System.InvalidCastException: Cannot convert CLR type to JOIN type

Question

We are attempting to perform a Left Anti-Semi Join in Stream Insight using a custom payload type, called CRB. It contains only primitive fields (no lists or anything special). We are seeing the InvalidCastException when attempting to do this. If we remove the LASJ, everything works fine. Here is the LASJ code.

var inputStream = this.InputQuery.ToStream<CRB>();

var filter =
	from record in inputStream
	where record.AppliedJobCode == 1556
	where ( 
		from right in inputStream
		where right.AppliedJobCode == 1155
		select right
	).IsEmpty()
	select record;

Once again, if we remove the LASJ (the second where clause), there are no problems with the filter. Any help or guidance is most appreciated.

Thanks,

Dave

Answer 1

Without knowing the actual data types at play here, I'm kind of shooting in the dark. I would try decomposing the filter statement and doing a projection on the right stream so you can end up with an event to event comparison like the following:

var inputStream = this.InputQuery.ToStream<CRB>();

var leftStream = inputStream.Where(e => e.AppliedJobCode == 1556);
var rightStream = from e in inputStream
			where e.AppliedJobCode == 1155
			select new CRB
			{
				AppliedJobCode = 1556
				// project other fields here
			};
			
var filter = from left in leftStream
			 where (
			 			from right in rightStream
						where left.AppliedJobCode == right.AppliedJobCode
						select right
					).IsEmpty();
			select left;

Answer 2

I did a quick mock-up of the query and types in LinqPad and ran it with no problem. Can you take a look and, perhaps, modify to better illustrate your case?

void Main()
{
	Func<int, DateTimeOffset> t = (m) => new DateTimeOffset(2011, 1, 11, 8, 0, 0, TimeSpan.Zero).AddMinutes(m);
	var values = new[]{
		new {Name="App 1", AppliedJobCode=1155, Timestamp = t(0)},
		new {Name="App 2", AppliedJobCode=1156, Timestamp = t(0)}, 
		new {Name="App 3", AppliedJobCode=1155, Timestamp =t(1)},
		new {Name="App 4", AppliedJobCode = 1155, Timestamp=t(4)}
	};
	var crbStream = values.ToPointStream(Application, 
		e => PointEvent.CreateInsert(e.Timestamp, new CRB(){Name = e.Name, AppliedJobCode = e.AppliedJobCode}), 
		new AdvanceTimeSettings(
		new AdvanceTimeGenerationSettings(TimeSpan.FromSeconds(1), TimeSpan.FromTicks(1)), 
		null, AdvanceTimePolicy.Drop));
		
	var lasj = from i in crbStream 
				where i.AppliedJobCode == 1155
				where (from j in crbStream where j.AppliedJobCode == 1156 select j).IsEmpty()
				select i; 
				
	lasj.ToPointEnumerable().Dump(); 
		
}
// Define other methods and classes here
public class CRB{
	public int AppliedJobCode { get; set; }
	public string Name { get; set; }
}

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DevBiker (aka J Sawyer)
Microsoft MVP - Sql Server (StreamInsight)

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Answer 3

Thanks all for the suggestions.  We are still working through this.  I'll take each reply one a time here.

TXPower125, we tried that in our app, to but still have the InvalidCastException when the filter expression is being run.  The exception is exactly the same, except for the number following the Join name (before it was 1.4, now it is 1.2). I'm not sure if that makes a difference.

DevBiker, our original example worked in linqpad, which leads me to believe the issue lies somewhere in the input/output adapter type setup. Obviously, this hasn't been confirmed.  However, we are using the Reflection namespace's MakeGeneric methods to instantiate the items we need.

Our next step is to temporarily remove the generic typing methods and have all types hard-coded. Hopefully, that will lead us to a solution. I'll post back here once I have more information.

Thanks again!