Introduction to redis and explanation of data types

Official website

Official website ：http://www.redis.cn/

Concept

Open source high performance key value pair database

16 A database

Port number   6379

（ The range of port numbers is from 0 To 65535

1023 The following ports have been assigned to some commonly used applications ）

Enter the client

redis-cli

password

Check the password ：CONFIG get requirepass

Set the password ：CONFIG set requirepass "123456"

Input password ：AUTH "123456"

data type

Basic data type ：string,hash,list,set,zset

Special data types ：Geo,Bitmap,Hyperloglog

character string ：string

It's simple. Key-Value type

What is the maximum storage capacity of a string type value ？ 512M

scene ： Distributed lock , Distributed session, seckill , Count

set key val

get key

mget key key key

del key

incr key： Self increasing

decr key： Self reduction

incrby key 3： Self increasing 3

decrby key 3： Self reduction 3

keys *： View all key

Hash ：hash

yes string Type of key and val Mapping table , Hash hash hash table

scene ： Store object data （ User information ）

hset Hash name Key name value

hget Hash name Key name

hmset Hash name Key name value Key name value

hmget Hash name Key name Key name

hgetall Hash name ： Get all the key names and values in this hash

hkeys Hash name ： Get all the key names in this hash

hvals Hash name ： Get all the values in this hash

hdel Hash name Key name

hexists Hash name Key name ： Does the key exist , return 1 or 0

hincryby Hash name Key name 3： Self increasing 3

list ：list

Store multiple ordered strings

scene ： Render article list , In general, each user will have their own list of published articles , If you need to show a list of articles , You can use List data type , Not only can the list of articles be ordered but also can be queried according to the index range .

rpush List name value value ： take One or Multiple value push list Of Right end

lpush List name value value ： take One or Multiple value push list Of Left side

rpop List name ： move except and return list most Right end Of Elements

lpop List name ： move except and return list most Left side Of Elements

lindex List name Subscript ： Returns the value of the specified subscript in the list （ Subscript from 0 Start ）

lrange List name Start subscript End subscript ： Returns the value of the specified subscript range in the list

ltrim List name Start subscript End subscript ： Only keep the value of the subscript range

blpop List name List name Number of seconds ： Move at the specified time except and return The first non empty list most Left side Of Elements

rpoplpush List name List name ： Pop up the right most element from the first list , Put this element Push the leftmost end of the second list

brpoplpush List name List name Number of seconds ：rpoplpush Blocking version of , It will not end until the specified number of seconds

unordered set ：set

Duplicate elements are not allowed , And it's out of order

scene ： Record unique value ： For example, login. ip, ID number . Add tags ： Calculate user preferences and other data through the intersection and union of labels , Common friends .

sadd Collection name value value

srem Collection name value value ： Delete one or more values

sismember Collection name value ： Check whether the value exists in the set

scard Collection name ： Returns the number of values in the set

smembers Collection name ： Return all values in the set

srandmember Collection name 3： Return randomly from the set 3 Elements .（3 Is a positive number , The returned element will not repeat ; If it is -3, The random elements returned may be repeated ）

spop Collection name ： Delete one at random

smove Collection name Collection name value ： Move a value from the first set to the second set

sdiff Collection name Collection name Collection name ： Get existence and the first set , But there is no value with other sets （ Subtraction operation ）

sdiffstore Specify the collection name Collection name Collection name Collection name ： Will exist with the first set , But there is no value with other sets moved to the specified set

sinter Collection name Collection name Collection name ： Get the values of all sets that exist at the same time （ Intersection operation ）

sinterstore Specify the collection name Collection name Collection name Collection name ： Move the values of all sets that exist at the same time to the specified set

sunion Collection name Collection name Collection name ： Get the values of all sets （ Union operation ）

sunionstore Specify the collection name Collection name Collection name Collection name ： Move the values of all sets to the specified set

Ordered set ：zset

A set of ordered data with unique key value pairs

scene ： Ranking List ： According to the integral order from small to large . Get a range of data ： The test 80-100 Minute data

zadd Collection name score value value score value value

zrem Collection name value value ： Delete

zremrangebyrank Collection name End value Starting value ： Delete the value of the set ranking between a certain range

zremrangebyscore Collection name End value Starting value ： Delete the collection score Values between certain ranges

zincrby Collection name 3 value ： Give a set of values score Add 3

zcard Collection name ： Number

zcount Collection name Starting value End value ： Get a collection score The number of values in a certain range

zscore Collection name value ： Get a value in the set score value

zrank Collection name value ： Get the ranking of a value in the set （ from 0 Start ）（ The smallest ranking is 0）

zrevrank Collection name value ： Press score Values range from large to small , Get the ranking of a certain value

zrange Collection name Starting value End value withscores： Get the value of the set ranking between a certain range （ From small to large ）, If you add withscores, Will also get score value

zrevrange Collection name Starting value End value withscores： Get the value of the set ranking between a certain range （ From big to small ）, If you add withscores, Will also get score value

zrangebyscore Collection name Starting value End value withscores limit Start subscript End subscript ： aggregate score Values between certain ranges （ From small to large ）, If you add withscores, Will also get score value , If you add limit Start subscript End subscript , Is to get the value of a range based on the order , You can perform paging query

zrevrangebyscore Collection name End value Starting value withscores Start subscript End subscript ： aggregate score Values between certain ranges （ From big to small ）, If you add withscores, Will also get score value , If you add limit Start subscript End subscript , Is to get the value of a range based on the order , You can perform paging query

zinterstore Specify the collection name The number of subsequent set names Collection name Collection name ： Intersection of evaluation , Then save the intersection result in the specified set （score Values are added ）

zunionstore Specify the collection name The number of subsequent set names Collection name Collection name ： Evaluation union , Then save the union result to the specified set （score Values are added ）

Location ：Geo（Geospatical）（ Version for ：Redis3.2）

GEO The underlying implementation principle is actually Zset, We can use Zset Command to operate GEO

scene ： location 、 Check out the people around 、 Friends' positioning 、 Taxi distance calculation

geoadd Collection name longitude dimension Place names longitude dimension Place names

geopos Collection name Place names ： Returns the position of all the given location elements （ Longitude and latitude ）

geodist Collection name Place names Place names Company ： Returns the linear distance between two given positions （ The default unit is m, The unit also has km mi( miles ) ft( Inch )）

georadius Collection name longitude latitude radius Company withdist withcoord withhash asc/desc count 2： Centered on a given latitude and longitude , Find the elements in a certain radius （withdist Is to return the distance between the position element and the center ）（withcoord Is to return the longitude and dimension of the location element together , That is, display the location information of others ）（withhash In order to 52 Bit signed integer form , Return the location element through the original geohash Encoded ordered set score . This option is mainly used for underlying applications or debugging , It doesn't really work .）（asc/desc：asc According to the position of the center , Return the location element in a near to far way ,desc According to the position of the center , Return the location elements from far to near ）（count 2 Is to designate several places to return ）

georadiusbymember Collection name Place names radius Company ： Find the elements in the specified range , The center point is determined by a given location element （ Take the current place name as the center , Find the elements within the radius ）

geohash Collection name Place names Place names ： Returns the... Of one or more positional elements Geohash character string （ Convert two-dimensional latitude and longitude into one-dimensional string , If the two strings are closer , So the closer we get ）（11 Characters ）

Bitmap scene ：Bitmap

Bitmap It's a bitmap , data structure , It's all operating bits to record , Only 0 and 1 Two states

scene ： Statistics user information 、 active 、 Inactive 、 Sign in 、 Not logged in 、 Punch in and wait … Both states can be used Bitmap

setbit Collection name Key name value ：（ The value can only be 0 perhaps 1）

getbit Collection name Key name ： Get the value of a key in the collection

bitcount Collection name ： Get the value in the set as 1 The number of keys of

Base Statistics ：Hyperloglog

The number of non repeating elements in a repeatable set is the cardinality

The traditional way ： Use set Protect the user's ID, And then you can count set The number of elements in as a standard judgment , This way, if you save a large number of users id, It will be more troublesome . Our purpose is to count , Instead of storing users id.

advantage ： The memory occupied is fixed ,2^64 Technology of different elements , It only costs 12KB Memory . If you want to compare from the memory point of view ,Hyperloglog First choice

If fault tolerance is allowed , Then be sure to use Hyperloglog; If fault tolerance is not allowed , Just use set Or your own data type .（ Fault tolerance is when data appears in the system for various reasons 、 When the file is damaged or lost , The system can automatically restore these damaged or lost files and data to the state before the accident , A technology that enables a system to operate continuously and normally , It's very simple ）

scene ： Page Statistics , Web page UV（ A person visits a website many times , But still count as a person ）

pfadd Collection name value value ： Add one or more elements

pfcount Collection name ： Count the number of cardinalities in the set

pfmerge New collection name Collection name Collection name ： Merge the elements of the collection , And eliminate the repeated elements , Generate a new set