SubSonic：MySqlDataReader 关闭连接

发布于 2024-09-04 01:36:14 字数 517 浏览 5 评论 0原文

执行事务时遇到问题

我正在使用 SubSonic 2.1，并在使用SharedDbConnectionScope 和 TransactionScope 。问题是，在 obj.Save() 方法中，我得到一个“连接必须有效且打开”的异常，

我将问题跟踪到这一行：

// Loads a SubSonic ActiveRecord object
User user = new User(User.Columns.Username, "John Doe");

在 User 类的这个构造函数中，调用了一个方法“LoadParam”，该方法最终看起来

if (rdr != null)
    rdr.Close();

rdr.Close() 隐式关闭了我的连接，这在使用 AutomaticConnection 时很好。但在事务期间，关闭连接通常不是一个好主意:-)

我的问题是这是设计使然还是 MySqlDataReader 中的错误。

原文

I am using SubSonic 2.1 and entcountered a problem while executing a Transaction with

SharedDbConnectionScope and TransactionScope.
The problem is that in the obj.Save() method I get an "The connection must be valid and open" exception

I tracked down the problem to this line:

// Loads a SubSonic ActiveRecord object
User user = new User(User.Columns.Username, "John Doe");

in this Constructor of the User class a method "LoadParam" is called which eventually does

if (rdr != null)
    rdr.Close();

It looks like the rdr.Close() implicitly closes my connection which is fine when using the AutomaticConnection. But during a transaction it is usally not a good idea to close the connection :-)

My Question is if this is by design or if it's an error in the MySqlDataReader.

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穿透光 2024-09-11 01:36:14

这很棘手！
经过一番调试后，我在 SubSonic2 MySqlDataReader.cs 文件中发现了以下方法：

    public override IDataReader GetReader(QueryCommand qry)
    {
        AutomaticConnectionScope conn = new AutomaticConnectionScope(this);

        ...

        cmd.Connection = (MySqlConnection)conn.Connection;

        IDataReader rdr;

        try
        {
            rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
        }
        catch(MySqlException x)
        {
            conn.Dispose();
            throw x;
        }

        ...
    }

这是错误的，因为我使用的是 SharedDbConnection。在 SqlDataProvider 中它已经被修复，但对于 MySqlDataReader 还没有修复。

它应该看起来像这样：

        try
        {
            // if it is a shared connection, we shouldn't be telling the reader to close it when it is done
            rdr = conn .IsUsingSharedConnection ?
                      cmd.ExecuteReader() : 
                      cmd.ExecuteReader(CommandBehavior.CloseConnection);
        }
        catch (MySqlException)
        {
            // AutoConnectionScope will figure out what to do with the connection
            conn.Dispose();
            //rethrow retaining stack trace.
            throw;
        }

相当严重的错误，它使得事务中的查询变得不可能（我必须承认我以前从未需要过这个）。

That was tricky!
After a bit debugging I found the following method in the SubSonic2 MySqlDataReader.cs file:

    public override IDataReader GetReader(QueryCommand qry)
    {
        AutomaticConnectionScope conn = new AutomaticConnectionScope(this);

        ...

        cmd.Connection = (MySqlConnection)conn.Connection;

        IDataReader rdr;

        try
        {
            rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
        }
        catch(MySqlException x)
        {
            conn.Dispose();
            throw x;
        }

        ...
    }

Which is wrong since I am using a SharedDbConnection. In the SqlDataProvider it has been fixed already but not for MySqlDataReader.

It should look like this:

        try
        {
            // if it is a shared connection, we shouldn't be telling the reader to close it when it is done
            rdr = conn .IsUsingSharedConnection ?
                      cmd.ExecuteReader() : 
                      cmd.ExecuteReader(CommandBehavior.CloseConnection);
        }
        catch (MySqlException)
        {
            // AutoConnectionScope will figure out what to do with the connection
            conn.Dispose();
            //rethrow retaining stack trace.
            throw;
        }

Pretty heavy bug, it rendered Querying in a Transaction impossible (I must admit I never needed this before).

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