Merge Join - No Output Rows

Hi,

I have a problem with a Merge Join providing no output (when it should have 1890 rows). My Data Flow Task has 4 OLE Data Sources, 3 Multicasts, and 1 OLE Data Destination. I am experiencing the problem near the end of my data flow where two Multicasts create two parallel flows of data (see Level 1 below). I have two Merge Joins which join one leg from each multicast with a leg from the other multicast (see Level 2 below). Then the two remaining legs use a Merge to get my destination output (see Level 3 below).

I am experiencing my problem with the Merge Join (input A2, B2) --> (output C2) transformation. The Merge Join providing output C1 appropriately outputs 1890 rows, but C2 outputs 0 rows. Both Merge Joins are identical. The data is identically sorted prior to entering the problematic Merge Join and a DataViewer (Grid) verified that the data is appropriately entering in. Merge Join (input A2, B2) --> (output C2) has 667 rows as input A2 and 1890 rows as input B2 (using an inner join, just like the other merge join), but C2 baffles me with 0 rows of output (when it too should have 1890). I receive no Ouput errors and the execution completes showing all green.

Level 1
Multicast (output A1, A2) [667 rows]
Multicast (ouput B1, B2) [1890 rows]


Level 2
Merge Join (input A1, B1) --> (output C1) [1890 rows]
Merge Join (input A2, B2) --> (output C2) [0 rows]

Level 3
Merge (input C1, C2) --> (output D1) [1890 rows]*


I read about mysterious behavior with Merge Joins and have attempted modifying my EngineThreads property to values between 2 and 10, with no luck. Any help/ideas would be appreciated.

Thanks,

Devin

* Should be 3780 rows