also set the maximum degree of parallelism to 1 in order to ensure a serial plan. This, however, is overkill – the optimizer will do
https://sqlsunday.com/2014/11/16/parallel-execution-part-2/comment-page-1/#comment-1635
the LEAD() function uses the Sequence Project operator, which means it won’t execute in a parallel zone in your execution
https://sqlsunday.com/2014/11/16/parallel-execution-part-2/comment-page-1/#comment-1624
parts of this series, we’ve looked at how parallelism works, how you can control it, and how it affects your query (and server) performance in different environments. In this, the third part, ...
https://sqlsunday.com/2014/11/16/parallel-execution-part-2/comment-page-1/#comment-1580