EF 4.1 SQL Compact byte

我的查询遇到了一些性能瓶颈。每当我在实体中引入一个属性作为字节时，EF 4.1就会在使用它之前将其强制转换为int

var segmentQuery = workUnit.SegmentRepository.GetQuery()
                                             .Where(x => x.FileId == file.Id)
                                             .Where(x => x.StateValue == (byte)SegmentState.Unhandeled)
                                             .OrderBy(x => x.Index);

很好地翻译为：

SELECT 
....
FROM ( SELECT 
    [Extent1].[Id] AS [Id], 
    ...
    [Extent1].[StateValue] AS [StateValue]
    FROM [Segments] AS [Extent1]
    WHERE ([Extent1].[FileId] = @p__linq__0) AND (0 = [Extent1].[StateValue])
)  AS [Project1]
ORDER BY [Project1].[Index] ASC

然而，在上面的例子中：StateValue实际上是一个整数，这对于我的需求（4种不同的状态）来说太多了，但当将其更改为字节时，我得到：

SELECT ...
FROM ( SELECT 
    [Extent1].[Id] AS [Id], 
      ...
    [Extent1].[StateValue] AS [StateValue]
    FROM [Segments] AS [Extent1]
    WHERE ([Extent1].[FileId] = @p__linq__0) AND (0 = ( CAST( [Extent1].[StateValue] AS int)))
)  AS [Project1]
ORDER BY [Project1].[Index] ASC

由于该表一天可能包含超过100000行，因此State字段只占用1个字节是节省空间的（尽管幸运的是不是必需的），但是，更改为字节会扼杀我的查询。

我做错什么了吗？我能做什么吗？这个"问题"已知吗？

谢谢！

**更新**

[Flags]
public enum SegmentState : byte
{
    Unhandeled,
    Downloaded,
    Invalid,
    Assembled
}

在我的实体中：

/// <summary>
/// Dont use this, use SegmentState instead
/// </summary>
[Required]
public byte StateValue
{
    get { return _stateValue; }
    set { _stateValue = value; }
}
public SegmentState State
{
    get { return (SegmentState)StateValue; }
    set 
    {
        if (State != value)
        {
            StateValue = (byte)value;
            RaisePropertyChanged(StatePropertyName);
        }
    }
}