Redis系统介绍

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Redis系统介绍

参考&＃xff1a;http://blog.nosqlfan.com/html/3139.html?ref&＃61;rediszt

Redis系统性介绍

作者&＃xff1a;nosqlfan on 星期天, 九月 25, 2011 · 2条评论【阅读&＃xff1a;45,010 次】

虽然Redis已经很火了&＃xff0c;相信还是有很多同学对Redis只是有所听闻或者了解并不全面&＃xff0c;下面是一个比较系统的Redis介绍&＃xff0c;对Redis的特性及各种数据类型及操作进行了介绍。是一个很不错的Redis入门教程。

1.介绍

1.1 Redis是什么

REmote DIctionary Server(Redis) 是一个由Salvatore Sanfilippo写的key-value存储系统。Redis提供了一些丰富的数据结构&＃xff0c;包括 lists, sets, ordered sets 以及 hashes &＃xff0c;当然还有和Memcached一样的 strings结构.Redis当然还包括了对这些数据结构的丰富操作。

1.2 Redis的优点

性能极高 – Redis能支持超过 100K&＃43; 每秒的读写频率。
丰富的数据类型 – Redis支持二进制案例的 Strings, Lists, Hashes, Sets 及 Ordered Sets 数据类型操作。
原子 – Redis的所有操作都是原子性的&＃xff0c;同时Redis还支持对几个操作全并后的原子性执行。
丰富的特性 – Redis还支持 publish/subscribe, 通知, key 过期等等特性。

2.数据类型

2.1 String类型

Redis能存储二进制安全的字符串&＃xff0c;最大长度为1GB

redis 127.0.0.1:6379> SET name "John Doe" OK redis 127.0.0.1:6379> GET name "John Doe"

String类型还支持批量的读写操作

redis 127.0.0.1:6379> MSET age 30 sex "male" OK redis 127.0.0.1:6379> MGET age sex 1) "30" 2) "male"

String类型其实也可以用来存储数字&＃xff0c;并支持对数字的加减操作。

redis 127.0.0.1:6379> INCR age (integer) 31 redis 127.0.0.1:6379> INCRBY age 4 (integer) 35 redis 127.0.0.1:6379> GET age "35" redis 127.0.0.1:6379> DECR age (integer) 34 redis 127.0.0.1:6379> DECRBY age 4 (integer) 30 redis 127.0.0.1:6379> GET age "30"

String类型还支持对其部分的修改和获取操作

redis 127.0.0.1:6379> APPEND name " Mr." (integer) 12 redis 127.0.0.1:6379> GET name "John Doe Mr." redis 127.0.0.1:6379> STRLEN name (integer) 12 redis 127.0.0.1:6379> SUBSTR name 0 3 "John"

2.2 List类型

Redis能够将数据存储成一个链表&＃xff0c;并能对这个链表进行丰富的操作

redis 127.0.0.1:6379> LPUSH students "John Doe" (integer) 1 redis 127.0.0.1:6379> LPUSH students "Captain Kirk" (integer) 2 redis 127.0.0.1:6379> LPUSH students "Sheldon Cooper" (integer) 3 redis 127.0.0.1:6379> LLEN students (integer) 3 redis 127.0.0.1:6379> LRANGE students 0 2 1) "Sheldon Cooper" 2) "Captain Kirk" 3) "John Doe" redis 127.0.0.1:6379> LPOP students "Sheldon Cooper" redis 127.0.0.1:6379> LLEN students (integer) 2 redis 127.0.0.1:6379> LRANGE students 0 1 1) "Captain Kirk" 2) "John Doe" redis 127.0.0.1:6379> LREM students 1 "John Doe" (integer) 1 redis 127.0.0.1:6379> LLEN students (integer) 1 redis 127.0.0.1:6379> LRANGE students 0 0 1) "Captain Kirk"

Redis也支持很多修改操作

redis 127.0.0.1:6379> LINSERT students BEFORE "Captain Kirk" "Dexter Morgan" (integer) 3 redis 127.0.0.1:6379> LRANGE students 0 2 1) "Dexter Morgan" 2) "Captain Kirk" 3) "John Doe" redis 127.0.0.1:6379> LPUSH students "Peter Parker" (integer) 4 redis 127.0.0.1:6379> LRANGE students 0 3 1) "Peter Parker" 2) "Dexter Morgan" 3) "Captain Kirk" 4) "John Doe" redis 127.0.0.1:6379> LTRIM students 1 3 OK redis 127.0.0.1:6379> LLEN students (integer) 3 redis 127.0.0.1:6379> LRANGE students 0 2 1) "Dexter Morgan" 2) "Captain Kirk" 3) "John Doe" redis 127.0.0.1:6379> LREM students 1 "John Doe" (integer) 1 redis 127.0.0.1:6379> LLEN students (integer) 1 redis 127.0.0.1:6379> LRANGE students 0 1 1) "Captain Kirk"

2.3 集合&＃xff08;Sets&＃xff09;类型

Redis能够将一系列不重复的值存储成一个集合

redis 127.0.0.1:6379> SADD birds crow (integer) 1 redis 127.0.0.1:6379> SADD birds pigeon (integer) 1 redis 127.0.0.1:6379> SADD birds bat (integer) 1 redis 127.0.0.1:6379> SADD mammals dog (integer) 1 redis 127.0.0.1:6379> SADD mammals cat (integer) 1 redis 127.0.0.1:6379> SADD mammals bat (integer) 1 redis 127.0.0.1:6379> SMEMBERS birds 1) "bat" 2) "crow" 3) "pigeon" redis 127.0.0.1:6379> SMEMBERS mammals 1) "bat" 2) "cat" 3) "dog"

Sets结构也支持相应的修改操作

redis 127.0.0.1:6379> SREM mammals cat (integer) 1 redis 127.0.0.1:6379> SMEMBERS mammals 1) "bat" 2) "dog" redis 127.0.0.1:6379> SADD mammals human (integer) 1 redis 127.0.0.1:6379> SMEMBERS mammals 1) "bat" 2) "human" 3) "dog"

Redis还支持对集合的子交并补等操作

redis 127.0.0.1:6379> SINTER birds mammals 1) "bat" redis 127.0.0.1:6379> SUNION birds mammals 1) "crow" 2) "bat" 3) "human" 4) "pigeon" 5) "dog" redis 127.0.0.1:6379> SDIFF birds mammals 1) "crow" 2) "pigeon"

2.4 有序集合&＃xff08;Sorted Sets&＃xff09;类型

Sorted Sets和Sets结构相似&＃xff0c;不同的是存在Sorted Sets中的数据会有一个score属性&＃xff0c;并会在写入时就按这个score排好序。

redis 127.0.0.1:6379> ZADD days 0 mon (integer) 1 redis 127.0.0.1:6379> ZADD days 1 tue (integer) 1 redis 127.0.0.1:6379> ZADD days 2 wed (integer) 1 redis 127.0.0.1:6379> ZADD days 3 thu (integer) 1 redis 127.0.0.1:6379> ZADD days 4 fri (integer) 1 redis 127.0.0.1:6379> ZADD days 5 sat (integer) 1 redis 127.0.0.1:6379> ZADD days 6 sun (integer) 1 redis 127.0.0.1:6379> ZCARD days (integer) 7 redis 127.0.0.1:6379> ZRANGE days 0 6 1) "mon" 2) "tue" 3) "wed" 4) "thu" 5) "fri" 6) "sat" 7) "sun" redis 127.0.0.1:6379> ZSCORE days sat "5" redis 127.0.0.1:6379> ZCOUNT days 3 6 (integer) 4 redis 127.0.0.1:6379> ZRANGEBYSCORE days 3 6 1) "thu" 2) "fri" 3) "sat" 4) "sun"

2.5 Hash类型

Redis能够存储key对多个属性的数据&＃xff08;比如user1.uname user1.passwd&＃xff09;

redis 127.0.0.1:6379> HKEYS student 1) "name" 2) "age" 3) "sex" redis 127.0.0.1:6379> HVALS student 1) "Ganesh" 2) "30" 3) "Male" redis 127.0.0.1:6379> HGETALL student 1) "name" 2) "Ganesh" 3) "age" 4) "30" 5) "sex" 6) "Male" redis 127.0.0.1:6379> HDEL student sex (integer) 1 redis 127.0.0.1:6379> HGETALL student 1) "name" 2) "Ganesh" 3) "age" 4) "30"

Hash数据结构能够批量修改和获取

redis 127.0.0.1:6379> HMSET kid name Akshi age 2 sex Female OK redis 127.0.0.1:6379> HMGET kid name age sex 1) "Akshi" 2) "2" 3) "Female"

3.Publish/Subscribe

Redis支持这样一种特性&＃xff0c;你可以将数据推到某个信息管道中&＃xff0c;然后其它人可以通过订阅这些管道来获取推送过来的信息。

3.1 订阅信息管道

用一个客户端订阅管道

redis 127.0.0.1:6379> SUBSCRIBE channelone Reading messages... (press Ctrl-C to quit) 1) "subscribe" 2) "channelone" 3) (integer) 1

另一个客户端往这个管道推送信息

redis 127.0.0.1:6379> PUBLISH channelone hello (integer) 1 redis 127.0.0.1:6379> PUBLISH channelone world (integer) 1

然后第一个客户端就能获取到推送的信息

redis 127.0.0.1:6379> SUBSCRIBE channelone Reading messages... (press Ctrl-C to quit) 1) "subscribe" 2) "channelone" 3) (integer) 1 1) "message" 2) "channelone" 3) "hello" 1) "message" 2) "channelone" 3) "world"

3.2 按一定模式批量订阅

用下面的命令订阅所有channel开头的信息通道

redis 127.0.0.1:6379> PSUBSCRIBE channel* Reading messages... (press Ctrl-C to quit) 1) "psubscribe" 2) "channel*" 3) (integer) 1

在另一个客户端对两个推送信息

redis 127.0.0.1:6379> PUBLISH channelone hello (integer) 1 redis 127.0.0.1:6379> PUBLISH channeltwo world (integer) 1

然后在第一个客户端就能收到推送的信息

redis 127.0.0.1:6379> PSUBSCRIBE channel* Reading messages... (press Ctrl-C to quit) 1) "psubscribe" 2) "channel*" 3) (integer) 1 1) "pmessage" 2) "channel*" 3) "channelone" 4) "hello" 1) "pmessage" 2) "channel*" 3) "channeltwo" 4) "world"

4.数据过期设置

Redis支持按key设置过期时间&＃xff0c;过期后值将被删除&＃xff08;在客户端看来是补删除了的&＃xff09;

用TTL命令可以获取某个key值的过期时间&＃xff08;-1表示永不过期&＃xff09;

redis 127.0.0.1:6379> SET name "John Doe" OK redis 127.0.0.1:6379> TTL name (integer) -1

下面命令先用EXISTS命令查看key值是否存在&＃xff0c;然后设置了5秒的过期时间

redis 127.0.0.1:6379> SET name "John Doe" OK redis 127.0.0.1:6379> EXISTS name (integer) 1 redis 127.0.0.1:6379> EXPIRE name 5 (integer) 1

5秒后再查看

redis 127.0.0.1:6379> EXISTS name (integer) 0 redis 127.0.0.1:6379> GET name (nil)

这个值已经没有了。

上在是直接设置多少秒后过期&＃xff0c;你也可以设置在某个时间点过期&＃xff0c;下面例子是设置2011-09-24 00:40:00过期。

redis 127.0.0.1:6379> SET name "John Doe" OK redis 127.0.0.1:6379> EXPIREAT name 1316805000 (integer) 1 redis 127.0.0.1:6379> EXISTS name (integer) 0

5.事务性

Redis本身支持一些简单的组合型的命令&＃xff0c;比如以NX结尾命令都是判断在这个值没有时才进行某个命令。

redis 127.0.0.1:6379> SET name "John Doe" OK redis 127.0.0.1:6379> SETNX name "Dexter Morgan" (integer) 0 redis 127.0.0.1:6379> GET name "John Doe"

redis 127.0.0.1:6379> GETSET name "Dexter Morgan" "John Doe" redis 127.0.0.1:6379> GET name "Dexter Morgan"

当然&＃xff0c;Redis还支持自定义的命令组合&＃xff0c;通过MULTI和EXEC&＃xff0c;将几个命令组合起来执行

redis 127.0.0.1:6379> SET counter 0 OK redis 127.0.0.1:6379> MULTI OK redis 127.0.0.1:6379> INCR counter QUEUED redis 127.0.0.1:6379> INCR counter QUEUED redis 127.0.0.1:6379> INCR counter QUEUED redis 127.0.0.1:6379> EXEC 1) (integer) 1 2) (integer) 2 3) (integer) 3 redis 127.0.0.1:6379> GET counter "3"

你还可以用DICARD命令来中断执行中的命令序列

redis 127.0.0.1:6379> SET newcounter 0 OK redis 127.0.0.1:6379> MULTI OK redis 127.0.0.1:6379> INCR newcounter QUEUED redis 127.0.0.1:6379> INCR newcounter QUEUED redis 127.0.0.1:6379> INCR newcounter QUEUED redis 127.0.0.1:6379> DISCARD OK redis 127.0.0.1:6379> GET newcounter "0"

6.持久化

Redis的所有数据都存储在内存中&＃xff0c;但是他也提供对这些数据的持久化。

6.1 数据快照

数据快照的原理是将整个Redis中存的所有数据遍历一遍存到一个扩展名为rdb的数据文件中。通过SAVE命令可以调用这个过程。

redis 127.0.0.1:6379> SET name "John Doe" OK redis 127.0.0.1:6379> SAVE OK redis 127.0.0.1:6379> SET name "Sheldon Cooper" OK redis 127.0.0.1:6379> BGSAVE Background saving started

如果你是使用的brew在Mac OSX上安全的Redis&＃xff0c;那么rdb文件会存在如下路径

/usr/local/var/db/redis/dump.rdb

6.2 Append-Only File&＃xff08;追加式的操作日志记录&＃xff09;

Redis还支持一种追加式的操作日志记录&＃xff0c;叫append only file&＃xff0c;其日志文件以aof结局&＃xff0c;我们一般各为aof文件。要开启aof日志的记录&＃xff0c;你需要在配置文件中进行如下设置&＃xff1a;

appendonly yes

这时候你所有的操作都会记录在aof日志文件中

redis 127.0.0.1:6379> GET name (nil) redis 127.0.0.1:6379> SET name "Ganesh Gunasegaran" OK redis 127.0.0.1:6379> EXIT→ cat /usr/local/var/db/redis/appendonly.aof *2 $6 SELECT $1 0 *3 $3 SET $4 name $18 Ganesh Gunasegaran

7.管理命令

Redis支持多个DB&＃xff0c;默认是16个&＃xff0c;你可以设置将数据存在哪一个DB中&＃xff0c;不同DB间的数据具有隔离性。也可以在多个DB间移动数据。

redis 127.0.0.1:6379> SELECT 0 OK redis 127.0.0.1:6379> SET name "John Doe" OK redis 127.0.0.1:6379> SELECT 1 OK redis 127.0.0.1:6379[1]> GET name (nil) redis 127.0.0.1:6379[1]> SELECT 0 OK redis 127.0.0.1:6379> MOVE name 1 (integer) 1 redis 127.0.0.1:6379> SELECT 1 OK redis 127.0.0.1:6379[1]> GET name "John Doe"

Redis还能进行一些如下操作&＃xff0c;获取一些运行信息

redis 127.0.0.1:6379[1]> DBSIZE (integer) 1 redis 127.0.0.1:6379[1]> INFO redis_version:2.2.13 redis_git_sha1:00000000 redis_git_dirty:0 arch_bits:64 multiplexing_api:kqueue ......

Redis还支持对某个DB数据进行清除&＃xff08;当然清空所有数据的操作也是支持的&＃xff09;

redis 127.0.0.1:6379> SET name "John Doe" OK redis 127.0.0.1:6379> DBSIZE (integer) 1 redis 127.0.0.1:6379> SELECT 1 OK redis 127.0.0.1:6379[1]> SET name "Sheldon Cooper" OK redis 127.0.0.1:6379[1]> DBSIZE (integer) 1 redis 127.0.0.1:6379[1]> SELECT 0 OK redis 127.0.0.1:6379> FLUSHDB OK redis 127.0.0.1:6379> DBSIZE (integer) 0 redis 127.0.0.1:6379> SELECT 1 OK redis 127.0.0.1:6379[1]> DBSIZE (integer) 1 redis 127.0.0.1:6379[1]> FLUSHALL OK redis 127.0.0.1:6379[1]> DBSIZE (integer) 0