[Bug 1802487] Re: Fix performance regression in v1.57
Launchpad Bug Tracker
1802487 at bugs.launchpad.net
Tue Dec 4 20:20:10 UTC 2018
This bug was fixed in the package python-memcache -
1.57-2ubuntu0.18.10.1
---------------
python-memcache (1.57-2ubuntu0.18.10.1) cosmic; urgency=medium
* d/p/py2-perf.patch: Cherry pick fix to use native C implementation
for pickle under Python 2, resolving issues with performance
degradation (LP: #1802487).
-- James Page <james.page at ubuntu.com> Thu, 22 Nov 2018 11:50:53 +0000
** Changed in: python-memcache (Ubuntu Cosmic)
Status: Fix Committed => Fix Released
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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 Released
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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