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dormando edited this page Nov 21, 2020 · 1 revision

Memcached 1.6.9 Release Notes

Date: 2020-11-20

Download

http://www.memcached.org/files/memcached-1.6.9.tar.gz

Overview

This change has a few useful new features, along with a lot of bugfixes and some internal code reorganization for future projects. We have been questing to improve test quality and stamp down bugs that came in over the 1.6 series.

As usual many thanks to the numerous contributors who sent in patches or helped test this release!

Fixes

  • crawler: remove bad mutex unlock during error
  • idle_timeout: avoid long hangs during shutdown
  • extstore: use fcntl locking on disk file
  • portability fix for getsubopt
  • illumos build fixes + require libevent2
  • core: generalize extstore's defered IO queue
  • fix connection limit tests
  • logger: fix spurious watcher hangups
  • watcher.t: reduce flakiness
  • Extend test CA validity to 500 years
  • adjust "t/idle-timeout.t" be more forgiving

New Features

  • arm64: Re-add arm crc32c hw acceleration for extstore

  • restart mode: expose memory_file path in stats settings

  • 'shutdown graceful' command for raising SIGUSR1

  • Introduce NAPI ID based worker thread selection (see doc/napi_ids.txt)

  • item crawler hash table walk mode

The background item crawler thread is used by default to walk LRU's and actively reclaim expired items. It can also be used by end users to examine the cache via the lru_crawler metadump command.

The metadump command can be told to walk specific LRU's, in case you are curious what is taking up memory in lower or higher slab classes. On the downside LRU's will naturally reorder as things happen. There is also an issue where items that are very frequently accessed are invisible to the LRU crawler.

New with this release, if you invoke the crawler via: lru_crawler metadump hash, the crawler will instead visit each bucket in the hash table. This will ensure each item is visited once, but the search cannot be limited in the same way.

Note this does not in any way snapshot memory. If items are deleted or added to the hash table after the walk starts, they may or may not be seen.

Contributors

The following people contributed to this release since 1.6.8.

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 1.6.8..1.6.9 or use a web view.

    15	dormando
     2	Kevin Lin
     1	Ali Saidi
     1	Bernhard M. Wiedemann
     1	David Carlier
     1	Kleber
     1	Sridhar Samudrala
     1	Tianon Gravi
     1	pkarumanchi9
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