total_cost_benchmark.py

#!/usr/bin/env python

import os
import django
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'onlineshop.settings')
django.setup()
from django.db.models import Sum, F

import random, decimal
from placeorder.models import Order, OrderLine
from shop.models import Product

import timeit

p = Product.objects.first()
o = Order.objects.first()

def make_orderlines():
	ol_list = []
	for i in range(5000):
		ol = OrderLine(
			order        = o,
			product      = p,
			units        = random.randint(1, 100),
			pricePerUnit = decimal.Decimal(random.randint(100, 50000)) / 100,
		)
		#ol.save()
		ol_list.append(ol)

	OrderLine.objects.bulk_create(ol_list)

def func1():
	query = OrderLine.objects.all()
	query = query.annotate(product_cost=F('pricePerUnit') * F('units'))
	query = query.aggregate(Sum('product_cost'))
	return query['product_cost__sum']

	# select sum(pricePerUnit * units) as product_cost__sum from placeorder_orderline;


def func2():
	#return sum(map(lambda line: line.getProductCost(), OrderLine.objects.all()))
	return sum(item.getProductCost() for item in OrderLine.objects.all())


if __name__ == '__main__':
	import timeit
	print('Inserting orders ...')
	make_orderlines()
	print('{} orders inserted. Summing ...'.format(OrderLine.objects.count()))
	t1 = timeit.timeit("func1()", setup="from __main__ import func1", number=10)
	t2 = timeit.timeit("func2()", setup="from __main__ import func2", number=10)
	print('Method 1: {} seconds'.format(t1))
	print('Method 2: {} seconds'.format(t2))
	print('Method 2 is ~{} times slower than method 1'.format(int(t2/t1)))
	OrderLine.objects.all().delete()

	# len(OrderLine.objects.all()
	# OrderLine.objects.count()