# Cache connection leak

**URL:** <https://forum.djangoproject.com/t/cache-connection-leak/35099>\
**Category:** Async/Channels\
**Created:** [September 25, 2024, 1:39pm UTC](https://forum.djangoproject.com/t/cache-connection-leak/35099 "2024-09-25T13:39:58Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![daviderie](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/daviderie/32/24145_2.png) [@daviderie](https://forum.djangoproject.com/u/daviderie)\
**Post date:** [September 25, 2024, 1:39pm UTC](https://forum.djangoproject.com/t/cache-connection-leak/35099/1 "2024-09-25T13:39:58Z")

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The Django documentation states that “You can access the caches configured in the CACHES setting through a dict-like object: django.core.cache.caches. Repeated requests for the same alias in the same thread will return the same object.” However, I have a system that shows this statement is false. I am using Django 4.2 and the PyMemcache backend. When I access the cache from an asyncio Task using sync\_to\_async, a new PyMemcacheCache instance is created each time I run a new Task to access it. This problem is documented in [#33625 (Under ASGI, PyLibMCCache closes memcached connection after every request) – Django](https://code.djangoproject.com/ticket/33625).

But my problem is worse because the new cache connection created in every Task is not always closed. I cannot tell why it is sometimes closed and sometimes not, but a factor is spawning other asyncio Tasks from the Task accessing the cache. I can avoid the problem by removing one of the Tasks that I spawn immediately after accessing the cache, but I don’t understand why this influences it. I believe it has to do with the Context and ContextVar used to store the PyMemcacheCache instance. If I force the cache backend to use a threading.Local instead, then the backend keeps one connection open as the documentation states, and I no longer have a connection leak.

If the author of the above ticket is correct, a ContextVar is not necessary and is in fact causing unwanted behavior like opening a new connection to the cache every time and not always closing that connection, causing a leak.

Is anyone else experiencing this? Is there something I can do to safely access the cache from an async thread?

Thanks.

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<div class="post-metadata">

**Author:** ![daviderie](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/daviderie/32/24145_2.png) [@daviderie](https://forum.djangoproject.com/u/daviderie)\
**Post date:** [September 26, 2024, 4:11pm UTC](https://forum.djangoproject.com/t/cache-connection-leak/35099/2 "2024-09-26T16:11:54Z")

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I can work around this problem by running the part of the code that accesses the cache in its own Task. I don’t understand why that fixes the issue, though.