Question

我的django应用程序使用django-rest-framework和MySQL。我测试了我的应用程序，但几乎功能的响应时间很长。我不知道是什么问题。

这是响应时间最长的功能之一。

   180232 function calls (171585 primitive calls) in 1.110 seconds

   Ordered by: internal time
   List reduced from 757 to 151 due to restriction <0.2>

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
      105    0.597    0.006    0.597    0.006 /Users/jyj/.pyenv/versions/logispot_app_env/lib/python3.6/site-packages/MySQLdb/connections.py:268(query)
        2    0.154    0.077    0.174    0.087 /Users/jyj/.pyenv/versions/logispot_app_env/lib/python3.6/site-packages/MySQLdb/connections.py:81(__init__)
        4    0.020    0.005    0.020    0.005 /Users/jyj/.pyenv/versions/logispot_app_env/lib/python3.6/site-packages/MySQLdb/connections.py:254(autocommit)
8800/3582    0.010    0.000    0.828    0.000 {built-in method builtins.getattr}
    20156    0.010    0.000    0.022    0.000 {built-in method builtins.isinstance}
  200/100    0.009    0.000    0.886    0.009 /Users/jyj/.pyenv/versions/logispot_app_env/lib/python3.6/site-packages/rest_framework/serializers.py:479(to_representation)
        2    0.009    0.005    0.009    0.005 {function Connection.set_character_set at 0x109b506a8}
     6920    0.009    0.000    0.009    0.000 {built-in method builtins.hasattr}
                                      ....

此功能是列表的第一页，总计数为1000，页面大小为100.每个记录只加入一个表。查询花了很长时间，所以我将Django ORM更改为Raw Query但时间相同。（也许我使用了错误的原始查询）

甚至验证检查响应时间长

        2199 function calls (2133 primitive calls) in 0.195 seconds

   Ordered by: internal time
   List reduced from 419 to 84 due to restriction <0.2>

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
        2    0.153    0.076    0.169    0.084 /Users/jyj/.pyenv/versions/logispot_app_env/lib/python3.6/site-packages/MySQLdb/connections.py:81(__init__)
        4    0.016    0.004    0.016    0.004 /Users/jyj/.pyenv/versions/logispot_app_env/lib/python3.6/site-packages/MySQLdb/connections.py:254(autocommit)
        3    0.014    0.005    0.014    0.005 /Users/jyj/.pyenv/versions/logispot_app_env/lib/python3.6/site-packages/MySQLdb/connections.py:268(query)
        2    0.008    0.004    0.008    0.004 {function Connection.set_character_set at 0x109b506a8}

我认为它必须不到60毫秒。（也许我的想法是错的）

django查询太慢或我的应用程序出了什么问题？我知道这是什么问题。

DEBUG在False

settings

它只是本地runserver未部署。但部署时的响应时间几乎相同（部署速度更快，但查询时间相同）
抱歉信息不佳。我的网络开发经验只有半年时间。如果你想要更多，我会尝试。

修改查看代码

class OrderListCreationAPI(generics.ListCreateAPIView):
    permission_classes = (
        permissions.IsAuthenticatedOrReadOnly,
        IsAdminOrClient,
    )
    pagination_class = StandardListPagination


    def get_queryset(self):
        if self.request.method == 'GET':
            queryset = CacheOrderList.objects.all()
            return queryset
        else:
            return Order.objects.all()

    def get_serializer_class(self):
        if self.request.method == 'GET':
            return CacheOrderListSerializer
        else:
            return OrderSerializer

串行器代码

class CacheOrderListSerializer(serializers.ModelSerializer):
    base = CacheBaseSerializer(read_only=True)

    class Meta:
        model = CacheOrderList
        fields = '__all__'

型号代码

class CacheBase(models.Model):
    created_time = models.DateTimeField(auto_now_add=True)
    order = models.OneToOneField('order.Order', on_delete=models.CASCADE, related_name='cache', primary_key=True)
    driver_user = models.ForeignKey('member.DriverUser', on_delete=models.SET_NULL, null=True)
    client_name = models.CharField(max_length=20, null=True)
    load_address = models.CharField(max_length=45, null=True)
    load_company = models.CharField(max_length=20, null=True)
    load_date = models.DateField(null=True)
    load_time = models.CharField(max_length=30)
    unload_address = models.CharField(max_length=45, null=True)
    unload_company = models.CharField(max_length=20, null=True)
    unload_date = models.DateField(null=True)
    unload_time = models.CharField(max_length=30)
    stop_count = models.IntegerField(default=0)
    is_round = models.BooleanField(default=False)
    is_mix = models.BooleanField(default=False)
    car_ton = models.CharField(max_length=15, null=True)
    weight = models.FloatField(null=True)
    payment_method = models.BooleanField(default=s.ORDER_PAYMENT_METHOD_ADVANCE)
    contract_fee = models.IntegerField(null=True)
    driver_fee = models.IntegerField(null=True)
    order_fee = models.IntegerField(null=True)
    is_deleted = models.BooleanField(default=False)


class CacheOrderList(models.Model):
    base = models.OneToOneField(CacheBase, on_delete=models.CASCADE, related_name='order_list')
    order_status = models.IntegerField(null=True)
    order_created_time = models.DateTimeField(null=True)
    car_type = models.CharField(max_length=10, null=True)
    asignee = models.CharField(max_length=20, null=True)
    objects = CacheManager()

    class Meta:
        ordering = ('-order_created_time',)
        db_table = 'CacheOrderList'

EDIT2 在列表功能中，应用程序已经获得了100个项目，但之后，应用程序再次查询每个1项。不使用已经获得的项目。因此，每个查询花费的时间为100 *。

这可能是因为序列化程序没有使用分页所获得的记录。所以分页2查询+序列化器100查询+其他。

我不知道为什么会这样。

Answer 1

在CacheOrderList查询集中使用select_related作为基本字段。这将准备一个查询集缓存，其中包含您在方法中提供的外键关联，这基本上不会一次又一次地击中数据库。

示例：

button, button.new { color: dimgray; } button > *, button.new > * { display: inline-block; vertical-align: middle; } button.new { color: green; } button.new:hover, button.new.new:hover { color: darkgreen; }

python django响应时间长但不知道出了什么问题

1 个答案: