dormando edited this page Aug 24, 2016 · 2 revisions

Memcached 1.4.31 Release Notes

Date: 2016-8-19



Big new feature: lru_crawler metadump all, will now dump (most of) the metadata for (all of) the items in the cache. As opposed to cachedump, it does not cause severe performance problems and has no limits on the amount of keys that can be dumped.


  • More fixes for defaults related to large item support.
  • Several improvements to how the LRU crawler's default background job is launched. Should be less aggressive.
  • Fix LRU crawler rate limiting sleep never actually being used.

New Features

If -o modern is in use (or at least -o lru_crawler), a new command is usable: lru_crawler metadump [all|1|2|3]. You may dump all of the metadata for a particular slab class, a list of slab classes, or all slab classes.

This is useful for inspection, pulling cache data from one server to another, etc.

This is not a way to replicate a cache: it is an inconsistent non-multiversioned grab of the key storage. It makes a best effort to not include duplicates but a small number can happen on busy servers.

Many thanks for Netflix, for sponsoring and patiently testing the work done in this release!

More details and code can be seen in the PR:


The following people contributed to this release since 1.4.30.

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 1.4.30..1.4.31 or use a web view.

    14  dormando