Redis 知识整理
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前言：
Redis 介绍：轻量级、Key-Value、内存数据库、支持持久化
Redis 数据结构：string（字符串），hash（哈希），list（列表），set（集合）及 zset (sorted set：有序集合)
Redis 应用场景：访问频繁的数据（缓存）；及时性要求不高的且频繁功能数据；
不变的明细数据且需要频繁运算的；及队列数据（非官方个人经验）
Redis 可视化工具：RedisDesktopManager 安装文件传送门
总结：Redis 不像关系型数据库，可以自定义库名、用户、权限等，
客户端要么可以访问全部数据库，要么一个数据库权限都没有；
一、安装
轻量级安装文件才几MB，都是程序员差距如此之大；
二、数据结构
主要介绍常用的几种： string 传送门 、hash 传送门 、list 传送门 （博主写的很详细）
简单描述一下差异以及应用场景：
通俗易懂的讲：
string 就是 Key/Value 键名对应一个数据值，
hash 就是 Key/Entity 键名对应一个集合（实体对象），
list 就是 Key/List 键名对应一个字符串列表（可动态增加及排序）
set 就是键名对应一个 string 类型的无序集合，通过 hash 实现操作删除、修改性能差；
string：Redis 的基本数据类型，二进制安全的，Value 最大值 512 MB；
语法：SET [name] [value]、 GET [name] [value]
"函数"：Append、GetSet、StrLen 等...
一般应用于存储某一个字段的数据，如果用户登录的 Cookie 信息，以及图片、音频文件等；
hash：是一个 string 类型的 field 和 value 的映射表，hash 特别适合用于存储对象。
语法：HSET [name] [value]、HGET [name] [value]
HMGET [name] [value] [value]
list：链表数据结构，头尾数据获取快，同时灵活性很强；具有阻塞等高级特性；
语法：lPush [name] [value]、lRange [name] [StartIndex] [Count]
"函数"/高级特性：bLpop, bRpop, bRpoplPush
一般应用于存储列表多数据，排序等需求，看如上介绍来定；
三、参考代码（工具代码）
根据自己的开发语言自行选择；Redis 官方已列出了主流的几个对 Redis 封装的主键；
锚点语言标记以后应该是有不同的封装，根据自己的需求来选择性下载；
// 选择 C# --> StackExchange.Redis --> Download
// 也可以在 Nuget Download
四、配置文件详解
文件名介绍：
redis-server Redis 服务器
redis-cli Redis 客户端
Redis-benchmark Redis 性能测试工具
Redis-check-aof Redis AOF 文件修复工具
Redis-check-dump Redis RDB 文件检查工具
【基础配置】 redis.conf daemonize no // 后台运行 port 6379 // 端口 tcp-backlog 511 // TCP 监听的最大容纳数量 (并发量大的情况下建议设置高一些) timeout 0 // 空闲多少秒后销毁连接 ( 0 永不关闭) tcp-keepalive 0 // tcp 是否长连接 ( 0 禁用) [根据业务需求来设定，很重要] loglevel notice // 日志级别 (notice 生产环境) [其他几个选项顾名思义] databases 16 // 数据库个数，默认 16 【快照配置】 save 900 1 // 快照保存磁盘设置；(根据给定的时间间隔和写入次数将数据保存到磁盘) 参数：save [second] [key 至少发送变化次数] stop-writes-on-bgsave-error yes // 后台保存失败停止写入 rdbcompression yes // dump.rdb 快照文件是否启用压缩 rdbchecksum yes // 是否校验 rdb 持久化文件 Redis 持久化的两种模式 【主从配置】 slave-serve-stale-data yes // 主从复制 slave-read-only yes // 是否只读 slave-priority 100 // 主库出问题从库选择优先级 【安全配置】 requirepass foobared // 设置认证密码 【限制配置】 maxclients 10000 // 客户端最大连接数 maxmemory <bytes> // 最大使用内存 maxmemory-policy noeviction // 内存存储策略 （高级配置） 【持久化配置】 appendonly no // 是否追加到 .aof 文件的末尾 (Redis 重启后可以重建数据集) appendfsync everysec // 持久化机制配置 no-appendfsync-on-rewrite no // 持久化是否写入缓冲区配合 （no 为不写入缓冲区，断点不会丢失数据，性能差一点） 【Lua 配置】 lua-time-limit 5000 // Lua 脚本最大执行时间 【集群配置】 cluster-enabled yes // 是否启用集群 cluster-config-file nodes-6379.conf // 集群节点配置文件 【事件通知配置】 // 哈哈，好像是我自己想多了。 【高级配置】 // 配置字符编码、最大数目等信息； hz 10 // 执行后台任务频率间隔时间 (不要轻易修改)
附上配置文件，有英文阅读能力的可以看看，但是核心的都过了一遍。
# Redis configuration file example # Note on units: when memory size is needed, it is possible to specify # it in the usual form of 1k 5GB 4M and so forth: # # 1k => 1000 bytes # 1kb => 1024 bytes # 1m => 1000000 bytes # 1mb => 1024*1024 bytes # 1g => 1000000000 bytes # 1gb => 1024*1024*1024 bytes # # units are case insensitive so 1GB 1Gb 1gB are all the same. ################################## INCLUDES ################################### # Include one or more other config files here. This is useful if you # have a standard template that goes to all Redis servers but also need # to customize a few per-server settings. Include files can include # other files, so use this wisely. # # Notice option "include" won\'t be rewritten by command "CONFIG REWRITE" # from admin or Redis Sentinel. Since Redis always uses the last processed # line as value of a configuration directive, you\'d better put includes # at the beginning of this file to avoid overwriting config change at runtime. # # If instead you are interested in using includes to override configuration # options, it is better to use include as the last line. # # include .\\path\\to\\local.conf # include c:\\path\\to\\other.conf ################################ GENERAL ##################################### # On Windows, daemonize and pidfile are not supported. # However, you can run redis as a Windows service, and specify a logfile. # The logfile will contain the pid. # Accept connections on the specified port, default is 6379. # If port 0 is specified Redis will not listen on a TCP socket. port 6379 # TCP listen() backlog. # # In high requests-per-second environments you need an high backlog in order # to avoid slow clients connections issues. Note that the Linux kernel # will silently truncate it to the value of /proc/sys/net/core/somaxconn so # make sure to raise both the value of somaxconn and tcp_max_syn_backlog # in order to get the desired effect. tcp-backlog 511 # By default Redis listens for connections from all the network interfaces # available on the server. It is possible to listen to just one or multiple # 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 # Specify the path for the Unix socket that will be used to listen for # incoming connections. There is no default, so Redis will not listen # on a unix socket when not specified. # # unixsocket /tmp/redis.sock # unixsocketperm 700 # Close the connection after a client is idle for N seconds (0 to disable) timeout 0 # TCP keepalive. # # If non-zero, use SO_KEEPALIVE to send TCP ACKs to clients in absence # of communication. This is useful for two reasons: # # 1) Detect dead peers. # 2) Take the connection alive from the point of view of network # equipment in the middle. # # On Linux, the specified value (in seconds) is the period used to send ACKs. # Note that to close the connection the double of the time is needed. # On other kernels the period depends on the kernel configuration. # # A reasonable value for this option is 60 seconds. tcp-keepalive 0 # Specify the server verbosity level. # This can be one of: # debug (a lot of information, useful for development/testing) # verbose (many rarely useful info, but not a mess like the debug level) # notice (moderately verbose, what you want in production probably) # warning (only very important / critical messages are logged) loglevel notice # Specify the log file name. Also \'stdout\' can be used to force # Redis to log on the standard output. logfile "Logs/redis_log.txt" # To enable logging to the Windows EventLog, just set \'syslog-enabled\' to # yes, and optionally update the other syslog parameters to suit your needs. # If Redis is installed and launched as a Windows Service, this will # automatically be enabled. syslog-enabled yes # Specify the source name of the events in the Windows Application log. syslog-ident redis # Set the number of databases. The default database is DB 0, you can select # a different one on a per-connection basis using SELECT <dbid> where # dbid is a number between 0 and \'databases\'-1 databases 16 ################################ SNAPSHOTTING ################################ # # Save the DB on disk: # # save <seconds> <changes> # # Will save the DB if both the given number of seconds and the given # number of write operations against the DB occurred. # # In the example below the behaviour will be to save: # after 900 sec (15 min) if at least 1 key changed # after 300 sec (5 min) if at least 10 keys changed # after 60 sec if at least 10000 keys changed # # Note: you can disable saving completely by commenting out all "save" lines. # # It is also possible to remove all the previously configured save # points by adding a save directive with a single empty string argument # like in the following example: # # save "" save 900 1 save 300 10 save 60 10000 # By default Redis will stop accepting writes if RDB snapshots are enabled # (at least one save point) and the latest background save failed. # This will make the user aware (in a hard way) that data is not persisting # on disk properly, otherwise chances are that no one will notice and some # disaster will happen. # # If the background saving process will start working again Redis will # automatically allow writes again. # # However if you have setup your proper monitoring of the Redis server # and persistence, you may want to disable this feature so that Redis will # continue to work as usual even if there are problems with disk, # permissions, and so forth. stop-writes-on-bgsave-error yes # Compress string objects using LZF when dump .rdb databases? # For default that\'s set to \'yes\' as it\'s almost always a win. # If you want to save some CPU in the saving child set it to \'no\' but # the dataset will likely be bigger if you have compressible values or keys. rdbcompression yes # Since version 5 of RDB a CRC64 checksum is placed at the end of the file. # This makes the format more resistant to corruption but there is a performance # hit to pay (around 10%) when saving and loading RDB files, so you can disable it # for maximum performances. # # RDB files created with checksum disabled have a checksum of zero that will # tell the loading code to skip the check. rdbchecksum yes # The filename where to dump the DB dbfilename dump.rdb # The working directory. # # The DB will be written inside this directory, with the filename specified # above using the \'dbfilename\' configuration directive. # # The Append Only File will also be created inside this directory. # # Note that you must specify a directory here, not a file name. dir ./ ################################# REPLICATION ################################# # Master-Slave replication. Use slaveof to make a Redis instance a copy of # another Redis server. A few things to understand ASAP about Redis replication. # # 1) Redis replication is asynchronous, but you can configure a master to # stop accepting writes if it appears to be not connected with at least # a given number of slaves. # 2) Redis slaves are able to perform a partial resynchronization with the # master if the replication link is lost for a relatively small amount of # time. You may want to configure the replication backlog size (see the next # sections of this file) with a sensible value depending on your needs. # 3) Replication is automatic and does not need user intervention. After a # network partition slaves automatically try to reconnect to masters # and resynchronize with them. # # slaveof <masterip> <masterport> # If the master is password protected (using the "requirepass" configuration # directive below) it is possible to tell the slave to authenticate before # starting the replication synchronization process, otherwise the master will # refuse the slave request. # # masterauth <master-password> # When a slave loses its connection with the master, or when the replication # is still in progress, the slave can act in two different ways: # # 1) if slave-serve-stale-data is set to \'yes\' (the default) the slave will # still reply to client requests, possibly with out of date data, or the # data set may just be empty if this is the first synchronization. # # 2) if slave-serve-stale-data is set to \'no\' the slave will reply with # an error "SYNC with master in progress" to all the kind of commands # but to INFO and SLAVEOF. # slave-serve-stale-data yes # You can configure a slave instance to accept writes or not. Writing against # a slave instance may be useful to store some ephemeral data (because data # written on a slave will be easily deleted after resync with the master) but # may also cause problems if clients are writing to it because of a # misconfiguration. # # Since Redis 2.6 by default slaves are read-only. # # Note: read only slaves are not designed to be exposed to untrusted clients # on the internet. It\'s just a protection layer against misuse of the instance. # Still a read only slave exports by default all the administrative commands # such as CONFIG, DEBUG, and so forth. To a limited extent you can improve # security of read only slaves using \'rename-command\' to shadow all the # administrative / dangerous commands. slave-read-only yes # Replication SYNC strategy: disk or socket. # # ------------------------------------------------------- # WARNING: DISKLESS REPLICATION IS EXPERIMENTAL CURRENTLY # ------------------------------------------------------- # # New slaves and reconnecting slaves that are not able to continue the replication # process just receiving differences, need to do what is called a "full # synchronization". An RDB file is transmitted from the master to the slaves. # The transmission can happen in two different ways: # # 1) Disk-backed: The Redis master creates a new process that writes the RDB # file on disk. Later the file is transferred by the parent # process to the slaves incrementally. # 2) Diskless: The Redis master creates a new process that directly writes the # RDB file to slave sockets, without touching the disk at all. # # With disk-backed replication, while the RDB file is generated, more slaves # can be queued and served with the RDB file as soon as the current child producing # the RDB file finishes its work. With diskless replication instead once # the transfer starts, new slaves arriving will be queued and a new transfer # will start when the current one terminates. # # When diskless replication is used, the master waits a configurable amount of # time (in seconds) before starting the transfer in the hope that multiple slaves # will arrive and the transfer can be parallelized. # # With slow disks and fast (large bandwidth) networks, diskless replication # works better. repl-diskless-sync no # When diskless replication is enabled, it is possible to configure the delay # the server waits in order to spawn the child that transfers the RDB via socket # to the slaves. # # This is important since once the transfer starts, it is not possible to serve # new slaves arriving, that will be queued for the next RDB transfer, so the server # waits a delay in order to let more slaves arrive. # # The delay is specified in seconds, and by default is 5 seconds. To disable # it entirely just set it to 0 seconds and the transfer will start ASAP. repl-diskless-sync-delay 5 # Slaves send PINGs to server in a predefined interval. It\'s possible to change # this interval with the repl_ping_slave_period option. The default value is 10 # seconds. # # repl-ping-slave-period 10 # The following option sets the replication timeout for: # # 1) Bulk transfer I/O during SYNC, from the point of view of slave. # 2) Master timeout from the point of view of slaves (data, pings). # 3) Slave timeout from the point of view of masters (REPLCONF ACK pings). # # It is important to make sure that this value is greater than the value # specified for repl-ping-slave-period otherwise a timeout will be detected # every time there is low traffic between the master and the slave. # # repl-timeout 60 # Disable TCP_NODELAY on the slave socket after SYNC? # # If you select "yes" Redis will use a smaller number of TCP packets and # less bandwidth to send data to slaves. But this can add a delay for # the data to appear on the slave side, up to 40 milliseconds with # Linux kernels using a default configuration. # # If you select "no" the delay for data to appear on the slave side will # be reduced but more bandwidth will be used for replication. # # By default we optimize for low latency, but in very high traffic conditions # or when the master and slaves are many hops away, turning this to "yes" may # be a good idea. repl-disable-tcp-nodelay no # Set the replication backlog size. The backlog is a buffer that accumulates # slave data when slaves are disconnected for some time, so that when a slave # wants to reconnect again, often a full resync is not needed, but a partial # resync is enough, just passing the portion of data the slave missed while # disconnected. # # The bigger the replication backlog, the longer the time the slave can be # disconnected and later be able to perform a partial resynchronization. # # The backlog is only allocated once there is at least a slave connected. # # repl-backlog-size 1mb # After a master has no longer connected slaves for some time, the backlog # will be freed. The following option configures the amount of seconds that # need to elapse, starting from the time the last slave disconnected, for # the backlog buffer to be freed. # # A value of 0 means to never release the backlog. # # repl-backlog-ttl 3600 # The slave priority is an integer number published by Redis in the INFO output. # It is used by Redis Sentinel in order to select a slave to promote into a # master if the master is no longer working correctly. # # A slave with a low priority number is considered better for promotion, so # for instance if there are three slaves with priority 10, 100, 25 Sentinel will # pick the one with priority 10, that is the lowest. # # However a special priority of 0 marks the slave as not able to perform the # role of master, so a slave with priority of 0 will never be selected by # Redis Sentinel for promotion. # # By default the priority is 100. slave-priority 100 # It is possible for a master to stop accepting writes if there are less than # N slaves connected, having a lag less or equal than M seconds. # # The N slaves need to be in "online" state. # # The lag in seconds, that must be <= the specified value, is calculated from # the last ping received from the slave, that is usually sent every second. # # This option does not GUARANTEE that N replicas will accept the write, but # will limit the window of exposure for lost writes in case not enough slaves # are available, to the specified number of seconds. # # For example to require at least 3 slaves with a lag <= 10 seconds use: # # min-slaves-to-write 3 # min-slaves-max-lag 10 # # Setting one or the other to 0 disables the feature. # # By default min-slaves-to-write is set to 0 (feature disabled) and # min-slaves-max-lag is set to 10. ################################## SECURITY ################################### # Require clients to issue AUTH <PASSWORD> before processing any other # commands. This might be useful in environments in which you do not trust # others with access to the host running redis-server. # # This should stay commented out for backward compatibility and because most # people do not need auth (e.g. they run their own servers). # # Warning: since Redis is pretty fast an outside user can try up to # 150k passwords per second against a good box. This means that you should # use a very strong password otherwise it will be very easy to break. # # requirepass foobared # Command renaming. # # It is possible to change the name of dangerous commands in a shared # environment. For instance the CONFIG command may be renamed into something # hard to guess so that it will still be available for internal-use tools # but not available for general clients. # # Example: # # rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52 # # It is also possible to completely kill a command by renaming it into # an empty string: # # rename-command CONFIG "" # # Please note that changing the name of commands that are logged into the # AOF file or transmitted to slaves may cause problems. ################################### LIMITS #################################### # Set the max number of connected clients at the same time. By default # this limit is set to 10000 clients, however if the Redis server is not # able to configure the process file limit to allow for the specified limit # the max number of allowed clients is set to the current file limit # minus 32 (as Redis reserves a few file descriptors for internal uses). # # Once the limit is reached Redis will close all the new connections sending # an error \'max number of clients reached\'. # # maxclients 10000 # If Redis is to be used as an in-memory-only cache without any kind of # persistence, then the fork() mechanism used by the background AOF/RDB # persistence is unnecessary. As an optimization, all persistence can be # turned off in the Windows version of Redis. This will redirect heap # allocations to the system heap allocator, and disable commands that would # otherwise cause fork() operations: BGSAVE and BGREWRITEAOF. # This flag may not be combined with any of the other flags that configure # AOF and RDB operations. # persistence-available [(yes)|no] # Don\'t use more memory than the specified amount of bytes. # When the memory limit is reached Redis will try to remove keys # according to the eviction policy selected (see maxmemory-policy). # # If Redis can\'t remove keys according to the policy, or if the policy is # set to \'noeviction\', Redis will start to reply with errors to commands # that would use more memory, like SET, LPUSH, and so on, and will continue # to reply to read-only commands like GET. # # This option is usually useful when using Redis as an LRU cache, or to set # a hard memory limit for an instance (using the \'noeviction\' policy). # # WARNING: If you have slaves attached to an instance with maxmemory on, # the size of the output buffers needed to feed the slaves are subtracted # from the used memory count, so that network problems / resyncs will # not trigger a loop where keys are evicted, and in turn the output # buffer of slaves is full with DELs of keys evicted triggering the deletion # of more keys, and so forth until the database is completely emptied. # # In short... if you have slaves attached it is suggested that you set a lower # limit for maxmemory so that there is some free RAM on the system for slave # output buffers (but this is not needed if the policy is \'noeviction\'). # # WARNING: not setting maxmemory will cause Redis to terminate with an # out-of-memory exception if the heap limit is reached. # # NOTE: since Redis uses the system paging file to allocate the heap memory, # the Working Set memory usage showed by the Windows Task Manager or by other # tools such as ProcessExplorer will not always be accurate. For example, right # after a background save of the RDB or the AOF files, the working set value # may drop significantly. In order to check the correct amount of memory used # by the redis-server to store the data, use the INFO client command. The INFO # command shows only the memory used to store the redis data, not the extra # memory used by the Windows process for its own requirements. Th3 extra amount # of memory not reported by the INFO command can be calculated subtracting the # Peak Working Set reported by the Windows Task Manager and the used_memory_peak # reported by the INFO command. # # maxmemory <bytes> # MAXMEMORY POLICY: how Redis will select what to remove when maxmemory # is reached. You can select among five behaviors: # # volatile-lru -> remove the key with an expire set using an LRU algorithm # allkeys-lru -> remove any key according to the LRU algorithm # volatile-random -> remove a random key with an expire set # allkeys-random -> remove a random key, any key # volatile-ttl -> remove the key with the nearest expire time (minor TTL) # noeviction -> don\'t expire at all, just return an error on write operations # # Note: with any of the above policies, Redis will return an error on write # operations, when there are no suitable keys for eviction. # # At the date of writing these commands are: set setnx setex append # incr decr rpush lpush rpushx lpushx linsert lset rpoplpush sadd # sinter sinterstore sunion sunionstore sdiff sdiffstore zadd zincrby # zunionstore zinterstore hset hsetnx hmset hincrby incrby decrby # getset mset msetnx exec sort # # The default is: # # maxmemory-policy noeviction # LRU and minimal TTL algorithms are not precise algorithms but approximated # algorithms (in order to save memory), so you can select as well the sample # size to check. For instance for default Redis will check three keys and # pick the one that was used less recently, you can change the sample size # using the following configuration directive. # # maxmemory-samples 3 ###########以上是关于Redis 知识整理的主要内容，如果未能解决你的问题，请参考以下文章