python - Django 数据库路由

Question

我正在尝试使用两个数据库(1 个主数据库，1 个只读副本)运行我的 Django 应用程序。我的问题是，如果我在编写代码后立即尝试阅读，代码就会爆炸。例如:

• p = Product.objects.create()
• 1. Product.objects.get(id=p.id)

或

• 1. 如果用户被重定向到产品的详情页

代码运行速度比只读副本快得多。如果读取操作使用副本，代码就会崩溃，因为它没有及时更新。

有什么办法可以避免这种情况吗？例如，要读取的数据库是由请求而不是操作选择的？

我的路由器与 Django 的文档相同:

import random

class PrimaryReplicaRouter(object):
    def db_for_read(self, model, **hints):
        """
        Reads go to a randomly-chosen replica.
        """
        return random.choice(['replica1', 'replica2'])

    def db_for_write(self, model, **hints):
        """
        Writes always go to primary.
        """
        return 'primary'

    def allow_relation(self, obj1, obj2, **hints):
        """
        Relations between objects are allowed if both objects are
        in the primary/replica pool.
        """
        db_list = ('primary', 'replica1', 'replica2')
        if obj1._state.db in db_list and obj2._state.db in db_list:
            return True
        return None

    def allow_migrate(self, db, app_label, model_name=None, **hints):
        """
        All non-auth models end up in this pool.
        """
        return True

Answer 1

解决了:

class Model(models.Model): 
    objects = models.Manager()  -> objects only access master
    sobjects = ReplicasManager() -> sobjects access either master and replicas

    class Meta: 
        abstract = True  -> so django doesn't create a table

让每个模型都扩展这个而不是 models.Model，然后使用对象或对象，无论我只想访问 master 还是想访问 master 或 replicas