Commit 96658ef2 authored by Russell Keith-Magee's avatar Russell Keith-Magee
Browse files

Fixed #12057 -- Corrected regression of caching performance when a model... 

Fixed #12057 -- Corrected regression of caching performance when a model contained a callable default. Thanks to Michael Thornhill for the excellent assistance tracking this problem.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@11681 bcc190cf-cafb-0310-a4f2-bffc1f526a37
parent c5c7791e

AUTHORS

+1 −1
Original line number Diff line number Diff line
@@ -422,7 +422,7 @@ answer newbie questions, and generally made Django that much better: 
    Travis Terry <tdterry7@gmail.com>

    thebjorn <bp@datakortet.no>

    Zach Thompson <zthompson47@gmail.com>

    Michael Thornhill

    Michael Thornhill <michael.thornhill@gmail.com>

    Deepak Thukral <deep.thukral@gmail.com>

    tibimicu@gmx.net

    tobias@neuyork.de

django/db/models/base.py

+10 −2
Original line number Diff line number Diff line
@@ -293,7 +293,14 @@ class Model(object): 
                        if rel_obj is None and field.null:

                            val = None

                else:

                    val = kwargs.pop(field.attname, field.get_default())

                    try:

                        val = kwargs.pop(field.attname)

                    except KeyError:

                        # This is done with an exception rather than the

                        # default argument on pop because we don't want

                        # get_default() to be evaluated, and then not used.

                        # Refs #12057.

                        val = field.get_default()

            else:

                val = field.get_default()

            if is_related_object:
@@ -346,7 +353,7 @@ class Model(object): 
        """

        data = self.__dict__

        if not self._deferred:

            return (self.__class__, (), data)

            return super(Model, self).__reduce__()

        defers = []

        pk_val = None

        for field in self._meta.fields:
@@ -359,6 +366,7 @@ class Model(object): 
                    # once.

                    obj = self.__class__.__dict__[field.attname]

                    model = obj.model_ref()



        return (model_unpickle, (model, defers), data)



    def _get_pk_val(self, meta=None):

tests/regressiontests/cache/models.py

+11 −0
Original line number Diff line number Diff line 
from django.db import models

from datetime import datetime



def expensive_calculation():

    expensive_calculation.num_runs += 1

    return datetime.now()



class Poll(models.Model):

    question = models.CharField(max_length=200)

    answer = models.CharField(max_length=200)

    pub_date = models.DateTimeField('date published', default=expensive_calculation)

tests/regressiontests/cache/tests.py

+42 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ from django.core.cache.backends.base import InvalidCacheBackendError 
from django.http import HttpResponse, HttpRequest

from django.utils.cache import patch_vary_headers, get_cache_key, learn_cache_key

from django.utils.hashcompat import md5_constructor

from regressiontests.cache.models import Poll, expensive_calculation



# functions/classes for complex data type tests

def f():
@@ -211,6 +212,47 @@ class BaseCacheTests(object): 
        self.cache.set("stuff", stuff)

        self.assertEqual(self.cache.get("stuff"), stuff)



    def test_cache_read_for_model_instance(self):

        # Don't want fields with callable as default to be called on cache read

        expensive_calculation.num_runs = 0

        Poll.objects.all().delete()

        my_poll = Poll.objects.create(question="Well?")

        self.assertEqual(Poll.objects.count(), 1)

        pub_date = my_poll.pub_date

        self.cache.set('question', my_poll)

        cached_poll = self.cache.get('question')

        self.assertEqual(cached_poll.pub_date, pub_date)

        # We only want the default expensive calculation run once

        self.assertEqual(expensive_calculation.num_runs, 1)



    def test_cache_write_for_model_instance_with_deferred(self):

        # Don't want fields with callable as default to be called on cache write

        expensive_calculation.num_runs = 0

        Poll.objects.all().delete()

        my_poll = Poll.objects.create(question="What?")

        self.assertEqual(expensive_calculation.num_runs, 1)

        defer_qs = Poll.objects.all().defer('question')

        self.assertEqual(defer_qs.count(), 1)

        self.assertEqual(expensive_calculation.num_runs, 1)

        self.cache.set('deferred_queryset', defer_qs)

        # cache set should not re-evaluate default functions

        self.assertEqual(expensive_calculation.num_runs, 1)



    def test_cache_read_for_model_instance_with_deferred(self):

        # Don't want fields with callable as default to be called on cache read

        expensive_calculation.num_runs = 0

        Poll.objects.all().delete()

        my_poll = Poll.objects.create(question="What?")

        self.assertEqual(expensive_calculation.num_runs, 1)

        defer_qs = Poll.objects.all().defer('question')

        self.assertEqual(defer_qs.count(), 1)

        self.cache.set('deferred_queryset', defer_qs)

        self.assertEqual(expensive_calculation.num_runs, 1)

        runs_before_cache_read = expensive_calculation.num_runs

        cached_polls = self.cache.get('deferred_queryset')

        # We only want the default expensive calculation run on creation and set

        self.assertEqual(expensive_calculation.num_runs, runs_before_cache_read)



    def test_expiration(self):

        # Cache values can be set to expire

        self.cache.set('expire1', 'very quickly', 1)