Django: Calculate the Sum of the column values through query

Question

I have a model

class ItemPrice( models.Model ):
     price = models.DecimalField ( max_digits = 8, decimal_places=2 )
     ....

I tried thi

Answer 1

Using cProfile profiler, I find that in my development environment, it is more efficient (faster) to sum the values of a list than to aggregate using Sum(). eg:

sum_a = sum([item.column for item in queryset]) # Definitely takes more memory.
sum_b = queryset.aggregate(Sum('column')).get('column__sum') # Takes about 20% more time.

I tested this in different contexts and it seems like using aggregate takes always longer to produce the same result. Although I suspect there might be advantages memory-wise to use it instead of summing a list.