The five basic data structures of redis are in-depth and application scenarios

Redis The five basic data structures are in-depth 、 Application scenarios

0. Business data

1.string

String The type is Redis The most commonly used type in , Internal implementation is through SDS（Simple Dynamic String ） To store the .SDS Be similar to Java Medium ArrayList, The frequent allocation of memory can be reduced by pre allocating redundant space .
Stored data ： Single data , The simplest type of data storage , It is also the most commonly used data storage type
The format of data storage ： One storage space holds one data
Store content ： You usually use strings , If the string is presented as an integer , It can be used as a digital operation

1.2String Basic operation

1.3String Application scenarios

String The practical application scenarios of are more extensive ：
1. Caching function ：String String is the most commonly used data type , not only Redis, Every language is the most basic type , therefore , utilize Redis As caching , With other databases as the storage layer , utilize Redis Support for high concurrency , It can greatly speed up the reading and writing speed of the system 、 And reduce the pressure on the back-end database .
2. Counter ： Many systems use Redis As the real-time counter of the system , It can quickly realize the function of counting and querying . And the final data results can be stored permanently in the database or other storage media at a specific time .
3. Share users Session： The user refreshes the interface again , You may need to access the data to log in again , Or visit the page cache Cookie, But it can be used Redis The user's Session centralized management , In this mode, we only need to guarantee Redis High availability , Every time a user Session The update and acquisition of can be completed quickly . Greatly improved efficiency .//

1.4set And mset Choice problem

By the time 3 Part of it is made up of ： The client sends instructions to redisd Time for +redis Execution time +redis Time to return the result to the client ;
Let's assume The client sends instructions to redisd Time for ==redis Time to return the result to the client

1.5.string matters needing attention

1.6string As a numerical operation

1.7 Application scenarios - Optimize table splitting operation

Tip1: redis Used to control the database table primary key id, Provide generation strategy for database table primary key , Ensure the uniqueness of the primary key of the database table
This scheme is applicable to all databases , And support database cluster

1.8 Application scenarios - Popular product recommendation

Tip2:redis Control the lifecycle of data , Control business behavior through data failure , Applicable to all operations with time limited control

1.9 Application scenarios - Weibo fans

Tip3:redis It can be applied to all kinds of structured and unstructured high heat data access acceleration

2.Hash

2.1Hash Introduce

This is similar Map A structure of , In general, structured data can be used , Like an object （ The premise is that this object does not nest other objects ） To cache in Redis in , And every time I read and write the cache , It can be operated Hash A field in .
But the scene is a little more single , Because now many objects are more complex , For example, your product object may contain many attributes , There are also objects . I don't use so many scenes myself .

2.2Hash Basic operation

2.3Hash Application scenarios

This is similar Map A structure of , In general, structured data can be used , Like an object （ The premise is that this object does not nest other objects ） To cache in Redis in , And every time I read and write the cache , It can be operated Hash A field in .

2.4Hash matters needing attention

2.5 Application scenarios - E-commerce website shopping cart design and implementation

Tip4:redis Applied to the design of shopping cart data storage

2.6 Application scenarios - Rush to buy restricted goods

Tip5:redis It's applied to rush buying , Limited purchase 、 A limited number of coupons will be issued 、 Data storage design of activation code and other services

2.7 Application scenarios -string Store the object （json） And hash Store the object

3.List

3.1List Introduce

3.2List Basic operation

3.3List Application scenarios

List There is a sequence table , This one can play a lot of tricks .
For example, through List Store some list data structures , Similar to fan list 、 Comment list of articles and so on .
For example, through lrange command , Read elements in a closed interval , Can be based on List Realize paging query , This is a great feature , be based on Redis Simple high performance paging , You can do things like Weibo that pull down and page continuously , High performance , One page at a time .
For example, we can make a simple message queue , from List Head in , from List Get it out of the ass .
List It is the data structure that we often use in the development process , Hot data, let alone .
1. Message queue ：Redis Link list structure of , Blocking queues can be easily implemented , You can use the command composition of left in right out to complete the design of the queue . such as ： Producers of data can access Lpush Command to insert data from the left , Multiple data consumers , have access to BRpop Command blocked “ rob ” Data at the end of the list .
2. Application of article list or data page display .
such as , A list of articles from our popular blog sites , When there are more and more users , And every user has their own list of articles , And when there are many articles , All need to be displayed in pages , Consider using Redis A list of , The list is not only ordered, but also supports getting elements according to the scope , It can perfectly solve the paging query function . Greatly improve query efficiency

3.4list matters needing attention

3.5 Application scenarios - Friends circle like

Tip6:redis Applied to data control with sequence of operations

3.6 Application scenarios - Fan following list

Tip7:redis Apply to the latest news display

4.Set

4.1Set Introduce

Set Is an unordered set , It's the kind that will automatically go heavy .
Based on the direct Set Throw in the data that needs to be de duplicated in the system , It's automatic .
Can be based on Set Play together 、 Combine 、 Operation of difference set , Like intersection , We can make a whole intersection of two people's friends list , Let's see who our mutual friends are ？ Right .
Anyway, there are many scenes , Because the contrast is fast , It's easy to operate , Two queries one Set Get it done .

4.2Set Basic operation

4.3Set Application scenarios

4.4Set matters needing attention

4.5 Application scenarios - Hot recommendation

Tip8:redis It is applied to random recommendation information retrieval , For example, hot song list recommendation , Hot news recommendation , Hot tourist routes , application APP recommend , Big V Recommendation, etc

4.6 Application scenarios - Association search

Tips 9：redis It is applied to the association search of similar information , Second degree association search , Deep association search
1. Show common concern （ once ）
2. Show common friends （ once ）
3. By the user A set out , Get friends B A list of your friends' information （ once ）
4. By the user A set out , Get friends B List of shopping lists for （ Two degrees ）
5. By the user A set out , Get friends B Game recharge list for （ Two degrees ）
Tips 10：redis Apply to the consolidation of non duplicate data of the same type 、 Take intersection operation

4.7 Application scenarios - Website visit to remove duplication

Tip11:redis Fast de duplication for the same type of data

4.9 Application scenarios - Black and white list

Tip12:redis Apply to service settings based on blacklist and whitelist settings

5.SortedSet

5.1SortedSet Introduce

Sorted set Is the sort of Set, De duplication but sorting , Give a score when you write it in , Auto sort by score .
The usage scenario of ordered set is similar to that of set , however set Sets are not automatically ordered , and Sorted set You can use scores to sort members , And it's sorted when you insert . So when you need an ordered and non repetitive list of collections , You can choose Sorted set Data structures as options .
1. Ranking List ： Orderly collection of classic use scenarios . For example, video websites need to rank videos uploaded by users , The maintenance of the list may be in many ways ： According to the time 、 According to the amount of play 、 According to the number of likes, etc .
2. use Sorted Sets To make a weighted queue , For example, ordinary news score by 1, Important news score by 2, Then the worker thread can choose to press score To get the task . Give priority to important tasks .
3. Microblogging Trending , There's a heat value behind it , In front of it is the name

5.2SortedSet Basic operation

5.3SortedSet Application scenarios

5.4SortedSet matters needing attention

5.5 Application scenarios - Audition vote

Tip13:redis Applied to the ranking of the counter combination sorting function

5.6 Application scenarios - Membership expires

Tip14:redis It is applicable to scheduled task execution sequence management or task expiration management

5.7 Application scenarios - Task weight

Tip15: Apply to immediate tasks / Message queue execution management

6.redis Business scenario - Voice call

Tip16：redis Service control applied to time limited settlement by time

7.redis Business scenario - Chat top

Tips17:redis Applied to data manipulation based on time sequence , Instead of focusing on the specific time

8.redis Application scenarios

Tips 1：redis Used to control the database table primary key id, Provide generation strategy for database table primary key , Ensure the uniqueness of the primary key of the database table
Tips 2：redis Control the lifecycle of data , Control business behavior through data failure , Applicable to all operations with time limited control
Tips 3：redis It can be applied to all kinds of structured and unstructured high heat data access acceleration
Tips 4：redis Applied to the design of shopping cart data storage
Tips 5：redis It's applied to rush buying , Limited purchase 、 A limited number of coupons will be issued 、 Data storage design of activation code and other services
Tips 6：redis Applied to data control with sequence of operations
Tips 7：redis Apply to the latest news display
Tips 8：redis It is applied to random recommendation information retrieval , For example, hot song list recommendation , Hot news recommendation , Hot tourist routes , application APP recommend , Big V Recommendation, etc
Tips 9：redis It is applied to the association search of similar information , Second degree association search , Deep association search
Tips 10：redis Apply to the consolidation of non duplicate data of the same type 、 Take intersection operation
Tips 11：redis Fast de duplication for the same type of data
Tips 12：redis Apply to service control based on blacklist and whitelist settings
Tips 13：redis Applied to the ranking of the counter combination sorting function
Tips 14：redis It is applicable to scheduled task execution sequence management or task expiration management
Tips 15：redis Apply to just in time tasks / Message queue execution management
Tips 16：redis Service control applied to settlement by time
Tips 17：redis Applied to data manipulation based on time sequence , Instead of focusing on the specific time