00-RELEASENOTES

Redis 3.2 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.
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--[ Redis 3.2.0 RC3 (version 3.1.103) ] Release date: 28 jan 2016

Upgrade urgency MODERATE: this release fixes a non trivial Sentinel crash.

* [FIX] avg_ttl reporting in INFO improved. (Salvatore Sanfilippo)
* [FIX] Sentinel: improve handling of known Sentinel instances.
        (Salvatore Sanfilippo, thanks to Paweł Kowalczykf or the original
         crash report).
* [FIX] Redis Cluster address update (via gossip section) processing improved
        to avoid initiating inwanted handshakes.

--[ Redis 3.2.0 RC2 (version 3.1.102) ] Release date: 25 jan 2016

Upgrade urgency MODERATE: this release fixes important Redis Cluster bugs.

* [FIX] Many fixes to MIGRATE multiple keys implementation. The command
        could handle errors in a faulty way leading to crashes or other
        unexpected behaviors. MIGRATE command refactoring.
        (The analysis of the faulty conditions was conducted by
         Kevin McGehee. The fix was developed by Salvatore Sanfilippo)
* [FIX] A Redis Cluster node crash was fixed because of wrong handling of
        node->slaveof pointers.
        (Reported by JackyWoo, fixed by Salvatore Sanfilippo)
* [FIX] Fix redis-trib rebalance when nodes need to be left empty because
        the specified weight is zero.
        (Reported by Shahar Mor, fixed by Salvatore Sanfilippo)
* [FIX] MIGRATE: Never send -ASK redirections for MIGRATE when there are
        open slots. Redis-trib and other cluster management utility must
        always be free to move keys between nodes about open slots, in order
        to reshard, fix the cluster configuration, and so forth.
        (Salvatore Sanfilippo)
* [FIX] Lua debugger crash when printing too deeply nested objects.
        (Reported by Paul Kulchenko, fixed by Salvatore Sanfilippo)
* [FIX] Redis-cli implementation of Lua debugging now allows to use the
        SCRIPT DEBUG command directly, switching to debugging mode as needed.
        (Reported by Paul Kulchenko, fixed by Salvatore Sanfilippo)
* [FIX] Redis-trib is now able to fix more errors. A new CLUSTER subcommand
        called BUMPEPOCH was introduced in order to support new modes
        for the "fix" subcommand. (Salvatore Sanfilippo)
* [NEW] Redis proctected mode: this feature improves Redis security and makes
        harder to run Redis in a configuration that is unsecure because no
        firewalling was used in order to protect Redis from external accesses.
        See this Reddit post for more info: https://www.reddit.com/r/redis/comments/3zv85m/new_security_feature_redis_protected_mode/ (Salvatore Sanfilippo)
* [NEW] Cluster/Sentinel tests now use OSX leak to perform leak detection
        at the end of every unit. (Salvatore Sanfilippo)
* [NEW] Detect and show server crashes during Cluster/Sentinel tests.
        (Salvatore Sanfilippo)
* [NEW] More reliable Cluster/Sentinel test becuase of timing errors and
        -LOADING errors. (Salvatore Sanfilippo)

--[ Redis 3.2.0 RC1 (version 3.1.101) ] Release date: 23 dec 2015

This is the first release candidate of Redis 3.2. The changelog above shows
what's new in this release. In the next of the following weeks we'll test
in depth every feature and we'll release new RCs as bugs are discovered
and fixed. Note that while 3.2 looks solid already, it contains many changes
to its internals. It's still fresh code compared to 3.0.

General changes:

* [NEW] Lua scripts "effect replication". Makes possible to write scripts
        with side effects, use of random commands, and so forth.
        (Salvatore Sanfilippo)
* [NEW] Lua scripts selective replication. Makes possible to replicate to
        slaves and AOF only selected parts of a script. (Design by
        Yossi Gottlieb and Salvatore Sanfilippo, implemented by Salvatore)
* [NEW] Geo indexing support via GEOADD, GEORADIUS and other commands.
        See http://redis.io/commands/geoadd for more information.
        (Initially implemented in a fork of Redis called "Ardb".
         Matt Stancliff "imported back" the work to Redis and created the
         initial API and implementation. Salvatore Sanfilippo modified
         the API and the implementation, fixed bugs, improved performances
         and unified the duplicated code with t_zset.c)
* [NEW] Lua debugger. A complete stepping, remote debugger for Lua scripts.
        Video here: https://www.youtube.com/watch?v=IMvRfStaoyM
        (Salvatore Sanfilippo with many feedbacks and testing from
         Itamar Haber)
* [NEW] SDS improvements for speed and maximum string length.
        This makes Redis more memory efficient in different use cases.
        (Design and implementation by Oran Agra, some additional work
         by Salvatore Sanfilippo)
* [NEW] Modify Jemalloc size classes to make certain Redis objects fit
        better, improving memory efficiency. (Oran Agra)
* [NEW] Better consistency behavior between masters and slaves for expired
        keys. The slaves are only able to logically consider a key expired
        even before receiving the `DEL` command from the master. This avoids
        the delay there is sometimes between the natural expire of the key
        and the moment the slave is notified. (Salvatore Sanfilippo)
* [NEW] Support daemon supervision by upstart or systemd (Pierre-Yves Ritschard)
* [NEW] New encoding for the List type: Quicklists. Very important memory
        savings and storage space in RDB gains (up to 10x sometimes).
        (Design and implementation by Matt Stancliff. RDB storage reworked
         by Salvatore Sanfilippo)
* [NEW] SPOP with optional count argument. (Initial implementation by
        Alon Diamant, mostly reimplemented by Salvatore Sanfilippo for speed
        and in order to make the replication of a this class of commands,
        having as logical effect the execution of multiple commands, possible).
* [NEW] Support for RDB AUX fields. Now RDB files contain additional info
        like the creation date, version of Redis generating it and so forth.
        (Salvatore Sanfilippo)
* [NEW] Faster RDB loading via the RESIZEDB opcode to avoid useless hash tables
        rehashings. (Salvatore Sanfilippo)
* [NEW] HSTRLEN command. (@landmime and Salvatore Sanfilippo)
* [NEW] CONFIG SET/GET implementations refactored, partially rewritten,
        now exposing more config options. (Salvatore Sanfilippo)
* [NEW] CLUSTER NODES major speedup. (Salvatore Sanfilippo)
* [NEW] CLIENT KILL TYPE MASTER, to kill (disconnect) masters from slaves.
        (Salvatore Sanfilippo)
* [NEW] Jemalloc updated to 4.0.3 (Salvatore Sanfilippo)
* [NEW] DEBUG RESTART/CRASH-AND-RECOVER [delay] (Salvatore Sanfilippo)
* [NEW] CLIENT REPLY command implemented: ON, OFF and SKIP modes.
        (Salvatore Sanfilippo)
* [NEW] Crash report produced by Redis on crash improved. (Salvatore Sanfilippo)
* [NEW] Better memory test on crash. (Salvatore Sanfilippo)

Redis Cluster changes:

All the Redis Cluster changes in 3.2 were backported to 3.0, so there is
technically nothing new for now in this release. The most important things
are:

* Cluster rebalancing.
* A pipelined MIGRATE command which is 10x faster and makes resharding
  and rebalancing faster.
* Improved replicas migration.
* As a side effect of quicklists encoding (see above items), moving big
  lists between nodes is now a lot faster.

Redis Sentinel changes:

* [NEW] Sentinel connection sharing. Makes Sentinels able to scale to
        monitor many masters. (Salvatore Sanfilippo)
* [NEW] New SENTINEL INFO-CACHE command. (Matt Stancliff)
* More things backported to Redis 3.0 in the past, so no longer news of 3.2.

Migrating from 3.0 to 3.2
=========================

Redis 3.0 is mostly a strict subset of 3.2, you should not have any problem
upgrading your application from 3.0 to 3.2. However this is a list of small
non-backward compatible changes introduced in the 3.2 release:

* The default configuration file now binds to 127.0.0.1.
* Slaves try to no longer expose stale data about already expired keys.
* The RDB format changed. Redis 3.2 is still able to read 3.0 (and all the
  past versions) files, but not the other way around.
* Behavior on crash may be different. The crash log format changed and
  the memory test executed is now different.

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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.

Cheers,
Salvatore