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dormando edited this page Mar 8, 2023 · 1 revision

Memcached 1.6.19 Release Notes

Date: 2023-3-8

Download

http://www.memcached.org/files/memcached-1.6.19.tar.gz

Overview

Many fixes and new features for the Proxy feature. Rest are small fixes or code cleanups to the cache daemon. If you're trying out the Proxy code, please upgrade or continue to track the next branch.

If you use the lru_crawler metadump hash command, specifically the hash mode, there is a fix for potential slowdowns.

-Werror is no longer the default when compiling. Add --enable-werror to restore the feature.

Fixes

  • replace 2&>1 by 2>&1 in rpm spec file
  • log: fix race condition while incrementing log entries dropped
  • Add new pkg-config dependencies to dockerfiles
  • Document missing flags of Meta Arithmetic
  • configure.ac: add --enable-werror
  • proxy: reduce noise for dead backends
  • proxy: more await unit tests
  • proxy: fix trailingdata error with ascii multiget misses
  • crawler: don't hold lock while writing to network
  • proxy: redo libevent handling code (speedup/fixes)
  • proxy: fix "missingend" error on reading responses
  • proxy: add read buffer data to backend error messages
  • proxy: fix partial responses on backend timeouts
  • proxy: disallow overriding mn command
  • tests: timedrun SIGHUP pass-thru
  • proxy: new integration tests.
  • proxy: fix mismatched responses after bad write
  • proxy: fix stats deadlock caused by await code
  • proxy: clean logic around lua yielding
  • core: remove *c from some response code
  • core: simplify background IO API
  • core: remove *conn object from cache commands

New Features

  • crawler: add lru_crawler mgdump command

For more efficiently getting the keylist back out of the server. A utility demonstrating its usage can be found here: https://github.com/memcached/mcdumpload

  • proxy: allow workers to run IO optionally

If iothread = false is added as an option to mcp.pool(), each worker thread will handle its own backend IO for this pool. Instead of one tcp connection there will be one per worker thread. This allows mixing and matching (ie; use worker threads for high data rate backends, use IO thread for background IO's)

  • proxy: add mcp.backend(t) for more overrides

See tests, examples, documentation. Allows overriding timeouts, number of retries, and so on, on a per-backend basis.

  • proxy: add mcp.await_logerrors()

New form of mcp.await() which emits a log line for every response that ends in an error, after the main request has returned

  • proxy: add mcp.internal(r) API

An experimental API for accessing the cache server embedded in every proxy. Executes the command and retrieves a response object as though the command were executed against a remote backend. This allows creating pools of proxies which can answer responses directly, while doing replication to remote zones and other tasks.

Contributors

The following people contributed to this release since 1.6.18.

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 1.6.18..1.6.19 or use a web view.

    28	dormando
     5	xuesenliang
     1	David Carlier
     1	Fabrice Fontaine
     1	Mate Borcsok
     1	Olof Nord
     1	Patrice Duroux
     1	Ramasai
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