一文了解：Redis基础类型

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

mac\linux：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
int 8个字节的长整型
embstr 小于等于39个字节的字符串
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
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）
linkedlist（链表）：小于3.2版本，不满足ziplist的条件
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
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
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
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
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"
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
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"
+inf 正无穷
-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
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
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》