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

[Brian Murray]

Hello Ricardo, or anyone else affected,

Accepted python-memcache into cosmic-proposed. The package will build
now and be available at https://launchpad.net/ubuntu/+source/python-
memcache/1.57-2ubuntu0.18.10.1 in a few hours, and then in the -proposed
repository.

Please help us by testing this new package.  See
https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how
to enable and use -proposed.  Your feedback will aid us getting this
update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug,
mentioning the version of the package you tested and change the tag from
verification-needed-cosmic to verification-done-cosmic. If it does not
fix the bug for you, please add a comment stating that, and change the
tag to verification-failed-cosmic. In either case, without details of
your testing we will not be able to proceed.

Further information regarding the verification process can be found at
https://wiki.ubuntu.com/QATeam/PerformingSRUVerification .  Thank you in
advance for helping!

N.B. The updated package will be released to -updates after the bug(s)
fixed by this package have been verified and the package has been in
-proposed for a minimum of 7 days.

** Changed in: python-memcache (Ubuntu Cosmic)
       Status: In Progress => Fix Committed

** Tags added: verification-needed verification-needed-cosmic

** Changed in: python-memcache (Ubuntu Bionic)
       Status: In Progress => Fix Committed

** Tags added: verification-needed-bionic

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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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