- This is for full aggregation with "Detect Deleted" checked in its task definition. For Delta aggregation, "Detect Deleted" will be ignored;

- The delete phase always happens after the primary aggregate phase during a aggregation;
- In the primary aggregate phase, no matter the optimization option is enabled or not, accounts that exist in source will always have their last refresh timestamp updated;

- When the aggregation starts, it gets the current timestamp ( Date startTimestamp = new Date() ) and when it gets to the delete phase, it does the comparison as below:
- select *
- from spt_link
- where (last_refresh < startTimestamp or last_refresh isnull) and
- created < startTimestamp and
- application = "source app";
Hope this helps with your understanding of how should-be-deleted accounts are detected.
For more details on aggregation workflow, please see Aggregation Data Flow.pdf