Protobuf.net例外 - 超时在检查元数据 [英] Protobuf.net Exception - Timeout while inspecting metadata

问题描述

我的有时的尝试deserialise使用protobuf.net对象时，收到以下异常。我很惊讶，因为我从来没有比单个线程deserialising在同一时间同一对象和protobuf.net源似乎并没有使用任何静态对象的deserialising更多。该例外情况提出一个解决方案，但我不能确定如何实现这样会欢迎一个例子

I am sometimes receiving the following exception when attempting to deserialise an object using protobuf.net. I'm surprised as I never have more than a single thread deserialising the same object at the same time and the protobuf.net source does not seem to use any static objects for deserialising. The exception does suggest a solution but I am unsure as to how to implement so would welcome an example.

Base Exception Type:
System.TimeoutException: Timeout while inspecting metadata; this may indicate a deadlock. This can often be avoided by preparing necessary serializers during application initialization, rather than allowing multiple threads to perform the initial metadata inspection
at ProtoBuf.Meta.RuntimeTypeModel.TakeLock(Boolean& lockTaken)
at ProtoBuf.Meta.RuntimeTypeModel.FindOrAddAuto(Type type, Boolean demand, Boolean addWithContractOnly, Boolean addEvenIfAutoDisabled)
at ProtoBuf.Meta.RuntimeTypeModel.GetKey(Type type, Boolean demand, Boolean getBaseKey)

Inner Exception Type:
System.TimeoutException: Timeout while inspecting metadata; this may indicate a deadlock. This can often be avoided by preparing necessary serializers during application initialization, rather than allowing multiple threads to perform the initial metadata inspection
at ProtoBuf.Meta.RuntimeTypeModel.TakeLock(Boolean& lockTaken)
at ProtoBuf.Meta.RuntimeTypeModel.FindOrAddAuto(Type type, Boolean demand, Boolean addWithContractOnly, Boolean addEvenIfAutoDisabled)
at ProtoBuf.Meta.RuntimeTypeModel.GetKey(Type type, Boolean demand, Boolean getBaseKey)

Stack Trace: 
at ProtoBuf.Meta.RuntimeTypeModel.GetKey(Type type, Boolean demand, Boolean getBaseKey)
at ProtoBuf.Meta.TypeModel.GetKey(Type& type)
at ProtoBuf.Meta.TypeModel.Deserialize(Stream source, Object value, Type type)

问候，
马克

编辑补充：所以我定义我serialisable对象：

edit to add: I define my serialisable objects thus:

[ProtoContract]
public class Job
{
    [ProtoMember(1)]
    public long JobId { get; private set; } 
}

这将是我很难方便地调用PrepareSerialiser上的每一个我serialisable对象，因为我有不同的命名空间很多。不过想着它是什么，如果protobuf的被要求deserialise相同类型的两个对象发生的，一类是以前没有见过，在完全相同的时间？

It would be difficult for me to easily call PrepareSerialiser on each one of my serialisable objects as I have many in different namespaces. However thinking about it what happens if protobuf is asked to deserialise two objects of the same type, a type it has not seen before, at exactly the same time?

推荐答案

RuntimeTypeModel.Default（默认模式）是静态的，支撑静态序列化器类（重的评价是，没有任何静态）。尽管增加这个检查，由于偏执狂，我的从不看到这个错误引发。我绝对乐意看到将瑞普这样的例子。你确定你是不是线程？如果没有线程，我只能纳闷：是类型模型实在的真正的大

RuntimeTypeModel.Default (the default model) is static, and underpins the static Serializer class (re the comment that there wasn't any static state). Despite adding this check due to paranoia, I have never seen this error raised. I would absolutely love to see an example that will repro this. Are you sure you aren't threading? If not for threading, I can only wonder: is the type-model really really big?

事实上，即使有许多线程击中它积极在启动时（即在这里计算器），它很乖。由于错误信息提示，您可以尝试应用程序，启动过程中调用Serializer.PrepareSerializer，这将预先初始化的一切，避免任何线程的担忧。

Indeed, even with many threads hitting it aggressively at startup (i.e. here on stackoverflow) it is well behaved. As the error message hints, you might try calling Serializer.PrepareSerializer during app-startup, which will pre-initialize everything, avoiding any threading concerns.

但是，嘿！至少它没有发生死锁！

But hey! At least it didn't deadlock!

在这里奇怪的事情，虽然是它的的还是的不该 T为的可能的死锁 - 它故意用粗锁，以避免需要锁定顺序问题。再次 - 我真的很想看到一个样本

The odd thing here, though, is that it still shouldn't be possible to deadlock - it deliberately uses a coarse lock to avoid issues from the order it takes lock. Again - I'd really love to see a sample.

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