In reply to Jim Leone.

Hi Jim, thank you for your insightful comments! Yes you are correct that the data must be loaded in memory for CAS to process it. I will work on clarifying the language. You are right that the differences between a caslib and a traditional SAS library can be tricky to explain. Great idea for a future post.

Regarding the data step merge, I have done a lot of experimentation with it since I wrote this post and I am seeing that as long as you are merging on a unique key, the results are predictable and as expected. The bonus is that you don't have to sort (and really, can't sort) the data in CAS. In fact, I am finding the data step merge to be much faster compared to FedSQL join. I will update my reply to Ashok's comment because I think it is misleading. Thank you for pointing it out.