Was having some issues loading large data sets on initial load (before incremental update kicks in). Thought the Advanced option in the Data Source setting would assist in limiting the data size extracted from the source. I set the Record Fetch Size to 200,000 records. Then rebuilt the reflections. The reflection job is still attempting to pull in ALL of the millions of records, not just 200,000 at a time.
How is this feature suppose to behave?
As a side note. Be careful, this feature deletes all of the current reflections setup on the direct source tables (however not any of the virtual queries, thank goodness).