Install
Works with Drupal: 7.xUsing Composer to manage Drupal site dependencies
Downloads
Release notes
Halloween Stampede Release
If you have enabled stampede protection ($conf['memcache_stampede_protection'] = TRUE;), it is strongly recommended that you upgrade. If you are unable to upgrade, you should disable stampede protection.
What’s changed since 7.x-1.3-rc1
Nothing. No regressions were found in 7.x-1.3-rc1 so we're re-releasing this unchanged as 7.x-1.3.
What’s changed since 7.x-1.2
Overview
This release is primarily being made to fix a critical bug affecting the functionality of stampede protection in the memcache module. Affecting both 7.x-1.1 and 7.x-1.2, when stampede protection is enabled stale items will be returned even after a cache flush. Find more information at https://www.drupal.org/node/2099893#comment-9007685.
Details
- #2038405: Warn about potential security vulnerability - memcached exposed to outside world
suggest securing memcached service. - #2099893: Race condition in locking framework
Fixed [Stampede protection broken] Race condition in locking framework - #2270491: Integrity constraint violations when lots of writes happen
wrap veriable_set to catch race condition and prevent errors
Testing
7.x-1.3-rc1 was released on August 6th, 2014. NOTE: Drupal.org usage statistics only report a couple hundred websites testing this release candidate. ( https://www.drupal.org/project/usage/memcache )
We have done comprehensive load testing to ensure there have been no performance regressions. In fact, our tests show a consistent ~1% performance improvement when upgrading from 7.x-1.2 to 7.x-1.3 with the configuration recommended in the README. This improvement is due to fixing broken stampede protection logic.
The loadtests we used to generate the above numbers are now freely available at https://github.com/tag1consulting/drupal-loadtest. They assist in pre-populating a site with data, and then running a jMeter loadtest suite against the test website. While the tests aren’t comprehensive and only focus on common core functionality, they provide fantastic insight and detail into the performance differences between releases.
