too much db queries in admin page

my admin page takes a long time to load, I started to work with debug_toolbar and I have some questions.
this is what I see when I open my product model:

103 queries it’s too much!
my admin:

class ProductAdmin(admin.ModelAdmin): # in product/
list_display = (..., 'total_amount')
    def get_queryset(self, request):
         qs = Product.objects.select_related('category').prefetch_related('images','stocks')
         return qs

class Stock(models.Model): # in stock/
    class Meta():
        verbose_name = _('Stock')
        verbose_name_plural = _('Stocks')
        default_related_name = 'stocks'

def total_amount(self, *args, **kwargs): # in product/ - class Product(models.Model)
        from stock.models import Stock
        from django.db.models import Sum
        #stocks = Stock.objects.filter(product=self)
        stocks = self.stocks
        res = stocks.aggregate(Sum('amount'))
        return res['amount__sum']
    total_amount.short_description = _("total stock at us")
  1. why does I still do a query to the database for every stock to aggregate the sum after I prefetched it?
    I can that I have 91 similar queries
  2. should I call get_queryset super? if so, in what way and why?
  3. what queryset I get in the get_search_results?
    I would love to hear any other tips on optimization as well
    Thank you!

See the Queryset optimization in Admin thread.