dormando edited this page Aug 13, 2016 · 2 revisions

Memcached 1.4.30 Release Notes

Date: 2016-8-11



Bugfix release, with a critical fix to large item support.


  • Add MemoryDenyWriteExecute to the systemd service
  • Handle end of line comment on memcached.conf
  • Add missing parameters and escape hypens as minus to manpage
  • Modernize unit file in systemd
  • crawler now uses rate limiter sleeps properly (CPU overusage)
  • add slab_chunk_max to stats settings


  • fix over-allocating with large item support.

If you set -I 2m, memcached was allocating 2 megabytes of memory per page, then only using 1mb. This would lead to it hitting the malloc limit with only 50% of the memory available before. This gets worse the more distant -I is from 1MB.

If you are still seeing issues with memory efficiency with large item support (-I set higher than 1m default), try the startup setting: -o slab_chunk_max=524288 Most workloads will function fine, and it should nearly always be better than how memory efficiency worked prior to the new feature (when using large items).

New Features


The following people contributed to this release since 1.4.29.

Note that this is based on who contributed changes, not how they were done. In many cases, a code snippet on the mailing list or a bug report ended up as a commit with your name on it.

Note that this is just a summary of how many changes each person made which doesn't necessarily reflect how significant each change was. For details on what led up into a branch, either grab the git repo and look at the output of git log 1.4.29..1.4.30 or use a web view.

     6  dormando
     2  Guillaume Delacour
     1  Craig Andrews
     1  Remi Collet