I created a migration using migrate and I am importing commerce products which contain several multivalue field collections which can be nested. For importing 50 products 47322 queries are being executed which make up most of the time of my migration script. field_attach_update is called 742 times and field_attach_insert 518 times. Calling field_attach_update more than field_attach_insert is not really necessary because all entities are new. Any suggestions? Could we optimize this somehow?