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 2.6.6 ]
  18
  19 UPGRADE URGENCY: CRITICAL if you experienced one more more crashes.
  20                  MODERATE if Redis is running fine for you.
  21
  22 * [BUGFIX]   Jemalloc updated to 3.2.0.
  23
  24 --[ Redis 2.6.5 ]
  25
  26 UPGRADE URGENCY: MODERATE
  27
  28 Warning: this release of Redis introduces a different behavior in MULTI/EXEC
  29          handling of errors. This was done because the new behavior is safer
  30          compared to the old one, and should not break any code targeting
  31          Redis 2.6 in a critical way.
  32
  33          For more information check http://redis.io/topics/transactions
  34
  35 * [IMPROVED] RDB/AOF childern now log amount of additional memory used
  36              because of copy on write.
  37 * [BUGFIX]   MIGRATE non critical fixes (see commits for details).
  38 * [BUGFIX]   MULTI/EXEC: now EXEC aborts on errors before EXEC.
  39 * [BUGFIX]   Fix integer overflow in zunionInterGenericCommand resulting
  40              into Z[INTER|UNION][STORE] commands to crash under extremely
  41              unlikely conditions (almost impossible in real world).
  42 * [BUGFIX]   EVALSHA is now case insensitive (and will not crash).
  43
  44 --[ Redis 2.6.4 ]
  45
  46 UPGRADE URGENCY: LOW
  47
  48 * [IMPROVED] BSD license and copyright notice added to every .c and .h file.
  49
  50 --[ Redis 2.6.2 ]
  51
  52 UPGRADE URGENCY: LOW
  53
  54 * [BUGFIX]   The compilation fix for RHLE5 in 2.6.1 was broken. Fixed.
  55 * [IMPROVED] Linenoise updated, now supports Ctrl+w.
  56
  57 ---[ Redis 2.6.1 ]
  58
  59 UPGRADE URGENCY: LOW
  60
  61 * [BUGFIX]   Compilation on Linux < 2.6.17 or glibc < 2.6 fixed (RHLE5 & co).
  62
  63 ---[ Redis 2.6.0 ]
  64
  65 UPGRADE URGENCY: HIGH
  66
  67 * [BUGFIX]   Allow AUTH when server is in -BUSY state because of a slow script.
  68 * [BUGFIX]   MULTI/EXEC flow now makes sense when observed in MONITOR
  69 * [BUGFIX]   SCRIPT KILL now uses different error prefixes for different errors.
  70 * [BUGFIX]   Default memory limit for 32bit archs lowered from 3.5 to 3 GB.
  71 * [BUGFIX]   redis-check-dump is now compatible with RDB files generated by 2.6.
  72 * [IMPROVED] New field in INFO: slave_read_only.
  73
  74 ---[ Redis 2.5.14 (2.6 Release Candidate 8) ]
  75
  76 * [BUGFIX]   Fixed compilation on FreeBSD.
  77 * [IMPROVED] SRANDMEMBER <count> that returns multiple random elements.
  78 * [IMPROVED] Sentinel backported to 2.6. It will be taken in sync with 2.8.
  79 * [IMPROVED] Helper function for scripting to return errors and status replies.
  80 * [IMPROVED] SORT by nosort [ASC|DESC] uses sorted set elements ordering.
  81 * [BUGFIX]   Better resistence to system clock skew.
  82 * [IMPROVED] Warn the user when the configured maxmemory seems odd.
  83 * [BUGFIX]   Hashing function is now murmurhash2 for security purposes.
  84 * [IMPROVED] Install script no longer uses a template but redis.conf itself.
  85
  86 ---[ Redis 2.5.13 (2.6 Release Candidate 7) ]
  87
  88 UPGRADE URGENCY: HIGH
  89
  90 * [BUGFIX]   Theoretical bug in ziplist fixed.
  91 * [BUGFIX]   Better out of memory handling (Log produced in log file).
  92 * [BUGFIX]   Incrementally flush RDB file on slave side while performing the
  93              first synchronization with the master. This makes Redis less
  94              blocking in environments where disk I/O is slow.
  95 * [BUGFIX]   Don't crash with Lua's redis.call() without arguments.
  96 * [BUGFIX]   Don't crash after a big number of Lua calls on 32 bit systems
  97              because of a failed assertion.
  98 * [BUGFIX]   Fix SORT behaviour when called from scripting.
  99 * [BUGFIX]   Adjust slave PING period accordingly to REDIS_HZ define.
 100 * [BUGFIX]   BITCOUNT: fix crash on overflowing arguments.
 101 * [BUGFIX]   Return an error when SELECT argument is not an integer.
 102 * [BUGFIX]   Blocking operations on lists were completely reimplemented for
 103              correctness. Now blocking list ops and pushes originated from
 104              Lua scripts will play well together and will be replicated
 105              and transmitted to the AOF correctly.
 106 * [IMPROVED] Send async PING before starting replication to avoid blocking if
 107              master allows us to connect but it is actually not able to reply.
 108 * [IMPROVED] Support slave-priority for Redis Sentinel.
 109 * [IMPROVED] Hiredis library updated.
 110
 111 ---[ Redis 2.5.12 (2.6 Release Candidate 6) ]
 112
 113 UPGRADE URGENCY: MODERATE.
 114
 115 * [BUGFIX]   Fixed a timing attack on AUTH (Issue #560).
 116 * [BUGFIX]   Don't assume that "char" is signed.
 117 * [BUGFIX]   Check that we have connection before enabling pipe mode.
 118 * [BUGFIX]   Use the optimized version of the function to convert a double to
 119              its string representation. Compilation was disabled because of
 120              a typo in the #if statement.
 121 * [IMPROVED} REPLCONF internal command introduced, now INFO shows slaves with
 122              correct port numbers. This makes 2.5.12 Redis Sentinel compatible.
 123 * [IMPROVED] Truncate short write from the AOF for a cleaner restart. On short
 124              writes (for instance out of space) Redis will now try to remove
 125              the half-written data so that the next restart will work without
 126              the need for the "redis-check-aof" utility.
 127 * [IMPROVED] New in INFO: aof_last_bgrewrite_status
 128 * [IMPROVED] Allow Pub/Sub in contexts where other commands are blocked.
 129 * [BUGFIX]   mark fd as writable when EPOLLERR or EPOLLHUP is returned by
 130              epoll_wait.
 131
 132 ---[ Redis 2.5.11 (2.6 Release Candidate 5) ]
 133
 134 UPGRADE URGENCY: HIGH.
 135
 136 * [BUGFIX]   Fixed Hash corruption when loading an RDB file generated by
 137              previous versions of Redis that encoded hashes using
 138              a different ziplist encoding format for small integers.
 139              All the fileds that are integers in the range 0-255 may not
 140              be recognized, or duplicated un updates, causing a crash
 141              when the ziplist is converted to a real hash. (Issue #547).
 142 * [BUGFIX]   Fixed the count of memory used by output buffers in the
 143              setDeferredMultiBulkLength() function.
 144
 145 ---[ Redis 2.5.10 (2.6 Release Candidate 4) ]
 146
 147 UPGRADE URGENCY: HIGH.
 148
 149 * [BUGFIX]   Allow PREFIX to be overwritten on "make install".
 150 * [BUGFIX]   Run the test with just one client if the computer is slow.
 151 * [BUGFIX]   Event port support in our event driven libray.
 152 * [BUGFIX]   Jemalloc updated to 3.0.0. This fixes a possibly AOF rewrite issue.
 153              See https://github.com/antirez/redis/issues/504 for info.
 154 * [BUGFIX]   Fixed issue #516: ZINTERSTORE / ZUNIONSTORE with mixed sets/zsets.
 155 * [BUGFIX]   Set fd to writable when poll(2) detects POLLERR or POLLHUP event.
 156 * [BUGFIX]   Fixed RESTORE hash failure (Issue #532).
 157 * [IMPROVED] Allow an AOF rewrite buffer > 2GB (Related to issue #504).
 158 * [IMPROVED] Server cron function frequency is now configurable (REDIS_HZ).
 159 * [IMPROVED] Better, less blocking expired keys collection algorithm.
 160 * [FEATURE]  New commands: BITOP and BITCOUNT.
 161 * [FEATURE]  redis-cli --pipe for mass import.
 162
 163 What's new in Redis 2.5.9 (aka 2.6 Release Candidate 3)
 164 =======================================================
 165
 166 UPGRADE URGENCY: critical, upgrade ASAP.
 167
 168 * [BUGFIX] Fix for issue #500 (https://github.com/antirez/redis/pull/500).
 169            Redis 2.6-RC1 and RC2 may corrupt ziplist-encoded sorted sets
 170            produced by Redis 2.4.x.
 171 * [BUGFIX] Fixed several bugs in init.d script.
 172 * [BUGFIX] syncio.c functions modified for speed and correctness. On osx
 173            (and possibly other BSD-based systems) the slave would block on
 174            replication to send the SYNC command when the master was not
 175            available. This is fixed now, but was not affecting Linux installs.
 176 * Now when slave-serve-stale-data is set to yes and the master is down, instead
 177   of reporting a generic error Redis replies with -MASTERDOWN.
 178
 179 What's new in Redis 2.5.8 (aka 2.6 Release Candidate 2)
 180 =======================================================
 181
 182 UPGRADE URGENCY: high for all the users of the KEYS command, otherwise low.
 183
 184 * [BUGFIX] Fix for KEYS command: if the DB contains keys with expires the KEYS
 185            command may return the wrong output, having duplicated or missing
 186            keys. See issue #487 and #488 on github for details.
 187
 188 What's new in Redis 2.5.7 (aka 2.6 Release Candidate 1)
 189 =======================================================
 190
 191 UPGRADE URGENCY: upgrade not recommended because this is an RC release.
 192
 193 * This is the first release candidate for Redis 2.6. We are not aware of
 194   bugs, but part of this code is young and was never tested in production
 195   environments, so handle with care.
 196
 197 An overview of new features and changes in Redis 2.6.x
 198 ======================================================
 199
 200 * Server side Lua scripting, see http://redis.io/commands/eval
 201 * Virtual Memory removed (was deprecated in 2.4)
 202 * Hardcoded limits about max number of clients removed.
 203 * AOF low level semantics is generally more sane, and especially when used
 204   in slaves.
 205 * Milliseconds resolution expires, also added new commands with milliseconds
 206   precision (PEXPIRE, PTTL, ...).
 207 * Better memory usage for "small" lists, ziplists and hashes when fields or
 208   values contain small integers.
 209 * Read only slaves.
 210 * New bit opeations: BITCOUNT and BITOP commands.
 211 * Clients max output buffer soft and hard limits. You can specifiy different
 212   limits for different classes of clients (normal,pubsub,slave).
 213 * More incremental (less blocking) expired keys collection algorithm, in
 214   practical terms this means that Redis is more responsive when a very
 215   big number of keys expire about at the same time.
 216 * AOF is now able to rewrite aggregate data types using variadic commands,
 217   often producing an AOF that is faster to save, load, and is smaller in size.
 218 * Every redis.conf directive is now accepted as a command line option for the
 219   redis-server binary, with the same name and number of arguments.
 220 * Hash table seed randomization for protection against collisions attacks.
 221 * Performances improved when writing large objects to Redis.
 222 * Integrated memory test, see redis-server --test-memory.
 223 * INCRBYFLOAT and HINCRBYFLOAT commands.
 224 * New DUMP, RESTORE, MIGRATE commands (back ported from Redis Cluster to 2.6).
 225 * CRC64 checksump in RDB files.
 226 * Better MONITOR output and behavior (now commands are logged before execution).
 227 * "Software Watchdog" feature to debug latency issues.
 228 * Significant parts of the core refactored or rewritten. New internal APIs
 229   and core changes allowed to develop Redis Cluster on top of the new code,
 230   however for 2.6 all the cluster code was removed, and will be released with
 231   Redis 3.0 when it is more complete and stable.
 232 * Redis ASCII art logo added at startup.
 233 * Crash report on memory violation or failed asserts improved significantly
 234   to make debugging of hard to catch bugs simpler.
 235 * redis-benchmark improvements: ability to run selected tests,
 236   CSV output, faster, better help.
 237 * redis-cli improvements: --eval for comfortable development of Lua scripts.
 238 * SHUTDOWN now supports two optional arguments: "SAVE" and "NOSAVE".
 239 * INFO output split into sections, the command is now able to just show
 240   pecific sections.
 241 * New statistics about how many time a command was called, and how much
 242   execution time it used (INFO commandstats).
 243 * More predictable SORT behavior in edge cases.
 244 * Better support for big endian and *BSD systems.
 245 * Build system improved.
 246
 247 Migrating from 2.4 to 2.6
 248 =========================
 249
 250 Redis 2.4 is mostly a strict subset of 2.6. However there are a few things
 251 that you should be aware of:
 252
 253 * You can't use .rdb and AOF files generated with 2.6 into a 2.4 instance.
 254 * 2.6 slaves can be attached to 2.4 masters, but not the contrary, and only
 255   for the time needed to perform the version upgrade.
 256
 257 There are also a few API differences, that are unlikely to cause problems,
 258 but it is better to keep them in mind:
 259
 260 * SORT now will refuse to sort in numerical mode elements that can't be parsed
 261   as numbers.
 262 * EXPIREs now all have millisecond resolution (but this is very unlikely to
 263   break code that was not conceived exploting the previous resolution error
 264   in some way.)
 265 * INFO output is a bit different now, and contains empty lines and comments
 266   starting with '#'. All the major clients should be already fixed to work
 267   with the new INFO format.
 268 * Slaves are only read-only by default (but you can change this easily
 269   setting the "slave-read-only" configuration option to "no" editing your
 270   redis.conf or using CONFIG SET.
 271
 272 The following INFO fields were renamed for consistency:
 273
 274      changes_since_last_save -> rdb_changes_since_last_save
 275      bgsave_in_progress -> rdb_bgsave_in_progress
 276      last_save_time -> rdb_last_save_time
 277      last_bgsave_status -> rdb_last_bgsave_status
 278      bgrewriteaof_in_progress -> aof_rewrite_in_progress
 279      bgrewriteaof_scheduled -> aof_rewrite_scheduled
 280
 281 The following redis.conf and CONFIG GET / SET parameters changed:
 282
 283     * hash-max-zipmap-entries, now replaced by hash-max-ziplist-entries
 284     * hash-max-zipmap-value, now replaced by hash-max-ziplist-value
 285     * glueoutputbuf option was now completely removed (was deprecated)
 286
 287 --------------------------------------------------------------------------------
 288
 289 Credits: Where not specified the implementation and design are done by
 290 Salvatore Sanfilippo and Pieter Noordhuis. Thanks to VMware for making all
 291 this possible. Also many thanks to all the other contributors and the amazing
 292 community we have.
 293
 294 See commit messages for more credits.
 295
 296 Cheers,
 297 Salvatore