Event Store cannot write to soft deleted streams

Question

To clearify: This question is about Greg Young's Event Store.

I tried to soft delete a stream which contained 2 events:

var slice = con.ReadStreamEventsBackwardAsync(streamName, 0, 1, resolveLinkTos: true).Result;
es.DeleteStreamAsync(streamName, slice.LastEventNumber, hardDelete: false).Wait();

This call was successful and investigating the store revealed a new metadata event. This event was of type $metadata and contained:

{
  "$tb": 9223372036854775807
}

$tb stands for "truncate before" and is described in Deleting streams and events. The documentation says:

When you delete a stream, its TruncateBefore or $tb is set to the streams current last event number.

Which (as you can see in the json above) is not the case. Truncate before is set to long.MaxVaue. Although this seems to be bad behaviour it is not the actual problem. The issue is that I cannot write to the stream anymore. Invoking the following snipped completes successfully but does not append any event to the stream:

await es.AppendToStreamAsync(persistenceId, expectedVersion < 0 ? ExpectedVersion.NoStream : expectedVersion, events);

In the snipped above, expectedVersion is set to -1. The metadata of the soft deleted stream says:

Stream is deleted: False
Meta Stream version: 0
Truncate before: 9223372036854775807
Max count:
Max age:

And reading the slice from the last event of the stream reveales:

Last Event number: 1
Next Event number: -1
Status: StreamNotFound

Has anybody encountered the same issue and might have found a solution which allows continuing appending events to deleted streams?

Answer 1

我通过请求请求收到了一些有价值的信息。 首先，即使事件存储在当前时间点上的行为与文档中所描述的都不一样，但其行为仍正确。

我们从持久性ID和序列号生成了确定性Guid。除非您根据流中的事件数确定序列号，否则不会有问题。软删除的流没有返回任何导致新事件的序列号为0的事件，因此我们生成了与流中第一个（但已删除）事件相同的事件ID。然后事件存储继续进行，并忽略了新事件，因为（基于生成的事件ID）已存储并删除了该新事件。

解决方案是从StreamEventSlice.LastEventNumber而不是从事件存储返回的事件数中获取当前序列号。