"Race condition" on in-memory dictionary of streams about neventstore HOT 4 CLOSED

Perhaps I'm not quite following what you're saying. In looking at the code--OptimisticEventStore.cs line 98, I'm first pushing the "attempt" to storage. Following a successful commit of the attempt, I push the "commit" into the dispatch scheduler which one of the pipeline hooks.

I guess my question is, what is the exact problem you're experiencing and are you getting an exception?

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I think you should do precisely what you described in the future as well, but move the call to (:OptimisticEventStream).PopulateStream(StreamRevision+1, attempt.StreamRevision, new[]{ attempt }); in OptimisticEventStream.cs:152 to before the dispatch:

Now:

1. Commit changes to persistence engine (OK!)
2. (OptimisticPipelineHook.PostCommit)
3. DispatchSchedulerPipelineHook.PostCommit (too soon)
4. OptimisticEventStream.PopulateStream

To:

1. Commit changes to persistence engine (OK!)
2. (OptimisticPipelineHook.PostCommit)
3. OptimisticEventStream.PopulateStream
4. DispatchSchedulerPipelineHook.PostCommit

The problem is that I'm using request-reply right now, the reply being the event. When I get that one event, I have a command I wish to send directly afterwards, which actually leads to this 'observable' execution:

1. Commit changes to persistence engine (OK!) [thread a]
2. (OptimisticPipelineHook.PostCommit) [thread a]
3. DispatchSchedulerPipelineHook.PostCommit (too soon) [thread a]
4. Receive new command in [thread b]
5. Thread reads OptimisticEventStream from dictionary Guid->Stream, finds this particular stream. Stream is yet to be populated, so it contains no events even though both dispatch has been sent and database written. [thread b]
6. OptimisticEventStream.PopulateStream [thread a]

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Sample, ugly fix: https://github.com/haf/EventStore/compare/feature%2Fmemstream

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After researching exactly why this is happening, it's because the OptimisticEvenStream is designed to be single threaded, much like NHibernate's ISession or LINQ to SQL's DataContext. You'll notice this in the XML code comments for IEventStream.cs. The behavior of sharing across threads is undefined, which is exactly what you're experiencing.

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