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

[James Page]

** Description changed:

  [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]
- TBC
+ run attached memcache-test.py under python 2.
+ with proposed fixes, should be approximately 
  
  [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

** Attachment added: "memcache-test.py"
   https://bugs.launchpad.net/ubuntu/+source/python-memcache/+bug/1802487/+attachment/5215270/+files/memcache-test.py

** Description changed:

  [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 
+ 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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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:
  Triaged
Status in python-memcache source package in Cosmic:
  Triaged
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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