && !version.isAtLeast(4, 1, 10))
			{
				if (serverProps["query_cache_type"].Equals("ON") &&
					!serverProps["query_cache_size"].Equals("0")) return false;
			}
			return true;
		}
		return false;
	}
}

For now, please use "allow batch=False" connect option as a workaround.

The work around works for all version we currently work with, with the exception of 4.1.0-alpha. When connecting to this version of MySql, I am receiving an IndexOutOfRangeException.  Thanks for your help so far.  If you can identify this error and a work-around, we will be all set to deploy Connector 5.0.3

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/18642

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/18643

Fixed issue with 4.1.7 in 1.0.9 and 5.0.4.  Will not spend time analyzing problems with alpha builds of the server.

A note has been added to the 1.0.9 and 5.0.4 changelogs.