What is the underlying behavior for deletes during a historical re-sync?
After a historical re-sync, records that still exist in the source will be marked as
_fivetran_deleted = false in the warehouse, and all records that have been deleted from the source will be marked as s
_fivetran_deleted = true in the warehouse.
When historical sync is triggered all existing data in the warehouse is soft deleted, meaning they will be marked as
_fivetran_deleted = true.
For the new import being done, the records (irrespective of whether they had already existed in the warehouse or not) will be marked as
_fivetran_deleted = false. These will be net new entries into the warehouse.
The idea is that at a given point in time there should only be one row with a specific Primary Key with
_fivetran_deleted = false in the warehouse.