SSIS 2008 - Multicast Transformation

Multicast Transformation:

Simplest transformation of SSIS. As per the name Multicast transformation creates multiple copies of provided dataset. This transformation does not support Error Routing. This transformation has one input and multiple outputs.

Below screen shot shows, multicast transformation routing all 9 source records to all the 5 flows:

Difference between Conditional Split and Multicast:

Conditional split, routes the data to different flows based on the Condition specified, if none of the condition matches, then in that case it routes that particular row to default output. Due to this a given record gets routed to only one flow. Whereas in case of multicast, we don’t specify any condition which results in routing a record to all available outputs.

Uses of Multicast Transformation:
Let's say we have a DFT which reads the data from Staging table and loads it into datawarehouse performing a 'Type 2 SCD', which has a custom logging been implemented in which we are tracking how records got inserted(new records) and how many got updated. For this DFT, in insert flow just before destination a multicast can be placed which will route one flow to destination for insertion, and other flow can be mapped to Row Count transformation which we will assign that count to a pre-defined variable which can further be used for inserting that row count value in logging table. Same logic can be implemented for Update flow.