More low-hanging query optimisations

registrasion/controllers/cart.py

@@ -8,6 +8,7 @@ from django.core.exceptions import ObjectDoesNotExist
 from django.core.exceptions import ValidationError
 from django.db import transaction
 from django.db.models import Max
+from django.db.models import Q
 from django.utils import timezone
 
 from registrasion.exceptions import CartValidationError
@@ -84,6 +85,8 @@ class CartController(object):
         revision is increased.
         '''
 
+        # TODO cache carts mid-batch?
+
         ctrl = cls.for_user(user)
         _id = ctrl.cart.id
 
@@ -180,22 +183,28 @@ class CartController(object):
         # Validate that the limits we're adding are OK
         self._test_limits(all_product_quantities)
 
+        new_items = []
+        products = []
         for product, quantity in product_quantities:
-            try:
-                product_item = commerce.ProductItem.objects.get(
-                    cart=self.cart,
-                    product=product,
-                )
-                product_item.quantity = quantity
-                product_item.save()
-            except ObjectDoesNotExist:
-                commerce.ProductItem.objects.create(
-                    cart=self.cart,
-                    product=product,
-                    quantity=quantity,
-                )
+            products.append(product)
 
-        items_in_cart.filter(quantity=0).delete()
+            if quantity == 0:
+                continue
+
+            item = commerce.ProductItem(
+                cart=self.cart,
+                product=product,
+                quantity=quantity,
+            )
+            new_items.append(item)
+
+        to_delete = (
+            Q(quantity=0) |
+            Q(product__in=products)
+        )
+
+        items_in_cart.filter(to_delete).delete()
+        commerce.ProductItem.objects.bulk_create(new_items)
 
     def _test_limits(self, product_quantities):
         ''' Tests that the quantity changes we intend to make do not violate

registrasion/controllers/conditions.py

@@ -154,12 +154,17 @@ class CategoryConditionController(IsMetByFilter, ConditionController):
         product from a category invoking that item's condition in one of their
         carts. '''
 
-        items = commerce.ProductItem.objects.filter(cart__user=user)
-        items = items.exclude(cart__status=commerce.Cart.STATUS_RELEASED)
-        items = items.select_related("product", "product__category")
-        categories = [item.product.category for item in items]
+        in_user_carts = Q(
+            enabling_category__product__productitem__cart__user=user
+        )
+        released = commerce.Cart.STATUS_RELEASED
+        in_released_carts = Q(
+            enabling_category__product__productitem__cart__status=released
+        )
+        queryset = queryset.filter(in_user_carts)
+        queryset = queryset.exclude(in_released_carts)
 
-        return queryset.filter(enabling_category__in=categories)
+        return queryset
 
 
 class ProductConditionController(IsMetByFilter, ConditionController):
@@ -171,12 +176,15 @@ class ProductConditionController(IsMetByFilter, ConditionController):
         ''' Returns all of the items from queryset where the user has a
         product invoking that item's condition in one of their carts. '''
 
-        items = commerce.ProductItem.objects.filter(cart__user=user)
-        items = items.exclude(cart__status=commerce.Cart.STATUS_RELEASED)
-        items = items.select_related("product", "product__category")
-        products = [item.product for item in items]
+        in_user_carts = Q(enabling_products__productitem__cart__user=user)
+        released = commerce.Cart.STATUS_RELEASED
+        in_released_carts = Q(
+            enabling_products__productitem__cart__status=released
+        )
+        queryset = queryset.filter(in_user_carts)
+        queryset = queryset.exclude(in_released_carts)
 
-        return queryset.filter(enabling_products__in=products)
+        return queryset
 
 
 class TimeOrStockLimitConditionController(
@@ -287,9 +295,4 @@ class VoucherConditionController(IsMetByFilter, ConditionController):
         ''' Returns all of the items from queryset where the user has entered
         a voucher that invokes that item's condition in one of their carts. '''
 
-        carts = commerce.Cart.objects.filter(
-            user=user,
-        )
-        vouchers = [cart.vouchers.all() for cart in carts]
-
-        return queryset.filter(voucher__in=itertools.chain(*vouchers))
+        return queryset.filter(voucher__cart__user=user)

registrasion/controllers/flag.py

@@ -4,6 +4,7 @@ import operator
 from collections import defaultdict
 from collections import namedtuple
 from django.db.models import Count
+from django.db.models import Q
 
 from .conditions import ConditionController
 
@@ -83,18 +84,16 @@ class FlagController(object):
 
             # Get all products covered by this condition, and the products
             # from the categories covered by this condition
-            cond_products = condition.products.all()
-            from_category = inventory.Product.objects.filter(
-                category__in=condition.categories.all(),
-            ).all()
-            all_products = cond_products | from_category
+
+            ids = [product.id for product in products]
+            all_products = inventory.Product.objects.filter(id__in=ids)
+            cond = (
+                Q(flagbase_set=condition) |
+                Q(category__in=condition.categories.all())
+            )
+
+            all_products = all_products.filter(cond)
             all_products = all_products.select_related("category")
-            # Remove the products that we aren't asking about
-            all_products = [
-                product
-                for product in all_products
-                if product in products
-            ]
 
             if quantities:
                 consumed = sum(quantities[i] for i in all_products)
@@ -221,6 +220,7 @@ _ConditionsCount = namedtuple(
 )
 
 
+# TODO: this should be cacheable.
 class FlagCounter(_FlagCounter):
 
     @classmethod

registrasion/views.py

@@ -445,14 +445,17 @@ def _handle_products(request, category, products, prefix):
 def _set_quantities_from_products_form(products_form, current_cart):
 
     quantities = list(products_form.product_quantities())
-
+    id_to_quantity = dict(i[:2] for i in quantities)
     pks = [i[0] for i in quantities]
     products = inventory.Product.objects.filter(
         id__in=pks,
     ).select_related("category")
 
+
+
+    # TODO: This is fundamentally dumb
     product_quantities = [
-        (products.get(pk=i[0]), i[1]) for i in quantities
+        (product, id_to_quantity[product.id]) for product in products
     ]
     field_names = dict(
         (i[0][0], i[1][2]) for i in zip(product_quantities, quantities)