Question

我有一个遗留应用程序（目前）使用Django来有效地显示数据。我的一个工作测试的样本看起来像这样。

def test_add_property_value(self):
    """Test set / get a value"""
    # This will do some external process which occcurs to the db.
    pm = Pm(mysql_db='test_bugs')
    tree =  pm.add_release_tree()
    prop_type, pmvalue = ("string", "Funny Business")
    pmproperty = "%s_%s_basic" % (tree[0].name, prop_type)
    pm.add_property_definition(pmproperty, prop_type=prop_type)
    pm.add_propval(pmproperty, value=pmvalue, project=tree[0].name)

    # Now use Django to pull the value back out..
    project = Project.objects.get(name=tree[0].name)
    property = project.get_property(pmproperty) # Custom query using sql.raw
    self.assertEqual(pmvalue, property.value)

您可以看到它是基本的A / B测试。现在我发现了一个限制，我似乎无法解决多个外部添加 - 检查 - 循环查询失败。修改上述代码失败，因为出现查询无法甚至运行。

def test_add_property_value(self):
    """Test set / get a value"""

    # This will do some external process which occcurs to the db.
    pm = Pm(mysql_db='test_bugs', p4_port = settings.ICMSERVER_TEST_PORT)
    tree = pm.add_release_tree()
    prop_type, pmvalue = ("string", "Funny Business")
    pmproperty = "%s_%s_basic" % (tree[1].name, prop_type)
    pm.add_property_definition(pmproperty, prop_type=prop_type)
    pm.add_propval(pmproperty, value=pmvalue, project=tree[1].name)

    # Now use Django to pull the value back out..
    project = Project.objects.get(name=tree[1].name)
    property = project.get_property(pmproperty)
    self.assertEqual(pmvalue, property.value)

    # ONLY CHANGE WAS TO ADD THIS..

    # This will do some external process which occcurs to the db.
    pmproperty = "%s_%s_basic_two" % (tree[1].name, prop_type)
    pm.add_property_definition(pmproperty, prop_type=prop_type)
    pm.add_propval(pmproperty, value=pmvalue, project=tree[1].name)

    # Now use Django to pull the value back out..
    project = Project.objects.get(name=tree[1].name)
    property = project.get_property(pmproperty)
    self.assertEqual(pmvalue, property.value)

我已经阅读了CACHE_BACKEND，但似乎没有帮助。还有其他想法吗？经过进一步调查后，这似乎与我的外部数据库无关。 Arghh ..感觉就像星期一！

这是一个缓存问题BTW - 设置CACHE_BACKEND ='dummy：///'或'locmem：///'什么也没做。
如何更好地诊断此问题？

由于

更新

以下是最终答案 - 2个小调整......基于Daniel和Severio。很赞赏指针！

class PropertyTests(TransactionTestCase):  #CHANGE1
    def test_add_property_value(self):
        """Test set / get a value"""

        import logging
        l = logging.getLogger('django.db.backends')
        l.setLevel(logging.DEBUG)
        l.addHandler(logging.StreamHandler())

        # This will do some external process which occcurs to the db.
        pm = Pm(mysql_db='test_bugs', p4_port = settings.ICMSERVER_TEST_PORT)
        tree = pm.add_release_tree()
        prop_type, pmvalue = ("string", "Funny Business")
        pmproperty = "%s_%s_basic" % (tree[1].name, prop_type)
        pm.add_property_definition(pmproperty, prop_type=prop_type)
        pm.add_propval(pmproperty, value=pmvalue, project=tree[1].name)

        # Now use Django to pull the value back out..
        project = Project.objects.get(name=tree[1].name)
        property = project.get_property(pmproperty)
        self.assertEqual(pmvalue, property.value)

        # This will do some external process which occcurs to the db.
        pmproperty = "%s_%s_basic_two" % (tree[1].name, prop_type)
        pm.add_property_definition(pmproperty, prop_type=prop_type)
        pm.add_propval(pmproperty, value=pmvalue, project=tree[1].name)

        # Now use Django to pull the value back out..
        Project.objects.update() #CHANGE2
        project = Project.objects.get(name=tree[1].name)
        property = project.get_property(pmproperty)
        self.assertEqual(pmvalue, property.value)

Answer 1

这可能不是交易问题。管理员（Project.objects）需要被告知数据更改，因为它的设计可以在短时间内生效。

您正在查询同一个查询Project.objects.get(name=tree[1].name)两次，并且管理员不再执行它，因为它认为它已经有正确的数据。

在第二次查询之前，执行

Project.objects.update()

使管理器缓存无效。失效后的结果应该是最新的。

Django测试 - 外部修改数据时的多个查询。缓存问题？

1 个答案: