The Multicast Transformation

Fig 1: The Multicast Transformation

In this post I will be covering the Multicast Transformation. The sample package can be foundĀ here for 2005 and guidelines on use are here.

What does the Multicast transformation do?

The Multicast creates as many copies of the entire data flow as you want. There is very little configuration available – all you can do is add a Name and Description for each output once you have created it by dragging one to a transformation or destination.

According to Jamie Thompson @ SSIS Junkie (in a post about a bug fixed in 2005 SP2), it doesn’t actually create a new data buffer so it doesn’t double up the memory usage – at least until the data is changed. But be aware if Multicasting large data sets you put yourself at risk of consuming a lot of memory.

When would you use the Multicast transformation?

The main use is where you need to perform different operations on the same set of data – the example quoted on MSDN which matches my experience is where you send the data to one destination and a summarised version to another. Another use i’ve had was directing slightly different versions same set of source data to different file locations.

MSDN Documentation for the Unpivot Transformation can be found here for 2008 and here for 2005.

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