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 2.6.3 ]
  18
  19 * [BUGFIX]   Fixed 32 bit build on Linux systems.
  20 * [BUGFIX]   MONITOR and CLIENT LIST: propertly display unix socket clients.
  21 * [IMPROVED] redis-cli inline help updated.
  22 * [IMPROVED] Marginally more robust AOF child handling.
  23 * [IMPROVED] Fixed a few typos in comments.
  24
  25 $--[ Redis 2.6.2 ]
  26
  27 * [BUGFIX]   The compilation fix for RHLE5 in 2.6.1 was broken. Fixed.
  28 * [IMPROVED] Linenoise updated, now supports Ctrl+w.
  29
  30 ---[ Redis 2.6.1 ]
  31
  32 * [BUGFIX]   Compilation on Linux < 2.6.17 or glibc < 2.6 fixed (RHLE5 & co).
  33
  34 ---[ Redis 2.6.0 ]
  35
  36 * [BUGFIX]   Allow AUTH when server is in -BUSY state because of a slow script.
  37 * [BUGFIX]   MULTI/EXEC flow now makes sense when observed in MONITOR
  38 * [BUGFIX]   SCRIPT KILL now uses different error prefixes for different errors.
  39 * [BUGFIX]   Default memory limit for 32bit archs lowered from 3.5 to 3 GB.
  40 * [BUGFIX]   redis-check-dump is now compatible with RDB files generated by 2.6.
  41 * [IMPROVED] New field in INFO: slave_read_only.
  42
  43 ---[ Redis 2.5.14 (2.6 Release Candidate 8) ]
  44
  45 * [BUGFIX]   Fixed compilation on FreeBSD.
  46 * [IMPROVED] SRANDMEMBER <count> that returns multiple random elements.
  47 * [IMPROVED] Sentinel backported to 2.6. It will be taken in sync with 2.8.
  48 * [IMPROVED] Helper function for scripting to return errors and status replies.
  49 * [IMPROVED] SORT by nosort [ASC|DESC] uses sorted set elements ordering.
  50 * [BUGFIX]   Better resistence to system clock skew.
  51 * [IMPROVED] Warn the user when the configured maxmemory seems odd.
  52 * [BUGFIX]   Hashing function is now murmurhash2 for security purposes.
  53 * [IMPROVED] Install script no longer uses a template but redis.conf itself.
  54
  55 ---[ Redis 2.5.13 (2.6 Release Candidate 7) ]
  56
  57 UPGRADE URGENCY: HIGH
  58
  59 * [BUGFIX]   Theoretical bug in ziplist fixed.
  60 * [BUGFIX]   Better out of memory handling (Log produced in log file).
  61 * [BUGFIX]   Incrementally flush RDB file on slave side while performing the
  62              first synchronization with the master. This makes Redis less
  63              blocking in environments where disk I/O is slow.
  64 * [BUGFIX]   Don't crash with Lua's redis.call() without arguments.
  65 * [BUGFIX]   Don't crash after a big number of Lua calls on 32 bit systems
  66              because of a failed assertion.
  67 * [BUGFIX]   Fix SORT behaviour when called from scripting.
  68 * [BUGFIX]   Adjust slave PING period accordingly to REDIS_HZ define.
  69 * [BUGFIX]   BITCOUNT: fix crash on overflowing arguments.
  70 * [BUGFIX]   Return an error when SELECT argument is not an integer.
  71 * [BUGFIX]   Blocking operations on lists were completely reimplemented for
  72              correctness. Now blocking list ops and pushes originated from
  73              Lua scripts will play well together and will be replicated
  74              and transmitted to the AOF correctly.
  75 * [IMPROVED] Send async PING before starting replication to avoid blocking if
  76              master allows us to connect but it is actually not able to reply.
  77 * [IMPROVED] Support slave-priority for Redis Sentinel.
  78 * [IMPROVED] Hiredis library updated.
  79
  80 ---[ Redis 2.5.12 (2.6 Release Candidate 6) ]
  81
  82 UPGRADE URGENCY: MODERATE.
  83
  84 * [BUGFIX]   Fixed a timing attack on AUTH (Issue #560).
  85 * [BUGFIX]   Don't assume that "char" is signed.
  86 * [BUGFIX]   Check that we have connection before enabling pipe mode.
  87 * [BUGFIX]   Use the optimized version of the function to convert a double to
  88              its string representation. Compilation was disabled because of
  89              a typo in the #if statement.
  90 * [IMPROVED} REPLCONF internal command introduced, now INFO shows slaves with
  91              correct port numbers. This makes 2.5.12 Redis Sentinel compatible.
  92 * [IMPROVED] Truncate short write from the AOF for a cleaner restart. On short
  93              writes (for instance out of space) Redis will now try to remove
  94              the half-written data so that the next restart will work without
  95              the need for the "redis-check-aof" utility.
  96 * [IMPROVED] New in INFO: aof_last_bgrewrite_status
  97 * [IMPROVED] Allow Pub/Sub in contexts where other commands are blocked.
  98 * [BUGFIX]   mark fd as writable when EPOLLERR or EPOLLHUP is returned by
  99              epoll_wait.
 100
 101 ---[ Redis 2.5.11 (2.6 Release Candidate 5) ]
 102
 103 UPGRADE URGENCY: HIGH.
 104
 105 * [BUGFIX]   Fixed Hash corruption when loading an RDB file generated by
 106              previous versions of Redis that encoded hashes using
 107              a different ziplist encoding format for small integers.
 108              All the fileds that are integers in the range 0-255 may not
 109              be recognized, or duplicated un updates, causing a crash
 110              when the ziplist is converted to a real hash. (Issue #547).
 111 * [BUGFIX]   Fixed the count of memory used by output buffers in the
 112              setDeferredMultiBulkLength() function.
 113
 114 ---[ Redis 2.5.10 (2.6 Release Candidate 4) ]
 115
 116 UPGRADE URGENCY: HIGH.
 117
 118 * [BUGFIX]   Allow PREFIX to be overwritten on "make install".
 119 * [BUGFIX]   Run the test with just one client if the computer is slow.
 120 * [BUGFIX]   Event port support in our event driven libray.
 121 * [BUGFIX]   Jemalloc updated to 3.0.0. This fixes a possibly AOF rewrite issue.
 122              See https://github.com/antirez/redis/issues/504 for info.
 123 * [BUGFIX]   Fixed issue #516: ZINTERSTORE / ZUNIONSTORE with mixed sets/zsets.
 124 * [BUGFIX]   Set fd to writable when poll(2) detects POLLERR or POLLHUP event.
 125 * [BUGFIX]   Fixed RESTORE hash failure (Issue #532).
 126 * [IMPROVED] Allow an AOF rewrite buffer > 2GB (Related to issue #504).
 127 * [IMPROVED] Server cron function frequency is now configurable (REDIS_HZ).
 128 * [IMPROVED] Better, less blocking expired keys collection algorithm.
 129 * [FEATURE]  New commands: BITOP and BITCOUNT.
 130 * [FEATURE]  redis-cli --pipe for mass import.
 131
 132 What's new in Redis 2.5.9 (aka 2.6 Release Candidate 3)
 133 =======================================================
 134
 135 UPGRADE URGENCY: critical, upgrade ASAP.
 136
 137 * [BUGFIX] Fix for issue #500 (https://github.com/antirez/redis/pull/500).
 138            Redis 2.6-RC1 and RC2 may corrupt ziplist-encoded sorted sets
 139            produced by Redis 2.4.x.
 140 * [BUGFIX] Fixed several bugs in init.d script.
 141 * [BUGFIX] syncio.c functions modified for speed and correctness. On osx
 142            (and possibly other BSD-based systems) the slave would block on
 143            replication to send the SYNC command when the master was not
 144            available. This is fixed now, but was not affecting Linux installs.
 145 * Now when slave-serve-stale-data is set to yes and the master is down, instead
 146   of reporting a generic error Redis replies with -MASTERDOWN.
 147
 148 What's new in Redis 2.5.8 (aka 2.6 Release Candidate 2)
 149 =======================================================
 150
 151 UPGRADE URGENCY: high for all the users of the KEYS command, otherwise low.
 152
 153 * [BUGFIX] Fix for KEYS command: if the DB contains keys with expires the KEYS
 154            command may return the wrong output, having duplicated or missing
 155            keys. See issue #487 and #488 on github for details.
 156
 157 What's new in Redis 2.5.7 (aka 2.6 Release Candidate 1)
 158 =======================================================
 159
 160 UPGRADE URGENCY: upgrade not recommended because this is an RC release.
 161
 162 * This is the first release candidate for Redis 2.6. We are not aware of
 163   bugs, but part of this code is young and was never tested in production
 164   environments, so handle with care.
 165
 166 An overview of new features and changes in Redis 2.6.x
 167 ======================================================
 168
 169 * Server side Lua scripting, see http://redis.io/commands/eval
 170 * Virtual Memory removed (was deprecated in 2.4)
 171 * Hardcoded limits about max number of clients removed.
 172 * AOF low level semantics is generally more sane, and especially when used
 173   in slaves.
 174 * Milliseconds resolution expires, also added new commands with milliseconds
 175   precision (PEXPIRE, PTTL, ...).
 176 * Better memory usage for "small" lists, ziplists and hashes when fields or
 177   values contain small integers.
 178 * Read only slaves.
 179 * New bit opeations: BITCOUNT and BITOP commands.
 180 * Clients max output buffer soft and hard limits. You can specifiy different
 181   limits for different classes of clients (normal,pubsub,slave).
 182 * More incremental (less blocking) expired keys collection algorithm, in
 183   practical terms this means that Redis is more responsive when a very
 184   big number of keys expire about at the same time.
 185 * AOF is now able to rewrite aggregate data types using variadic commands,
 186   often producing an AOF that is faster to save, load, and is smaller in size.
 187 * Every redis.conf directive is now accepted as a command line option for the
 188   redis-server binary, with the same name and number of arguments.
 189 * Hash table seed randomization for protection against collisions attacks.
 190 * Performances improved when writing large objects to Redis.
 191 * Integrated memory test, see redis-server --test-memory.
 192 * INCRBYFLOAT and HINCRBYFLOAT commands.
 193 * New DUMP, RESTORE, MIGRATE commands (back ported from Redis Cluster to 2.6).
 194 * CRC64 checksump in RDB files.
 195 * Better MONITOR output and behavior (now commands are logged before execution).
 196 * "Software Watchdog" feature to debug latency issues.
 197 * Significant parts of the core refactored or rewritten. New internal APIs
 198   and core changes allowed to develop Redis Cluster on top of the new code,
 199   however for 2.6 all the cluster code was removed, and will be released with
 200   Redis 3.0 when it is more complete and stable.
 201 * Redis ASCII art logo added at startup.
 202 * Crash report on memory violation or failed asserts improved significantly
 203   to make debugging of hard to catch bugs simpler.
 204 * redis-benchmark improvements: ability to run selected tests,
 205   CSV output, faster, better help.
 206 * redis-cli improvements: --eval for comfortable development of Lua scripts.
 207 * SHUTDOWN now supports two optional arguments: "SAVE" and "NOSAVE".
 208 * INFO output split into sections, the command is now able to just show
 209   pecific sections.
 210 * New statistics about how many time a command was called, and how much
 211   execution time it used (INFO commandstats).
 212 * More predictable SORT behavior in edge cases.
 213 * Better support for big endian and *BSD systems.
 214 * Build system improved.
 215
 216 Migrating from 2.4 to 2.6
 217 =========================
 218
 219 Redis 2.4 is mostly a strict subset of 2.6. However there are a few things
 220 that you should be aware of:
 221
 222 * You can't use .rdb and AOF files generated with 2.6 into a 2.4 instance.
 223 * 2.6 slaves can be attached to 2.4 masters, but not the contrary, and only
 224   for the time needed to perform the version upgrade.
 225
 226 There are also a few API differences, that are unlikely to cause problems,
 227 but it is better to keep them in mind:
 228
 229 * SORT now will refuse to sort in numerical mode elements that can't be parsed
 230   as numbers.
 231 * EXPIREs now all have millisecond resolution (but this is very unlikely to
 232   break code that was not conceived exploting the previous resolution error
 233   in some way.)
 234 * INFO output is a bit different now, and contains empty lines and comments
 235   starting with '#'. All the major clients should be already fixed to work
 236   with the new INFO format.
 237 * Slaves are only read-only by default (but you can change this easily
 238   setting the "slave-read-only" configuration option to "no" editing your
 239   redis.conf or using CONFIG SET.
 240
 241 The following INFO fields were renamed for consistency:
 242
 243      changes_since_last_save -> rdb_changes_since_last_save
 244      bgsave_in_progress -> rdb_bgsave_in_progress
 245      last_save_time -> rdb_last_save_time
 246      last_bgsave_status -> rdb_last_bgsave_status
 247      bgrewriteaof_in_progress -> aof_rewrite_in_progress
 248      bgrewriteaof_scheduled -> aof_rewrite_scheduled
 249
 250 The following redis.conf and CONFIG GET / SET parameters changed:
 251
 252     * hash-max-zipmap-entries, now replaced by hash-max-ziplist-entries
 253     * hash-max-zipmap-value, now replaced by hash-max-ziplist-value
 254     * glueoutputbuf option was now completely removed (was deprecated)
 255
 256 --------------------------------------------------------------------------------
 257
 258 Credits: Where not specified the implementation and design are done by
 259 Salvatore Sanfilippo and Pieter Noordhuis. Thanks to VMware for making all
 260 this possible. Also many thanks to all the other contributors and the amazing
 261 community we have.
 262
 263 See commit messages for more credits.
 264
 265 Cheers,
 266 Salvatore