00-RELEASENOTES

Redis 5.0 release notes
=======================

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Upgrade urgency levels:

LOW:      No need to upgrade unless there are new features you want to use.
MODERATE: Program an upgrade of the server, but it's not urgent.
HIGH:     There is a critical bug that may affect a subset of users. Upgrade!
CRITICAL: There is a critical bug affecting MOST USERS. Upgrade ASAP.
SECURITY: There are security fixes in the release.
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Redis 5.0 RC1   Released Tue May 29 14:14:11 CEST 2018
================================================================================

Upgrade urgency LOW: This is the first RC of Redis 5.

Introduction to the Redis 5 release
===================================

Redis 5 is a release focused on a few important features. While Redis 4
was very very focused on operations, Redis 5 changes are mostly user-facing,
with the implementation of new data types and operations on top of existing
types. The following are the major features of this release:

1. The new Stream data type. https://redis.io/topics/streams-intro
2. New Redis modules APIs: Timers and Cluster API.
3. RDB now store LFU and LRU information.
4. The cluster manager was ported from Ruby (redis-trib.rb) to C code
   inside redis-cli. Check `redis-cli --cluster help` for more info.
5. New sorted set commands: ZPOPMIN/MAX and blocking variants.
6. Active defragmentation version 2.
7. Improvemenets in HyperLogLog implementations.
8. Better memory reporting capabilities.
9. Many commands with sub-commands now have an HELP subcommand.
10. Better performances when clients connect and disconnect often.
11. Many bug fixes and other random improvements.
12. Jemalloc was upgraded to version 5.1

Thanks to all the users and developers who made this release possible.
We'll follow up with more RC releases, until the code looks production ready
and we don't get reports of serious issues for a while.

A special thank you for the amount of work put into this release
(in decreasing number of commits) by:

Fabio Nicotra, <artix2@gmail.com>
Soloestoy <zhaozhao.zz@alibaba-inc.com>
Itamar Haber <itamar@redislabs.com>
Oran Agra <oran@redislabs.com>
Dvir Volk <dvirsky@gmail.com>
dejun.xdj <dejun.xdj@alibaba-inc.com>
Guy Benoish <guy.benoish@redislabs.com>
Charsyam <charsyam@gmail.com>
Otmar Ertl <otmar.ertl@gmail.com>
Jan-Erik Rediger <janerik@fnordig.de>
Spinlock <wnzheng@gmail.com>

Migrating from 4.0 to 5.0
=========================

Redis 4.0 is mostly a strict subset of 5.0, you should not have any problem
upgrading your application from 4.0 to 5.0. However this is a list of small
non-backward compatible changes introduced in the 5.0 release:

* redis-cli now implements the cluster management tool. We still ship the
  old redis-trib, but new fixes will be implemented only in redis-cli.
  See `redis-cli --cluster help` for more info.

* The RDB format changed. Redis 5.0 is still able to read 4.0 (and all the
  past versions) files, but not the other way around.

* Certain log formats and sentences are different in Redis 5.0.

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Credits: For each release, a list of changes with the relative author is
provided. Where not specified the implementation and design is done by
Salvatore Sanfilippo. Thanks to Redis Labs for making all this possible.
Also many thanks to all the other contributors and the amazing community
we have.

Commit messages may contain additional credits.

Enjoy,
Salvatore