prefetch_related.py

>>> Product.objects.count()
220

# 220 queries - __str__ is called for each product
Product.objects.all()
[ "Jeans (cotton, skinny)", "Neon Shirt (attrx, attry)", ...]


# 2 queries - 1 query for products and 1 query for attributes.
# attributes are prefetched when products query is executed.
Product.objects.all().prefetch_related('attribues')
[ "Jeans (cotton, skinny)", "Neon Shirt (attrx, attry)", ...]