Avro（微软）派生类型成员序列化丢失

Question

我正在评估微软实现Avro的性能，起初我以为我得到惊人的性能，直到我意识到它只是没有序列化整个消息;-)

下面有一个用[DataContract]（基础和两个派生类型）装饰的简单消息层次结构。所有成员都使用[DataMember]属性进行装饰。我从基本消息类型创建序列化程序并序列化派生消息列表，但它似乎只序列化/反序列化基类成员。结果中缺少所有派生消息成员。

我错过了什么吗？我的应用程序需要混合消息类型。

FWIW我没有看到二进制文件中的第二个派生类型的任何字符串，所以我怀疑派生类型成员没有被序列化。

Thanks, Greg 


class Program 
{ 
    [DataContract(Name = "SideType", Namespace = "AvroMessage")] 
    public enum EventType 
    { 
     Unknown = 0, 
     One = 1, 
     Two = 2 
    } 

    [DataContract(Name = "MessageBase", Namespace = "AvroMessage")] 
    public class MessageBase 
    { 
     [DataMember(Name = "Subtype")] 
     public string Subtype; 

     [DataMember(Name = "Timestamp")] 
     public DateTime Timestamp; 

     [DataMember(Name = "GroupName")] 
     public string GroupName; 

     public override bool Equals(object obj) 
     { 
      MessageBase other = obj as MessageBase; 
      if (other == null) return false; 

      return Subtype == other.Subtype && 
        Timestamp == other.Timestamp && 
        GroupName == other.GroupName; 
     } 
    } 

    [DataContract(Name = "SubMessage1", Namespace = "AvroMessage")] 
    public class SubMessage1 : MessageBase 
    { 
     [DataMember(Name = "Volume")] 
     public int Volume; 

     [DataMember(Name = "Count")] 
     public int Count; 

     [DataMember(Name = "DetectedSide")] 
     public EventType Event; 

     public override bool Equals(object obj) 
     { 
      SubMessage1 other = obj as SubMessage1; 
      if (other == null) return false; 

      return Subtype == other.Subtype && 
        Timestamp == other.Timestamp && 
        GroupName == other.GroupName && 
        Event == other.Event && 
        Volume == other.Volume && 
        Count == other.Count; 
     } 
    } 

    [DataContract(Name = "SubMessage2", Namespace = "AvroMessage")] 
    public class SubMessage2 : MessageBase 
    { 
     [DataMember(Name = "Name1")] 
     public string Name1; 

     [DataMember(Name = "Volume1")] 
     public int Volume1; 

     [DataMember(Name = "Name2")] 
     public string Name2; 

     [DataMember(Name = "Volume2")] 
     public int Volume2; 

     [DataMember(Name = "PriceMove")] 
     public double PriceMove; 

     public override bool Equals(object obj) 
     { 
      SubMessage2 other = obj as SubMessage2; 
      if (other == null) return false; 

      return Subtype == other.Subtype && 
        Timestamp == other.Timestamp && 
        GroupName == other.GroupName && 
        Volume1 == other.Volume1 && 
        Name1 == other.Name1 && 
        Volume2 == other.Volume2 && 
        Name2 == other.Name2 && 
        PriceMove == other.PriceMove; 
     } 
    } 

    public class MessageFactory 
    { 
     public static IEnumerable<MessageBase> CreateMessages(int number) 
     { 
      Random ran = new Random(); 

      List<MessageBase> retval = new List<MessageBase>(); 
      for (int i = 0; i < number; i++) 
      { 
       if (ran.Next(2) == 0) 
       { 
        SubMessage1 sub1 = new SubMessage1(); 
        sub1.Timestamp = DateTime.Now; 
        sub1.GroupName = "Group" + DateTime.Now.Millisecond.ToString(); 
        sub1.Subtype = "SubMessag1"; 
        sub1.Volume = ran.Next(10000); 
        sub1.Count = ran.Next(100); 
        if (ran.Next(2) == 0) 
        { 
         sub1.Event = EventType.One; 
        } 
        else 
        { 
         sub1.Event = EventType.Two; 
        } 
        retval.Add(sub1); 
       } 
       else 
       { 
        SubMessage2 sub2 = new SubMessage2(); 
        sub2.Timestamp = DateTime.Now; 
        sub2.GroupName = "Group" + DateTime.Now.Millisecond.ToString(); 
        sub2.Subtype = "SubMessag2"; 
        sub2.Volume1 = ran.Next(1000); 
        sub2.PriceMove = ran.NextDouble() * 100 - 50; 
        sub2.Volume2 = ran.Next(1000); 
        sub2.Name1 = "Contract" + (DateTime.Now.Millisecond + ran.Next(5)).ToString(); 
        sub2.Name2 = "Contract" + DateTime.Now.Millisecond.ToString(); 
        retval.Add(sub2); 
       } 
      } 
      return retval; 
     } 

    } 

    public static void TestAvro(int count) 
    { 
     bool correct = false; 
     long serTicks = 0; 
     long deserTicks = 0; 

     Stopwatch sw = new Stopwatch(); 
     sw.Reset(); 

     var serializer = Microsoft.Hadoop.Avro.AvroSerializer.Create<MessageBase>(); 
     MessageBase[] messages = new MessageBase[count]; 
     using (var file = File.Create(@"C:\test_avro.bin")) 
     { 
      int i = 0; 
      foreach (var message in MessageFactory.CreateMessages(count)) 
      { 
       messages[i++] = message; 
       sw.Start(); 
       serializer.Serialize(file, message); 
       sw.Stop(); 
      } 
     } 

     serTicks = sw.ElapsedTicks; 
     sw.Reset(); 

     List<int> badMessages = new List<int>(); 
     using (var file = File.OpenRead(@"C:\test_avro.bin")) 
     { 
      for (int i = 0; i < count; i++) 
      { 
       sw.Start(); 
       MessageBase message = serializer.Deserialize(file); 
       sw.Stop(); 

       SubMessage1 m1 = message as SubMessage1; 
       SubMessage2 m2 = message as SubMessage2; 

       bool areNull = (m1 == null) && (m2 == null); // Always true 

       if (!messages[i].Equals(message)) badMessages.Add(i); 
      } 
     } 

     deserTicks = sw.ElapsedTicks; 
     correct = badMessages.Count == 0; 

     long size = (new FileInfo(@"C:\test_proto.bin")).Length; 

     Console.WriteLine(String.Format("Correct: {0}, Time Out: {1}, , Time In: {2}, , Size: {3}", correct, serTicks, deserTicks, size)); 
    } 

    static void Main(string[] args) 
    { 
     TestAvro(10000); 
     Console.ReadLine(); 
    } 
} 

Answer 1

我不好 - 我忘了基类的KnownType属性，每个派生类型都有一个。它适用于包含属性的情况。