Unfortunately without quotes around 'anotherDataset' it looks like the text is mangled.  I was trying to get away from saying "The code generated for this is very inefficient" since it begs the question "why not fix it?"

How about..

The code generated for this is inefficient if 'anotherDataset' contains a large number of elements, and
may also cause a "Dataset too large to output to workunit" error.

A better way to recode the expression in this situation is this:...