[Bug 1802487] Re: Fix performance regression in v1.57

[James Page]

bionic:

release pocket version

# time python memcache-test.py

real	0m21.069s
user	0m14.304s
sys	0m3.174s

-proposed version:

# time python memcache-test.py

real	0m13.247s
user	0m8.359s
sys	0m2.727s


cosmic:

release pocket:

# time python memcache-test.py

real	0m19.094s
user	0m13.056s
sys	0m3.161s

-proposed version

# time python memcache-test.py

real	0m13.996s
user	0m8.968s
sys	0m2.760s



** Tags removed: verification-needed verification-needed-bionic verification-needed-cosmic
** Tags added: verification-done verification-done-bionic verification-done-cosmic

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https://bugs.launchpad.net/bugs/1802487

Title:
  Fix performance regression in v1.57

Status in python-memcache package in Ubuntu:
  Fix Released
Status in python-memcache source package in Bionic:
  Fix Committed
Status in python-memcache source package in Cosmic:
  Fix Committed
Status in python-memcache source package in Disco:
  Fix Released

Bug description:
  [Impact]
  Performance under Python 2 with this package since 1.54 is poor due to the lack of use of the native C implementation of pickle.

  [Test Case]
  run attached memcache-test.py under python 2.
  with proposed fixes, should be approximately 2/3 of the execution time of the unpatched version.

  [Regression Potential]
  The picked fix is relatively minor and simply adjusts the import under Py2 to use the native C implementation so regression potential will be low.

  [Original Bug Report]
  Just migrated a python 2 application from 14.04 LTS to 18.04 LTS and got a serious performance degradation. Like 1000 times slower. After some profiling it was concluded that the problem was the transition from cPickle back to pickle for data serialization.

  This is a problem fixed in version 1.58.
  https://github.com/linsomniac/python-memcached/releases/tag/1.58

  Please upgrade python-memcache to a more recent version or patch the
  current version.

  Versions affected: Ubuntu 16.04 LTS and Ubuntu 18.04 LTS

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