Concurrent appends to same stream and ExpectedVersion.Any on Postgres throws WrongExpectedVersion

[stoft]

Concurrent appends to same stream and ExpectedVersion.Any on Postgres throws WrongExpectedVersion

[roetlich]

We did add that C# example by the way: #480
The CI passed on that one, but the test failed for postgres.

[yreynhout]

One of the first things I spot here is that you're not using 1 instance of SqlStreamStore (which is preferred in the same process space). If the idea is to test with separate instances (is this what you mean by dedicated connections?) then at least make sure you dispose each instance when you're done. That said, it should not make a difference for the behaviour you observe.

Looking at https://github.com/SQLStreamStore/SQLStreamStore/blob/master/src/SqlStreamStore.Postgres/PostgresStreamStore.Append.cs#L13 it's obvious that the postgres implementation does not special case ExpectedVersion.Any thus being more likely to run into the retry limit IF the underlying sql causes it. For that we'd have to dig into https://github.com/SQLStreamStore/SQLStreamStore/blob/master/src/SqlStreamStore.Postgres/PgSqlScripts/AppendToStream.sql and deeper (which does cater for ExpectedVersion.Any).

The simplest thing to do is add a test to the test suite which mimics your test above and see if we run into the same trouble. If we do, we have a reproducible scenario to work with.

[stoft]

@yreynhout yes, that's what I meant by dedicated connections. We've tried both setups with the same result.

I'll try to cobble together a test in C# next week. 🙂