00-RELEASENOTES

   1 Redis 2.6 release notes
   2 =======================
   3
   4 ** IMPORTANT ** Check the 'Migrating from 2.4 to 2.6' section at the end of
   5                 this file for information about what changed between 2.4 and
   6                 2.6 and how this may affect your application.
   7
   8 What's new in Redis 2.5.9 (aka 2.6 Release Candidate 3)
   9 =======================================================
  10
  11 UPGRADE URGENCY: critical, upgrade ASAP.
  12
  13 * [BUGFIX] Fix for issue #500 (https://github.com/antirez/redis/pull/500).
  14            Redis 2.6-RC1 and RC2 may corrupt ziplist-encoded sorted sets
  15            produced by Redis 2.4.x.
  16 * [BUGFIX] Fixed several bugs in init.d script.
  17 * [BUGFIX] syncio.c functions modified for speed and correctness. On osx
  18            (and possibly other BSD-based systems) the slave would block on
  19            replication to send the SYNC command when the master was not
  20            available. This is fixed now, but was not affecting Linux installs.
  21 * Now when slave-serve-stale-data is set to yes and the master is down, instead
  22   of reporting a generic error Redis replies with -MASTERDOWN.
  23
  24 What's new in Redis 2.5.8 (aka 2.6 Release Candidate 2)
  25 =======================================================
  26
  27 UPGRADE URGENCY: high for all the users of the KEYS command, otherwise low.
  28
  29 * [BUGFIX] Fix for KEYS command: if the DB contains keys with expires the KEYS
  30            command may return the wrong output, having duplicated or missing
  31            keys. See issue #487 and #488 on github for details.
  32
  33 What's new in Redis 2.5.7 (aka 2.6 Release Candidate 1)
  34 =======================================================
  35
  36 UPGRADE URGENCY: upgrade not recommended because this is an RC release.
  37
  38 * This is the first release candidate for Redis 2.6. We are not aware of
  39   bugs, but part of this code is young and was never tested in production
  40   environments, so handle with care.
  41
  42 An overview of new features and changes in Redis 2.6.x
  43 ======================================================
  44
  45 * Server side Lua scripting, see http://redis.io/commands/eval
  46 * Virtual Memory removed (was deprecated in 2.4)
  47 * Hardcoded limits about max number of clients removed.
  48 * AOF low level semantics is generally more sane, and especially when used
  49   in slaves.
  50 * Milliseconds resolution expires, also added new commands with milliseconds
  51   precision (PEXPIRE, PTTL, ...).
  52 * Better memory usage for "small" lists, ziplists and hashes when fields or
  53   values contain small integers.
  54 * Read only slaves.
  55 * New bit opeations: BITCOUNT and BITOP commands.
  56 * Clients max output buffer soft and hard limits. You can specifiy different
  57   limits for different classes of clients (normal,pubsub,slave).
  58 * More incremental (less blocking) expired keys collection algorithm, in
  59   practical terms this means that Redis is more responsive when a very
  60   big number of keys expire about at the same time.
  61 * AOF is now able to rewrite aggregate data types using variadic commands,
  62   often producing an AOF that is faster to save, load, and is smaller in size.
  63 * Every redis.conf directive is now accepted as a command line option for the
  64   redis-server binary, with the same name and number of arguments.
  65 * Hash table seed randomization for protection against collisions attacks.
  66 * Performances improved when writing large objects to Redis.
  67 * Integrated memory test, see redis-server --test-memory.
  68 * INCRBYFLOAT and HINCRBYFLOAT commands.
  69 * New DUMP, RESTORE, MIGRATE commands (back ported from Redis Cluster to 2.6).
  70 * CRC64 checksump in RDB files.
  71 * Better MONITOR output and behavior (now commands are logged before execution).
  72 * "Software Watchdog" feature to debug latency issues.
  73 * Significant parts of the core refactored or rewritten. New internal APIs
  74   and core changes allowed to develop Redis Cluster on top of the new code,
  75   however for 2.6 all the cluster code was removed, and will be released with
  76   Redis 3.0 when it is more complete and stable.
  77 * Redis ASCII art logo added at startup.
  78 * Crash report on memory violation or failed asserts improved significantly
  79   to make debugging of hard to catch bugs simpler.
  80 * redis-benchmark improvements: ability to run selected tests,
  81   CSV output, faster, better help.
  82 * redis-cli improvements: --eval for comfortable development of Lua scripts.
  83 * SHUTDOWN now supports two optional arguments: "SAVE" and "NOSAVE".
  84 * INFO output split into sections, the command is now able to just show
  85   pecific sections.
  86 * New statistics about how many time a command was called, and how much
  87   execution time it used (INFO commandstats).
  88 * More predictable SORT behavior in edge cases.
  89 * Better support for big endian and *BSD systems.
  90 * Build system improved.
  91
  92 Migrating from 2.4 to 2.6
  93 =========================
  94
  95 Redis 2.4 is mostly a strict subset of 2.6. However there are a few things
  96 that you should be aware of:
  97
  98 * You can't use .rdb and AOF files generated with 2.6 into a 2.4 instance.
  99 * 2.4 slaves can be attached to 2.6 masters, but not the contrary, and only
 100   for the time needed to perform the version upgrade.
 101
 102 There are also a few API differences, that are unlikely to cause problems,
 103 but it is better to keep them in mind:
 104
 105 * SORT now will refuse to sort in numerical mode elements that can't be parsed
 106   as numbers.
 107 * EXPIREs now all have millisecond resolution (but this is very unlikely to
 108   break code that was not conceived exploting the previous resolution error
 109   in some way.)
 110 * INFO output is a bit different now, and contains empty lines and comments
 111   starting with '#'. All the major clients should be already fixed to work
 112   with the new INFO format.
 113 * Slaves are only read-only by default (but you can change this easily
 114   setting the "slave-read-only" configuration option to "no" editing your
 115   redis.conf or using CONFIG SET.
 116
 117 The following INFO fields were renamed for consistency:
 118
 119      changes_since_last_save -> rdb_changes_since_last_save
 120      bgsave_in_progress -> rdb_bgsave_in_progress
 121      last_save_time -> rdb_last_save_time
 122      last_bgsave_status -> rdb_last_bgsave_status
 123      bgrewriteaof_in_progress -> aof_rewrite_in_progress
 124      bgrewriteaof_scheduled -> aof_rewrite_scheduled
 125
 126 The following redis.conf and CONFIG GET / SET parameters changed:
 127
 128     * hash-max-zipmap-entries, now replaced by hash-max-ziplist-entries
 129     * hash-max-zipmap-value, now replaced by hash-max-ziplist-value
 130     * glueoutputbuf option was now completely removed (was deprecated)
 131
 132 --------------------------------------------------------------------------------
 133
 134 Credits: Where not specified the implementation and design are done by
 135 Salvatore Sanfilippo and Pieter Noordhuis. Thanks to VMware for making all
 136 this possible. Also many thanks to all the other contributors and the amazing
 137 community we have.
 138
 139 See commit messages for more credits.
 140
 141 Cheers,
 142 Salvatore