Different results when reading from Stream versus reading AllEventsForward

EventStoreDB
1

I have defined the following projection in my Event Store:
fromAll()

.when({

    $any: function (s, e) {

        if (e.eventType.indexOf('$') !== 0 && 

            e.streamId.indexOf('$') !== 0 )

            linkTo ('Non-SystemEvents', e);

    }    

})

When reading from the resulting stream using the following method, I get the correct number of events back, but they do not deserialize properly (I use the method in a loop with sliceSizes of 1000).

   public ResolvedEvent[] PerformReadFromStream(string streamName, int startPosition, int sliceSize, out int endPosition, out bool isEndOfStream)

    {

        EnsureConnection();

        var resolvedEvents = new List<ResolvedEvent>();

        var nextPosition = startPosition;

        var slice = eventStoreConnection.ReadStreamEventsForward(streamName, nextPosition, sliceSize, false);

        resolvedEvents.AddRange(slice.Events.Where(EventRequirements));

        endPosition = slice.NextEventNumber;

        isEndOfStream = slice.IsEndOfStream;

        return resolvedEvents.ToArray();

    }

The ResolvedEvent.Event.EventType is “$>” for all of these stream events, which looks suspciously like a pointer to me.

However, when I change the code to read using ReadAllEventsForward, the ResolvedEvents parse just fine.

    public ResolvedEvent[] PerformRead(Position startPosition, int sliceSize, out Position endPosition, out bool isEndOfStream)

    {

        EnsureConnection();

        var resolvedEvents = new List<ResolvedEvent>();

        var nextPosition = startPosition;

        var slice = eventStoreConnection.ReadAllEventsForward(nextPosition, sliceSize, false);

        resolvedEvents.AddRange(slice.Events.Where(EventRequirements));           

        endPosition = slice.NextPosition;

        isEndOfStream = slice.IsEndOfStream;

        return resolvedEvents.ToArray();

    }

I have built this projection on two different EventStores (one with 3 million events, one with 7 million events), and I get the same issue in both places. Is there something obviously wrong with my approach?

2

You need to skip any event where EventType.StartsWith("$")

3

You can resolve the pointers in the Client API, the reading methods all have “resolveLinkTos” as one of the options, see https://github.com/EventStore/EventStore/blob/dev/src/EventStore.ClientAPI/IEventStoreConnection.cs#L164 .
Setting this to true will populate the link and the event.

Does this do what you’re looking for?

James

4

He probably should not do this if he is reading from the $all stream though.

5

Herpy derp, disregard my last email.

6

This solved the problem. Guess I should have read the parameters a bit closer.

Thanks much!

Kerry