Opened 5 years ago

Closed 5 years ago

Last modified 5 years ago

#15324 closed (fixed)

memcached cache backend creating new connection for every action

Reported by: dlowe Owned by: nobody
Component: Core (Cache system) Version: 1.3-beta
Severity: Keywords: blocker regression
Cc: Triage Stage: Ready for checkin
Has patch: yes Needs documentation: no
Needs tests: no Patch needs improvement: no
Easy pickings: UI/UX:


r15005 introduced a problem for MemcachedCache caches: every call to any cache method which accesses the cache (add, get, set, delete, get_many, incr, decr, set_many, delete_many, clear and even close!) opens a brand-new connection to memcached via the self._lib.Client(...) call now hidden in self._cache. I think this is a major problem for busy sites who are aggressively caching: our site was brought down when we upgraded to 1.3_beta_1, as it very quickly exceeded the memcached concurrency limit.

I've attached a patch including a minimal test case.

I ran the tests against django trunk r15560, with python_memcached-1.44-py2.6.egg and python 2.6.5.

Attachments (1)

memcached_connection_reuse.patch (2.2 KB) - added by dlowe 5 years ago.

Download all attachments as: .zip

Change History (5)

Changed 5 years ago by dlowe

comment:1 Changed 5 years ago by russellm

  • Keywords blocker regression added
  • Needs documentation unset
  • Needs tests unset
  • Patch needs improvement unset
  • Triage Stage changed from Unreviewed to Ready for checkin

comment:2 Changed 5 years ago by russellm

There's a slight problem with the patch as presented -- I can't get the test case to fail (using python-memcached-1.45). I suspect this may have something to do with the internals of python-memcache, and its own internal connection reuse policies.

However, there is a clear behavioral difference between Django 1.2 and trunk with regards to connection creation, and fixing the problem is fairly trivial, so I'm willing to take this as an untested feature. If anyone manages to find a way to test this in a consistent way, I'm happy to apply the patch post-facto.

comment:3 Changed 5 years ago by russellm

  • Resolution set to fixed
  • Status changed from new to closed

In [15567]:

(The changeset message doesn't reference this ticket)

comment:4 Changed 5 years ago by jacob

  • milestone 1.3 deleted

Milestone 1.3 deleted

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