Redis 3.2.0 new-1.对比3.0

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一、Redis3.0与3.2文件对比

1. clone redis

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git clone https://github.com/antirez/redis.git

2. checkout分支

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cd redis
git checkout 3.0
git checkout 3.2

3. 比较

(1) 比较3.0和3.2文件变化数

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> git rev-list 3.0..3.2 --count
1708

(2) 比较3.0和3.2文件变化统计

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> git diff 3.0..3.2 --shortstat
比较3.0和3.2文件变化数

二、Redis3.0与3.2默认配置文件变化

1.配置变化

配置变化

Redis3.2添加了两个配置：

  • protected-mode yes
  • supervised no

Redis3.2修改了两个配置：
有关list的优化，由(1)改为(2)，虽然还没详细了解，应该是list的底层数据结构做了一些新的变化或者优化。

配置一：

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list-max-ziplist-entries 512
list-max-ziplist-value 64

配置二：

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list-max-ziplist-size -2
list-compress-depth 0

配置三：

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bind 127.0.0.1

bind在Redis3.2.0中默认改为127.0.0.1

2.新配置说明

  • (1).protected-mode(默认是yes)
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    # Protected mode is a layer of security protection, in order to avoid that
    # Redis instances left open on the internet are accessed and exploited.
    #
    # When protected mode is on and if:
    #
    # 1) The server is not binding explicitly to a set of addresses using the
    #    "bind" directive.
    # 2) No password is configured.
    #
    # The server only accepts connections from clients connecting from the
    # IPv4 and IPv6 loopback addresses 127.0.0.1 and ::1, and from Unix domain
    # sockets.
    #
    # By default protected mode is enabled. You should disable it only if
    # you are sure you want clients from other hosts to connect to Redis
    # even if no authentication is configured, nor a specific set of interfaces
    # are explicitly listed using the "bind" directive.

说明

  • 用一段代码就可以说明什么是protected-mode

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    if (protected-mode && !requirepass && !bind) {
    	Allow only 127.0.0.1,::1 or socket connections
        Deny (with the long message ever!) others 
    }

  • 其实设置成默认是为了保护对redis不了解的人，提供安全性，但是对于对于不需要bind和requirepass的使用者（例如内网），需要将protected-mode设置为no

  • (2).supervised(默认是no)
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    # If you run Redis from upstart or systemd, Redis can interact with your
    # supervision tree. Options:
    #   supervised no      - no supervision interaction
    #   supervised upstart - signal upstart by putting Redis into SIGSTOP mode
    #   supervised systemd - signal systemd by writing READY=1 to $NOTIFY_SOCKET
    #   supervised auto    - detect upstart or systemd method based on
    #                        UPSTART_JOB or NOTIFY_SOCKET environment variables
    # Note: these supervision methods only signal "process is ready."
    #       They do not enable continuous liveness pings back to your supervisor.

说明
可以通过upstart和systemd管理Redis守护进程，这个参数是和具体的操作系统相关的。

  • (3).bind (Redis3.2.0中bind默认是127.0.0.1)
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    # By default, if no "bind" configuration directive is specified, Redis listens
    # for connections from all the network interfaces available on the server.
    # It is possible to listen to just one or multiple selected interfaces using
    # the "bind" configuration directive, followed by one or more IP addresses.
    #
    # Examples:
    #
    # bind 192.168.1.100 10.0.0.1
    # bind 127.0.0.1 ::1
    #
    # ~~~ WARNING ~~~ If the computer running Redis is directly exposed to the
    # internet, binding to all the interfaces is dangerous and will expose the
    # instance to everybody on the internet. So by default we uncomment the
    # following bind directive, that will force Redis to listen only into
    # the IPv4 lookback interface address (this means Redis will be able to
    # accept connections only from clients running into the same computer it
    # is running).
    #
    # IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES
    # JUST COMMENT THE FOLLOWING LINE.
    # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    bind 127.0.0.1

说明
bind在Redis3.2.0之前默认是0.0.0.0或者说””，为了保证不太了解Redis安全性的人，在Redis3.2.0中bind默认是127.0.0.1,也就是只有本机回环地址可以访问。如果需要配置sentinel、cluster或者需要机器机器可以访问该Redis实例请修改为0.0.0.0或者指定的内网IP.

  • (4).list-max-ziplist-size(默认-2)

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    # Lists are also encoded in a special way to save a lot of space.
    # The number of entries allowed per internal list node can be specified
    # as a fixed maximum size or a maximum number of elements.
    # For a fixed maximum size, use -5 through -1, meaning:
    # -5: max size: 64 Kb  <-- not recommended for normal workloads
    # -4: max size: 32 Kb  <-- not recommended
    # -3: max size: 16 Kb  <-- probably not recommended
    # -2: max size: 8 Kb   <-- good
    # -1: max size: 4 Kb   <-- good
    # Positive numbers mean store up to _exactly_ that number of elements
    # per list node.
    # The highest performing option is usually -2 (8 Kb size) or -1 (4 Kb size),
    # but if your use case is unique, adjust the settings as necessary.

  • (5).list-compress-depth(默认是0)

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    # Lists may also be compressed.
    # Compress depth is the number of quicklist ziplist nodes from *each* side of
    # the list to *exclude* from compression.  The head and tail of the list
    # are always uncompressed for fast push/pop operations.  Settings are:
    # 0: disable all list compression
    # 1: depth 1 means "don't start compressing until after 1 node into the list,
    #    going from either the head or tail"
    #    So: [head]->node->node->...->node->[tail]
    #    [head], [tail] will always be uncompressed; inner nodes will compress.
    # 2: [head]->[next]->node->node->...->node->[prev]->[tail]
    #    2 here means: don't compress head or head->next or tail->prev or tail,
    #    but compress all nodes between them.
    # 3: [head]->[next]->[next]->node->node->...->node->[prev]->[prev]->[tail]
    # etc.

说明
Redis3.2.0引入了新的quicklist的数据结构做了list的底层存储方案。废弃了原来的两个配置参数，list-max-ziplist-entries和list-max-ziplist-value

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127.0.0.1:6388> config get list-max-ziplist-size
1) "list-max-ziplist-size"
2) "-2"
127.0.0.1:6388> config get list-compress-depth
1) "list-compress-depth"
2) "0"
127.0.0.1:6388> lpush user_list u1 u2 u5 u7 u99 u10 u3
(integer) 7
127.0.0.1:6388> object encoding user_list
"quicklist"

在Redis3.2.0中设置原来的参数已经不生效了，应该是无法使用了。

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127.0.0.1:6388> config set list-max-ziplist-entries 512
(error) ERR Unsupported CONFIG parameter: list-max-ziplist-entries
127.0.0.1:6388> config set list-max-ziplist-value 64
(error) ERR Unsupported CONFIG parameter: list-max-ziplist-value

有关quicklist的详细使用还需要查询文档和源码来研究

三、 Redis3.0与3.2关于Cluster的一些变化(来自3.2-release-notes)

原文：

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Redis Cluster changes:
All the Redis Cluster changes in 3.2 were backported to 3.0, so there is
technically nothing new for now in this release. The most important things
are:
* Cluster rebalancing.
* A pipelined MIGRATE command which is 10x faster and makes resharding
  and rebalancing faster.
* Improved replicas migration.
* As a side effect of quicklists encoding (see above items), moving big
  lists between nodes is now a lot faster.

Redis3.2.0的cluster完全兼容Redis3.0,也就是说可以混合部署组成集群，在Redis Cluster上Redis3.2.0没有做什么新的技术，但是也有一些比较重要的事情：

  • Redis Cluster均衡（应该是指redis-trib.rb中实现类将slot进行负载均衡的功能）
  • 提供了一个基于流水线的migrate命令，用于水平迁移数据，速度是原来的10倍多。
  • 提升了从几点迁移的功能。
  • 在quicklist这种新的数据结构的帮助下，在节点之间迁移大的big list快了很多.

注意：上述特性均在Redis3.0.7有体现，如果对于Redis3.2.0不太放心的话，可以使用Redis3.0.7。

四、 Redis3.0与3.2关于Sentinel的一些变化(来自3.2-release-notes)

原文：

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Redis Sentinel changes:
* [NEW] Sentinel connection sharing. Makes Sentinels able to scale to
        monitor many masters. (Salvatore Sanfilippo)
* [NEW] New SENTINEL INFO-CACHE command. (Matt Stancliff)
* More things backported to Redis 3.0 in the past, so no longer news of 3.2.

  • Sentinel connection sharing不太了解，看着像是添加新的sentinel节点后，可以共享其他sentinel节点的master，对于sentinel监控多个master比较有用，这样扩展sentinel节点时候比较方便配置，有关这个后面会继续试验。
  • 提供info-cache命令

有关Sentinel，3.2.0完全向后兼容3.0

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