• 一文了解：Redis基础类型

    一文了解：Redis基础类型

    Redis特点

    开源的，BSD许可高级的key-value存储系统
    可以用来存储字符串，哈希结构，链表，集合

    安装

    windows：https://github.com/microsoftarchive/redis/releases

    maclinux：http://www.redis.cn/

    Redis 数据类型

    Redis支持五种数据类型：string（字符串），hash（哈希），list（列表），set（集合）及zset（有序集合）。

    string（字符串）

    字符串类型是Redis的最基本数据结构。
    字符串类型的值实际可以为字符串，数字，二进制，但是值最大不能超过512M。

    key value
    hello world
    counter 1
    bits 10000100
    json {"id":1,"name":"xiaocai","age":18}

    string命令

    设置

    set key value [EX seconds] [PX milliseconds] [NX|XX]

    get key

    > set name xiaocai
OK
> get name
"xiaocai"

    过期

    setex key seconds value

    > set name1 redis1 ex 10 #10秒后过期
OK
> get name1
(nil)

> setex name2 10 redis2 #10秒后过期
OK
> get name2
"redis2"
> get name2
(nil)

> set name3 redis3 px 10 #10豪秒后过期
OK
> get name3
(nil)

    不存在才能设置成功或者必须存在才能设置成功

    > set hello world nx #不存在才能设置成功
OK
> set hello w nx #存在就设置失败
(nil)
> get hello
"world"

>set hello w xx  #存在才能设置成功
OK
> set world hello xx #不存在就设置失败
(nil)
> get hello
"w"
> get world
(nil)

    批量设置

    mset key value [key value ...]
mget key [key ...]


> mset name1 redis1 name2 redis2
OK

> mget name1 name2
1) "redis1"
2) "redis2"

> mget name1 name2 name3
1) "redis1"
2) "redis2"
3) (nil)

    计数

    incr key

    incrby key increment

    > set age 18  #value只能为整数
OK
> incr age
(integer) 19
> incrby age -5
(integer) 14
> incrby age 10
(integer) 24

    删除

    del key [key ...]

    > del age
(integer) 1
> get age
(nil)

    内部编码

    1. int 8个字节的长整型
    2. embstr 小于等于39个字节的字符串
    3. raw 大于39个字节的字符串
    > set port 6379
OK
> object encoding port
"int"

> set hello world
OK
> object encoding hello 
"embstr"

> set longString abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz
OK
> object encoding hello
"raw"
> strlen longString
(integer) 52

    list（列表）

    list类型是用来存储多个有序的字符串。每列字符串称之为元素。一个list的最大存储为2^32-1个元素。可以对列表进行双端插入和弹出，也可以指定索引下标获取元素。

    列表

    list命令

    头部和尾部添加元素

    lpush key value [value ...]

    rpush key value [value ...]

    lrange key start stop

    > lpush letter "a"
(integer) 1
> lpush letter "b"
(integer) 2
> lpush letter "c"
(integer) 3
> lrange letter 0 -1
1) "c"
2) "b"
3) "a"

> rpush letter "a"
(integer) 4
> rpush letter "b"
(integer) 5
> rpush letter "c"
> lrange letter 0 -1
1) "c"
2) "b"
3) "a"
4) "a"
5) "b"
6) "c"

    头部和尾部弹出元素

    lpop key

    rpop key

    > lpop letter
"c"
> lpop letter
"b"
> lrange letter 0 -1
1) "a"
2) "a"
3) "b"
4) "c"

> rpop letter
"c"
> rpop letter
"b"
> lrange letter 0 -1
1) "a"
2) "a"

    索引操作
    索引需要对全部list进行遍历，性能会随着元素个数的增大而变差

    lrange key start stop

    lindex key index

    ltrim key start stop

    len key

    > rpush letter b c
(integer) 4
> lrange letter 0 -1
1) "a"
2) "a"
3) "b"
4) "c"
> lindex letter 2
"b"
> ltrim letter 0 -2
OK
> lrange letter 0 -1
1) "a"
2) "a"
3) "b"
> llen letter
(integer) 3

    插入

    insert key BEFORE|AFTER pivot value

    > linsert letter before b c
(integer) 4
> linsert letter after a d
(integer) 5
> lrange letter 0 -1
1) "a"
2) "d"
3) "a"
4) "c"
5) "b"

    修改

    set key index value

    > lset letter 2 B
OK
> lrange letter 0 -1
1) "a"
2) "d"
3) "B"
4) "c"
5) "b"

    内部编码

    1. ziplist（压缩列表）：小于3.2版本，当元素个数小于list-max-ziplist-entries配置（默认512个），同时每个元素的值长度都小于list-max-ziplist-value配置（默认64字节）
    2. linkedlist（链表）：小于3.2版本，不满足ziplist的条件
    3. quicklist：Redis 3.2版本，以一个ziplist为节点的linkedlist
    > object encoding letter
"quicklist"

    hash (哈希)

    hash是一个string类型的field和value的映射表。 它适合用于存储对象，它是无序的，不能使用索引操作。

    哈希

    hash命令

    设置

    hset key field value

    > hset user:1 name zhangSan
(integer) 1
> hset user:1 age 18
(integer) 1

    获取和获取所有的field-value

    hget key field

    hgetall key

    > hget user:1 name
"zhangSan"
> hgetall user:1
1) "name"
2) "zhangSan"
3) "age"
4) "18"

    删除

    hdel key field [field ...]

    > hdel user:1 age
(integer) 1
> hdel user:2 age
(integer) 0

    长度

    hlen key

    > hlen user:1
(integer) 1

    批量设置

    hmset key field value [field value ...]

    > hmset user:2 name liSi age 23
OK
> hmget user:2 name age
1) "liSi"
2) "23"
> hlen user:1
(integer) 1
> hlen user:2
(integer) 2

    是否存在

    hexists key field

    > hexists user:2 name
(integer) 1
> hexists user:2 city
(integer) 0

    所有的field和所有的value

    hkeys key

    hvals key

    > hkeys user:1
1) "name"
> hkeys user:2
1) "name"
2) "age"
> hvals user:1
1) "zhangSan"
> hvals user:2
1) "liSi"

    内部编码

    1. ziplist（压缩列表）：当元素个数小于hash-max-ziplist-entries配置（默认512个）和每个元素大小小于hash-max-ziplist-value配置（默认64字节）时
    2. hashtable（哈希表）：不满足ziplist条件时
    > object encoding user:1
"ziplist"

    修改配置文件hash-max-ziplist-entries为5

    > hmset test t1 v1 t2 v2 t3 v3 t4 v4 t5 v5 t6 v6
OK
> object encoding test
"hashtable"

    set（集合）

    用来保存多个字符串元素，无序的，不能有重复元素，不能使用索引下标获取元素。一个集合可以存储2^32-1个元素。

    集合

    set命令

    增加

    add key member [member ...]

    > sadd user:1:tag it music news
(integer) 3
> sadd user:1:tag bike news
(integer) 1

    删除

    srem key member [member ...]

    > srem user:1:tag bike
(integer) 1

    个数

    scard key

    > scard user:1:tag
(integer) 3

    是否存在

    sismember key member

    > sismember user:1:tag bike
(integer) 0
> sismember user:1:tag it
(integer) 1

    随机返回指定个数

    srandmember key [count]

    > srandmember user:1:tag
"news"
> srandmember user:1:tag 3
1) "news"
2) "music"
3) "it"

    随机弹出

    spop key [count]

    > spop user:1:tag
"news"
> srandmember user:1:tag 3
1) "music"
2) "it"

    所有个数

    smembers key

    > smembers user:1:tag
1) "music"
2) "it"

    交集

    sinter key [key ...]

    > sinter user:1:tag user:2:tag
1) "music"
2) "it"

    并集

    sunion key [key ...]

    > sunion user:1:tag user:2:tag
1) "music"
2) "java"
3) "run"
4) "it"

    差集

    sdiff key [key ...]

    > sdiff user:1:tag user:2:tag
(empty list or set)
> sadd user:1:tag sleep
(integer) 1
> sdiff user:1:tag user:2:tag
1) "sleep"
> sdiff user:2:tag user:1:tag
1) "java"
2) "run"

    内部编码

    1. intset（整数集合）：元素都是整数和元素个数小于set-max-intset-entries配置（默认512个）时
    2. hashtable（哈希表）：不满足intset时
    > object encoding user:1:tag
"hashtable"

> sadd numbers 1 2 3 4 5
(integer) 5
> object encoding numbers
"intset"

    zset（有序集合）

    zset保证了元素不能重复，每个元素都有一个分数（score）作为排序的依据。

    有序集合

    zset命令

    添加

    zadd key [NX|XX] [CH] [INCR] score member [score member ...]

    > zadd books 8.2 "Redis in Action"
(integer) 1
> zadd books 9.3 "Effective Java: Second Edition : Java"
(integer) 1
> zadd books 9.1 "Think in Java"
(integer) 1
> zadd books 9.3 "Python Cookbook" 9.0 "Effective Python"
(integer) 2

    个数

    zcard key

    > zcard books
(integer) 5

    升序返回范围的成员

    zrange key start stop [WITHSCORES]

    > zrange books 0 -1
1) "Redis in Action"
2) "Effective Python"
3) "Think in Java"
4) "Effective Java: Second Edition : Java"
5) "Python Cookbook"

> zrange books 2 5
1) "Think in Java"
2) "Effective Java: Second Edition : Java"
3) "Python Cookbook"

    升序返回成员时带上分数

    > zrange books 0 -1 withscores
 1) "Redis in Action"
 2) "8.1999999999999993" 
 3) "Effective Python"
 4) "9"
 5) "Think in Java"
 6) "9.0999999999999996"
 7) "Effective Java: Second Edition : Java"
 8) "9.3000000000000007"
 9) "Python Cookbook"
10) "9.3000000000000007"

> zrange books 2 5 withscores
1) "Think in Java"
2) "9.0999999999999996"
3) "Effective Java: Second Edition : Java"
4) "9.3000000000000007"
5) "Python Cookbook"
6) "9.3000000000000007"
    1. 精度问题：内部 score 使用 double 类型进行存储，所以存在小数点精度问题
    2. withscores:带上分数

    降序

    zrevrange key start stop [WITHSCORES]

    > zrevrange books 0 -1 withscores
 1) "Python Cookbook"
 2) "9.3000000000000007"
 3) "Effective Java: Second Edition : Java"
 4) "9.3000000000000007"
 5) "Think in Java"
 6) "9.0999999999999996"
 7) "Effective Python"
 8) "9"
 9) "Redis in Action"
10) "8.1999999999999993"

    指定value的score

    zscore key member

    > zscore books "Think in Java"
"9.0999999999999996"

    根据score的数值区间升序

    zrangebyscore key min max [WITHSCORES] [LIMIT offset count]

    > zrangebyscore books 0 9.1 withscores
1) "Redis in Action"
2) "8.1999999999999993"
3) "Effective Python"
4) "9"
5) "Think in Java"
6) "9.0999999999999996"

    根据score的数值区间降序

    zrevrangebyscore key max min [WITHSCORES] [LIMIT offset count]

    > zrevrangebyscore books 9.1 0  withscores
1) "Think in Java"
2) "9.0999999999999996"
3) "Effective Python"
4) "9"
5) "Redis in Action"
6) "8.1999999999999993"

    根据score的数值降序输出所有元素

    > zrevrangebyscore books +inf -inf  withscores
 1) "Python Cookbook"
 2) "9.3000000000000007"
 3) "Effective Java: Second Edition : Java"
 4) "9.3000000000000007"
 5) "Think in Java"
 6) "9.0999999999999996"
 7) "Effective Python"
 8) "9"
 9) "Redis in Action"
10) "8.1999999999999993"
    1. +inf 正无穷
    2. -inf 负无穷

    删除

    zrem key member [member ...]

    > zrem books "Effective Java: Second Edition : Java"
(integer) 1

    增加分数

    zincrby key increment member

    > zincrby books 2  "Redis in Action"
"10.199999999999999"
> zincrby books -1  "Redis in Action"
"9.1999999999999993"

    交集

    zinterstore destination numkeys key [key ...] [WEIGHTS weight] [AGGREGATE

    > zadd textbooks 8 "chinese" 9 "english" 9.5 "mathematics"
(integer) 3
> zadd textbooks 9.2 "Think in Java"
(integer) 1

> zrange books 0 -1
1) "Redis in Action"
2) "Effective Python"
3) "Think in Java"
4) "Python Cookbook"
> zrange textbooks 0 -1
1) "chinese"
2) "english"
3) "Think in Java"
4) "mathematics"

> zinterstore newbooks 2 books textbooks
(integer) 1
> zrange newbooks 0 -1
1) "Think in Java"

    并集

    zunionstore destination numkeys key [key ...] [WEIGHTS weight] [AGGREGATE

    > zunionstore newUnionbooks 2 books textbooks
(integer) 7
> zrange newUnionbooks 0 -1
1) "chinese"
2) "Redis in Action"
3) "Effective Python"
4) "english"
5) "Python Cookbook"
6) "mathematics"
7) "Think in Java"

    内部编码

    1. ziplist（压缩列表）：元素个数小于zset-max-ziplist-entries配置（默认128个）和元素长度小于zset-max-ziplist-value配置（默认64B）时
    2. skiplist（跳跃表）：不满足ziplist时
    > object encoding books
"ziplist"

    结语

    本人深知水平有限，欢迎指正本文错误之处。

    参考资料

    《Redis 实战》

    《Redis 开发与运维》

    《Redis 深度历险：核心原理与应用实践》

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  • 原文地址：https://www.cnblogs.com/imeng/p/11305235.html
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