Redis 6.0 正式版终于发布了！除了多线程还有什么新功能？

Redis 6.0.1 于 2020 年 5 月 2 日正式发布了，如 Redis 作者 antirez 所说，这是迄今为止最“企业”化的版本，也是有史以来改动最大的一个 Redis 版本，同时也是参与开发人数最多的一个版本。

所以在使用此版本之前，建议各位开发者先进行深入的测试再考虑投产，毕竟生产坏境无小事。好了，回到本文的重点，接下来我们来重点看下 Redis 6.0.1 给我们带来了那些新功能。

所以在使用此版本之前，建议各位开发者先进行深入的测试再考虑投产，毕竟生产坏境无小事。好了，回到本文的重点，接下来我们来重点看下 Redis 6.0.1 给我们带来了那些新功能。

Redis 新功能介绍

Redis 6 的更新日志，主要包含以下五部分的内容：

1. Redis 6.0-RC1 版新功能介绍；
2. Redis 6.0-RC2 版新功能介绍；
3. Redis 6.0-RC3 版新功能介绍；
4. Redis 6.0-RC4 版新功能介绍；
5. Redis 6.0.0 GA 版新功能介绍。

除了以上这些版本的更新日志外，还有 6.0.1 正式版的更新日志，不过这个正式版的发布时间只比 Redis 6.0.0 GA 晚了两天，因此只修复了一些 bug，所以我们只需要看以上五个日志即可。

1.Redis 6.0-rc1 更新日志

官方更新日志如下：

Redis 6 improves Redis in a number of key areas and is one of the largest

Redis releases in the history of the project, so here we'll list only

the biggest features in this release:

• The modules system now has a number of new APIs that allow module authors
  
    to make things otherwise not possible in the past. It is possible to
  
    store arbitrary module private data in RDB files, to hook on different
  
    server events, capture and rewrite commands executions, block clients on
  
    keys, and so forth.
• The Redis active expire cycle was rewritten for much faster eviction of keys
  
    that are already expired. Now the effort is tunable.
• Redis now supports SSL on all channels.
• ACL support, you can define users that can run only certain commands and/or
  
    can only access only certain keys patterns.
• Redis now supports a new protocol called RESP3, which returns more
  
    semantical replies: new clients using this protocol can understand just
  
    from the reply what type to return to the calling program.
• There is server-side support for client-side caching of key values. This
  
    feature is still experimental and will get more changes during the next
  
    release candidates, but you can already test it and read about it here:
  
    https://redis.io/topics/client-side-caching
• Redis can now optionally use threads to handle I/O, allowing to serve
  
    2 times as much operations per second in a single instance when
  
    pipelining cannot be used.
• Diskless replication is now supported even on replicas: a replica is now
  
    able, under certain conditions the user can configure, to load the RDB
  
    in the first synchronization directly from the socket to the memory.
• Redis-benchmark now supports a Redis Cluster mode.
• SRANDMEMBER and similar commands have a better distribution.
• Redis-cli improvements.
• Systemd support rewritten.
• A Redis Cluster proxy was released here:
  
    https://github.com/artix75/redis-cluster-proxy
• A Disque module for Redis was released here:
  
    https://github.com/antirez/disque-module

此版本新增的内容最大，如下列表所示：

• 众多新模块（modules）API
• 更好的过期循环（expire cycle）
• SSL
• ACLs 权限控制
• RESP3 协议
• 客户端缓存（Client side caching）
• 多线程 IO（Threaded I/O）
• 无盘复制副本（Diskless replication on replicas）
• Redis-benchmark 的集群支持和 redis-cli 优化
• 重写 Systemd 支持（Systemd support rewrite）
• Redis 集群代理与 Redis 6 一同发布（但在不同的 repo）
• Disque 模块与 Redis 6 一同发布

2.Redis 6.0-rc2 更新日志

Hi Redis users, Redis 6 is approaching and will be released 30th of April.

New release candidates will be released at the end of March, then another

one mid April, to finally reach the GA at the end of April.

Redis 6 RC2 brings many fixes and new things, especially in the area of

client side caching. This is the list of big changes in this release. As

usually you can find the full list of commits at the end:

New features and improvements:

• ACL LOG: log denied commands, keys accesses and authentications.
• Client side caching redesigned. Now we use keys not caching slots.
• Client side caching: Broadcasting mode implemented.
• Client side caching: OPTIN/OPTOUT modes implemented.
• Remove RDB files used for replication in persistence-less instances (option).

Fixes (only selected ones, see commits for all the fixes):

• Different fixes to streams in edge cases.
• Fix duplicated CLIENT SETNAME reply because of RESP3 changes.
• Fix crash due to new active expire division by zero.
• Avoid sentinel changes promoted_slave to be its own replica.
• Fix bug on KEYS command where pattern starts with * followed by \x00.
• Threaded I/O: now the main thread is used as well to do I/O.
• Many fixes to modules APIs, and more to come in the next RCs.
• ld2string should fail if string contains \0 in the middle.
• Make the Redis test more reliable.
• Fix SPOP returning nil (see #4709). WARNING: API change.

Redis 6 RC2 带来了许多修复和新功能，尤其是客户端的缓存功能，此版本的重大更改如下列表。

• ACL LOG：记录拒绝的命令，密钥访问和身份验证。
• 重新设计了客户端缓存。现在，我们使用密钥而不是缓存插槽。
• 客户端缓存：已实现广播模式。
• 客户端缓存：已实现 OPTIN/OPTOUT 模式。
• 删除用于在非持久性实例中进行复制的 RDB 文件（可选）。
• 修复程序（仅选定的修复程序，请参阅所有修复程序的提交）：
• 在边缘情况下对流的不同修复。
• 修正由于 RESP3 更改而导致重复的 CLIENT SETNAME 答复。
• 修正因新的有效到期除以零而导致的崩溃。
• 避免将哨兵更改提升为自己的副本。
• 修复了 KEYS 命令中以 * 开头，后跟 \x00 的错误。
• 线程 I/O：现在也使用主线程来执行 I/O。
• 对模块API进行了许多修复，而在下一个RC中还会有更多修复。
• 如果字符串中间包含 \0，则 ld2string 应该失败。
• 使 Redis 测试更可靠。

3.Redis 6.0-rc3 更新日志

Dear users, this is a list of the major changes in this release, please check 

the list of commits for detail:

• Fix crash due to refactoring for SSL, for the connection code.
• Precise timeouts for blocking commands. Now the timeouts have HZ
  
    resolution regardless of the number of connected clinets. New timeouts
  
    are stored in a radix tree and sorted by expire time.
• Fix rare crash when resizing the event loop because of CONFIG maxclients.
• Fix systemd readiness after successful partial resync.
• Redis-cli ask password mode to be prompted at startup (for additional safety).
• Keyspace notifications added to MIGRATE / RESTORE.
• Threaded I/O bugs fixed.
• Implement new ACL style AUTH in Sentinel.
• Make 'requirepass' more backward compatible with Redis <= 5.
• ACL: Handle default user as disabled if it's off regardless of "nopass".
• Fix a potential inconsistency when upgrading an instance in Redis Cluster
  
    and restarting it. The instance will act as a replica but will actually be
  
    set as a master immediately. However the choice of what to do with already
  
    expired keys, on loading, was made from the POV of replicas.
• Abort transactions after -READONLY error.
• Many different fixes to module APIs.
• BITFIELD_RO added to call the command on read only replicas.
• PSYNC2: meaningful offset implementation. Allow the disconnected master
  
    that is still sending PINGs to replicas, to be able to successfully
  
    PSYNC incrementally to new slaves, discarding the last part of the
  
    replication backlog consisting only of PINGs.
• Fix pipelined MULTI/EXEC during Lua scripts are in BUSY state.
• Re-fix propagation API in modules, broken again after other changes.

这个版本主要是修复了一些 bug，如下列表所示：

• 修复了由于重构 SSL 而导致的连接代码崩溃。
• 用于阻止命令的精确超时。现在超时已达到 HZ 分辨率，无论连接的 clinet 数量如何。新超时存储在基数树中并按到期时间排序。
• 修复了由于 CONFIG maxclients 而调整事件循环大小时发生的罕见崩溃。
• 修正部分重新同步成功后的 systemd 准备情况。
• Redis-cli 询问密码模式将在启动时提示（以提高安全性）。
• 键空间通知已添加到 MIGRATE/RESTORE。
• 修复了线程 I/O 错误。
• 在 Sentinel 中实现新的 ACL 样式 AUTH。
• 使 'requirepass' 与 Redis<=5 更向后兼容。
• ACL：如果默认用户关闭，则将其视为禁用状态，而不管其是否为“ nopass”。
• 修复了在 Redis 群集中升级实例时可能出现的不一致问题
• -READONLY 错误后中止事务。
• 对模块 API 的许多不同修复。
• 添加了 BITFIELD_RO 以在只读副本上调用该命令。
• PSYNC2：有意义的偏移量实现。允许断开连接的主机仍在向副本发送 PING，以便能够成功 PSYNC 以增量方式传递给新的从站，从而丢弃了仅由 PING 组成的复制积压。
• 修正 Lua 脚本处于繁忙状态时流水线的 MULTI/EXEC。
• 重新修复模块中的传播 API，在其他更改后再次中断。

4.Redis 6.0-rc4 更新日志

Hi all, this the latest release candidate of Redis 6. This is likely to

be very similar to what you'll see in Redis 6 GA. Please test it and

report any issue