django mysql thread-safety analyse

djang_db_thread_safety_analyse.md

• source： https://stackoverflow.com/questions/34695052/how-is-django-persistent-database-connections-thread-safe

The ConnectionHandler is not a connection -- it only handles connections. It does so in a perfectly thread-safe manner by storing them on self._connections, which is a thread.local instance. The ConnectionHandler overrides getitem to support thread-local connections. When you access connections['default'], it looks if the default attribute exists on self._connections, which is a thread local. If it does, that would be the connection to the default database for the current thread. If it doesn't, it'll create a new one and set it on self._connections. Other threads won't be able to access this connection, since it's set on a thread local object. In the end it pretty much comes down to the public API. Setting a ConnectionHandler on a thread-local object would work as well, but the public API would be more complicated than it currently is, since user code would manually need to check if the handler for the current thread exists.