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 --------------------------------------------------------------------------------
   9 Upgrade urgency levels:
  10
  11 LOW:      No need to upgrade unless there are new features you want to use.
  12 MODERATE: Program an upgrade of the server, but it's not urgent.
  13 HIGH:     There is a critical bug that may affect a subset of users. Upgrade!
  14 CRITICAL: There is a critical bug affecting MOST USERS. Upgrade ASAP.
  15 --------------------------------------------------------------------------------
  16
  17 ---[ Redis 2.5.14 (2.6 Release Candidate 8) ]
  18
  19 * [BUGFIX]   Fixed compilation on FreeBSD.
  20 * [IMPROVED] SRANDMEMBER <count> that returns multiple random elements.
  21 * [IMPROVED] Sentinel backported to 2.6. It will be taken in sync with 2.8.
  22 * [IMPROVED] Helper function for scripting to return errors and status replies.
  23 * [IMPROVED] SORT by nosort [ASC|DESC] uses sorted set elements ordering.
  24 * [BUGFIX]   Better resistence to system clock skew.
  25 * [IMPROVED] Warn the user when the configured maxmemory seems odd.
  26 * [BUGFIX]   Hashing function is now murmurhash2 for security purposes.
  27 * [IMPROVED] Install script no longer uses a template but redis.conf itself.
  28
  29 ---[ Redis 2.5.13 (2.6 Release Candidate 7) ]
  30
  31 UPGRADE URGENCY: HIGH
  32
  33 * [BUGFIX]   Theoretical bug in ziplist fixed.
  34 * [BUGFIX]   Better out of memory handling (Log produced in log file).
  35 * [BUGFIX]   Incrementally flush RDB file on slave side while performing the
  36              first synchronization with the master. This makes Redis less
  37              blocking in environments where disk I/O is slow.
  38 * [BUGFIX]   Don't crash with Lua's redis.call() without arguments.
  39 * [BUGFIX]   Don't crash after a big number of Lua calls on 32 bit systems
  40              because of a failed assertion.
  41 * [BUGFIX]   Fix SORT behaviour when called from scripting.
  42 * [BUGFIX]   Adjust slave PING period accordingly to REDIS_HZ define.
  43 * [BUGFIX]   BITCOUNT: fix crash on overflowing arguments.
  44 * [BUGFIX]   Return an error when SELECT argument is not an integer.
  45 * [BUGFIX]   Blocking operations on lists were completely reimplemented for
  46              correctness. Now blocking list ops and pushes originated from
  47              Lua scripts will play well together and will be replicated
  48              and transmitted to the AOF correctly.
  49 * [IMPROVED] Send async PING before starting replication to avoid blocking if
  50              master allows us to connect but it is actually not able to reply.
  51 * [IMPROVED] Support slave-priority for Redis Sentinel.
  52 * [IMPROVED] Hiredis library updated.
  53
  54 ---[ Redis 2.5.12 (2.6 Release Candidate 6) ]
  55
  56 UPGRADE URGENCY: MODERATE.
  57
  58 * [BUGFIX]   Fixed a timing attack on AUTH (Issue #560).
  59 * [BUGFIX]   Don't assume that "char" is signed.
  60 * [BUGFIX]   Check that we have connection before enabling pipe mode.
  61 * [BUGFIX]   Use the optimized version of the function to convert a double to
  62              its string representation. Compilation was disabled because of
  63              a typo in the #if statement.
  64 * [IMPROVED} REPLCONF internal command introduced, now INFO shows slaves with
  65              correct port numbers. This makes 2.5.12 Redis Sentinel compatible.
  66 * [IMPROVED] Truncate short write from the AOF for a cleaner restart. On short
  67              writes (for instance out of space) Redis will now try to remove
  68              the half-written data so that the next restart will work without
  69              the need for the "redis-check-aof" utility.
  70 * [IMPROVED] New in INFO: aof_last_bgrewrite_status
  71 * [IMPROVED] Allow Pub/Sub in contexts where other commands are blocked.
  72 * [BUGFIX]   mark fd as writable when EPOLLERR or EPOLLHUP is returned by
  73              epoll_wait.
  74
  75 ---[ Redis 2.5.11 (2.6 Release Candidate 5) ]
  76
  77 UPGRADE URGENCY: HIGH.
  78
  79 * [BUGFIX]   Fixed Hash corruption when loading an RDB file generated by
  80              previous versions of Redis that encoded hashes using
  81              a different ziplist encoding format for small integers.
  82              All the fileds that are integers in the range 0-255 may not
  83              be recognized, or duplicated un updates, causing a crash
  84              when the ziplist is converted to a real hash. (Issue #547).
  85 * [BUGFIX]   Fixed the count of memory used by output buffers in the
  86              setDeferredMultiBulkLength() function.
  87
  88 ---[ Redis 2.5.10 (2.6 Release Candidate 4) ]
  89
  90 UPGRADE URGENCY: HIGH.
  91
  92 * [BUGFIX]   Allow PREFIX to be overwritten on "make install".
  93 * [BUGFIX]   Run the test with just one client if the computer is slow.
  94 * [BUGFIX]   Event port support in our event driven libray.
  95 * [BUGFIX]   Jemalloc updated to 3.0.0. This fixes a possibly AOF rewrite issue.
  96              See https://github.com/antirez/redis/issues/504 for info.
  97 * [BUGFIX]   Fixed issue #516: ZINTERSTORE / ZUNIONSTORE with mixed sets/zsets.
  98 * [BUGFIX]   Set fd to writable when poll(2) detects POLLERR or POLLHUP event.
  99 * [BUGFIX]   Fixed RESTORE hash failure (Issue #532).
 100 * [IMPROVED] Allow an AOF rewrite buffer > 2GB (Related to issue #504).
 101 * [IMPROVED] Server cron function frequency is now configurable (REDIS_HZ).
 102 * [IMPROVED] Better, less blocking expired keys collection algorithm.
 103 * [FEATURE]  New commands: BITOP and BITCOUNT.
 104 * [FEATURE]  redis-cli --pipe for mass import.
 105
 106 What's new in Redis 2.5.9 (aka 2.6 Release Candidate 3)
 107 =======================================================
 108
 109 UPGRADE URGENCY: critical, upgrade ASAP.
 110
 111 * [BUGFIX] Fix for issue #500 (https://github.com/antirez/redis/pull/500).
 112            Redis 2.6-RC1 and RC2 may corrupt ziplist-encoded sorted sets
 113            produced by Redis 2.4.x.
 114 * [BUGFIX] Fixed several bugs in init.d script.
 115 * [BUGFIX] syncio.c functions modified for speed and correctness. On osx
 116            (and possibly other BSD-based systems) the slave would block on
 117            replication to send the SYNC command when the master was not
 118            available. This is fixed now, but was not affecting Linux installs.
 119 * Now when slave-serve-stale-data is set to yes and the master is down, instead
 120   of reporting a generic error Redis replies with -MASTERDOWN.
 121
 122 What's new in Redis 2.5.8 (aka 2.6 Release Candidate 2)
 123 =======================================================
 124
 125 UPGRADE URGENCY: high for all the users of the KEYS command, otherwise low.
 126
 127 * [BUGFIX] Fix for KEYS command: if the DB contains keys with expires the KEYS
 128            command may return the wrong output, having duplicated or missing
 129            keys. See issue #487 and #488 on github for details.
 130
 131 What's new in Redis 2.5.7 (aka 2.6 Release Candidate 1)
 132 =======================================================
 133
 134 UPGRADE URGENCY: upgrade not recommended because this is an RC release.
 135
 136 * This is the first release candidate for Redis 2.6. We are not aware of
 137   bugs, but part of this code is young and was never tested in production
 138   environments, so handle with care.
 139
 140 An overview of new features and changes in Redis 2.6.x
 141 ======================================================
 142
 143 * Server side Lua scripting, see http://redis.io/commands/eval
 144 * Virtual Memory removed (was deprecated in 2.4)
 145 * Hardcoded limits about max number of clients removed.
 146 * AOF low level semantics is generally more sane, and especially when used
 147   in slaves.
 148 * Milliseconds resolution expires, also added new commands with milliseconds
 149   precision (PEXPIRE, PTTL, ...).
 150 * Better memory usage for "small" lists, ziplists and hashes when fields or
 151   values contain small integers.
 152 * Read only slaves.
 153 * New bit opeations: BITCOUNT and BITOP commands.
 154 * Clients max output buffer soft and hard limits. You can specifiy different
 155   limits for different classes of clients (normal,pubsub,slave).
 156 * More incremental (less blocking) expired keys collection algorithm, in
 157   practical terms this means that Redis is more responsive when a very
 158   big number of keys expire about at the same time.
 159 * AOF is now able to rewrite aggregate data types using variadic commands,
 160   often producing an AOF that is faster to save, load, and is smaller in size.
 161 * Every redis.conf directive is now accepted as a command line option for the
 162   redis-server binary, with the same name and number of arguments.
 163 * Hash table seed randomization for protection against collisions attacks.
 164 * Performances improved when writing large objects to Redis.
 165 * Integrated memory test, see redis-server --test-memory.
 166 * INCRBYFLOAT and HINCRBYFLOAT commands.
 167 * New DUMP, RESTORE, MIGRATE commands (back ported from Redis Cluster to 2.6).
 168 * CRC64 checksump in RDB files.
 169 * Better MONITOR output and behavior (now commands are logged before execution).
 170 * "Software Watchdog" feature to debug latency issues.
 171 * Significant parts of the core refactored or rewritten. New internal APIs
 172   and core changes allowed to develop Redis Cluster on top of the new code,
 173   however for 2.6 all the cluster code was removed, and will be released with
 174   Redis 3.0 when it is more complete and stable.
 175 * Redis ASCII art logo added at startup.
 176 * Crash report on memory violation or failed asserts improved significantly
 177   to make debugging of hard to catch bugs simpler.
 178 * redis-benchmark improvements: ability to run selected tests,
 179   CSV output, faster, better help.
 180 * redis-cli improvements: --eval for comfortable development of Lua scripts.
 181 * SHUTDOWN now supports two optional arguments: "SAVE" and "NOSAVE".
 182 * INFO output split into sections, the command is now able to just show
 183   pecific sections.
 184 * New statistics about how many time a command was called, and how much
 185   execution time it used (INFO commandstats).
 186 * More predictable SORT behavior in edge cases.
 187 * Better support for big endian and *BSD systems.
 188 * Build system improved.
 189
 190 Migrating from 2.4 to 2.6
 191 =========================
 192
 193 Redis 2.4 is mostly a strict subset of 2.6. However there are a few things
 194 that you should be aware of:
 195
 196 * You can't use .rdb and AOF files generated with 2.6 into a 2.4 instance.
 197 * 2.6 slaves can be attached to 2.4 masters, but not the contrary, and only
 198   for the time needed to perform the version upgrade.
 199
 200 There are also a few API differences, that are unlikely to cause problems,
 201 but it is better to keep them in mind:
 202
 203 * SORT now will refuse to sort in numerical mode elements that can't be parsed
 204   as numbers.
 205 * EXPIREs now all have millisecond resolution (but this is very unlikely to
 206   break code that was not conceived exploting the previous resolution error
 207   in some way.)
 208 * INFO output is a bit different now, and contains empty lines and comments
 209   starting with '#'. All the major clients should be already fixed to work
 210   with the new INFO format.
 211 * Slaves are only read-only by default (but you can change this easily
 212   setting the "slave-read-only" configuration option to "no" editing your
 213   redis.conf or using CONFIG SET.
 214
 215 The following INFO fields were renamed for consistency:
 216
 217      changes_since_last_save -> rdb_changes_since_last_save
 218      bgsave_in_progress -> rdb_bgsave_in_progress
 219      last_save_time -> rdb_last_save_time
 220      last_bgsave_status -> rdb_last_bgsave_status
 221      bgrewriteaof_in_progress -> aof_rewrite_in_progress
 222      bgrewriteaof_scheduled -> aof_rewrite_scheduled
 223
 224 The following redis.conf and CONFIG GET / SET parameters changed:
 225
 226     * hash-max-zipmap-entries, now replaced by hash-max-ziplist-entries
 227     * hash-max-zipmap-value, now replaced by hash-max-ziplist-value
 228     * glueoutputbuf option was now completely removed (was deprecated)
 229
 230 --------------------------------------------------------------------------------
 231
 232 Credits: Where not specified the implementation and design are done by
 233 Salvatore Sanfilippo and Pieter Noordhuis. Thanks to VMware for making all
 234 this possible. Also many thanks to all the other contributors and the amazing
 235 community we have.
 236
 237 See commit messages for more credits.
 238
 239 Cheers,
 240 Salvatore