id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
33297	ASGI: Dead persistent postgres connections are not closed sometimes	Matt Davis	nobody	"I have a two node cluster running a container with ASGI and Django backend for the ORM with uvicorn and fastapi--after 3 days one of the two nodes has resulted in a permanent Internal Server Error due to the DB connection being closed, the other node is still running fine.  I found a similar closed ticket (https://code.djangoproject.com/ticket/31905) but it was specifically about middleware, and this issue is not in the middleware.  I apologize if this issue ends up being one of the other libraries at play (DRF, uvicorn, fastapi), but I think that the actual cause of the stack trace is the closed Django DB connection which is contained in the top of the stack trace, `django/utils/asyncio.py"", line 26, in inner` is always calling for the same stale connection once the error condition happens, as in nothing ever refreshes it.

Django versions:
Django==3.2.8

{{{
django.db.utils.OperationalError: SSL SYSCALL error: EOF detected
INFO:     10.244.0.195:46240 - ""GET /blog/posts HTTP/1.1"" 500 Internal Server Error
ERROR:    Exception in ASGI application
Traceback (most recent call last):
  File ""/usr/local/lib/python3.10/site-packages/django/db/backends/base/base.py"", line 237, in _cursor
    return self._prepare_cursor(self.create_cursor(name))
  File ""/usr/local/lib/python3.10/site-packages/django/utils/asyncio.py"", line 26, in inner
    return func(*args, **kwargs)
  File ""/usr/local/lib/python3.10/site-packages/django/db/backends/postgresql/base.py"", line 236, in create_cursor
    cursor = self.connection.cursor()
psycopg2.InterfaceError: connection already closed
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
  File ""/usr/local/lib/python3.10/site-packages/uvicorn/protocols/http/httptools_impl.py"", line 375, in run_asgi
    result = await app(self.scope, self.receive, self.send)
  File ""/usr/local/lib/python3.10/site-packages/uvicorn/middleware/proxy_headers.py"", line 75, in __call__
    return await self.app(scope, receive, send)
  File ""/usr/local/lib/python3.10/site-packages/fastapi/applications.py"", line 208, in __call__
    await super().__call__(scope, receive, send)
  File ""/usr/local/lib/python3.10/site-packages/starlette/applications.py"", line 112, in __call__
    await self.middleware_stack(scope, receive, send)
  File ""/usr/local/lib/python3.10/site-packages/starlette/middleware/errors.py"", line 181, in __call__
    raise exc
  File ""/usr/local/lib/python3.10/site-packages/starlette/middleware/errors.py"", line 159, in __call__
    await self.app(scope, receive, _send)
  File ""/usr/local/lib/python3.10/site-packages/starlette/exceptions.py"", line 82, in __call__
    raise exc
  File ""/usr/local/lib/python3.10/site-packages/starlette/exceptions.py"", line 71, in __call__
    await self.app(scope, receive, sender)
  File ""/usr/local/lib/python3.10/site-packages/starlette/routing.py"", line 656, in __call__
    await route.handle(scope, receive, send)
  File ""/usr/local/lib/python3.10/site-packages/starlette/routing.py"", line 259, in handle
    await self.app(scope, receive, send)
  File ""/usr/local/lib/python3.10/site-packages/starlette/routing.py"", line 61, in app
    response = await func(request)
  File ""/usr/local/lib/python3.10/site-packages/fastapi/routing.py"", line 226, in app
    raw_response = await run_endpoint_function(
  File ""/usr/local/lib/python3.10/site-packages/fastapi/routing.py"", line 161, in run_endpoint_function
    return await run_in_threadpool(dependant.call, **values)
  File ""/usr/local/lib/python3.10/site-packages/starlette/concurrency.py"", line 39, in run_in_threadpool
    return await anyio.to_thread.run_sync(func, *args)
  File ""/usr/local/lib/python3.10/site-packages/anyio/to_thread.py"", line 28, in run_sync
    return await get_asynclib().run_sync_in_worker_thread(func, *args, cancellable=cancellable,
  File ""/usr/local/lib/python3.10/site-packages/anyio/_backends/_asyncio.py"", line 805, in run_sync_in_worker_thread
    return await future
  File ""/usr/local/lib/python3.10/site-packages/anyio/_backends/_asyncio.py"", line 743, in run
    result = func(*args)
  File ""/code/whitewhale/./fapi/blog.py"", line 47, in blog_posts
    return serializer.data
  File ""/usr/local/lib/python3.10/site-packages/rest_framework/serializers.py"", line 745, in data
    ret = super().data
  File ""/usr/local/lib/python3.10/site-packages/rest_framework/serializers.py"", line 246, in data
    self._data = self.to_representation(self.instance)
  File ""/usr/local/lib/python3.10/site-packages/rest_framework/serializers.py"", line 663, in to_representation
    return [
  File ""/usr/local/lib/python3.10/site-packages/django/db/models/query.py"", line 280, in __iter__
    self._fetch_all()
  File ""/usr/local/lib/python3.10/site-packages/django/db/models/query.py"", line 1324, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
  File ""/usr/local/lib/python3.10/site-packages/django/db/models/query.py"", line 51, in __iter__
    results = compiler.execute_sql(chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size)
  File ""/usr/local/lib/python3.10/site-packages/django/db/models/sql/compiler.py"", line 1173, in execute_sql
    cursor = self.connection.cursor()
  File ""/usr/local/lib/python3.10/site-packages/django/utils/asyncio.py"", line 26, in inner
    return func(*args, **kwargs)
  File ""/usr/local/lib/python3.10/site-packages/django/db/backends/base/base.py"", line 259, in cursor
    return self._cursor()
  File ""/usr/local/lib/python3.10/site-packages/django/db/backends/base/base.py"", line 236, in _cursor
    with self.wrap_database_errors:
  File ""/usr/local/lib/python3.10/site-packages/django/db/utils.py"", line 90, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File ""/usr/local/lib/python3.10/site-packages/django/db/backends/base/base.py"", line 237, in _cursor
    return self._prepare_cursor(self.create_cursor(name))
  File ""/usr/local/lib/python3.10/site-packages/django/utils/asyncio.py"", line 26, in inner
    return func(*args, **kwargs)
  File ""/usr/local/lib/python3.10/site-packages/django/db/backends/postgresql/base.py"", line 236, in create_cursor
    cursor = self.connection.cursor()
django.db.utils.InterfaceError: connection already closed
}}}

Only a restart of the application fixes the problem."	Bug	closed	Uncategorized	3.2	Normal	duplicate			Unreviewed	0	0	0	0	0	0