Redis Express

data type

String( character string )

• redis Of string Can contain any data , such as jpg Picture or serialized object
• string The type is Redis Basic data types ,string The maximum value of type can store 512MB

// Common commands 
set key value	// Definition 
get key			// obtain 

// Cover key The value after the specified position of the stored string  
// It is worth noting that this operation will not refresh the string life cycle , It's an updated method 
SETRANGE KEY_NAME OFFSET（ Location ） VALUE（ value ）

// Get string length 
STRLEN KEY_NAME

Hash( Hash )

• Redis hash It's a key value (key=>value) The collection , He will be value Further divided into field And value Two parts , So as to carry out CURD

// Define and get 
hset key name1 value1 name2 value2
hget key name1					// Get the first value 
hget key name2					// Take the second value 

// To judge the existence of 
HEXISTS KEY_NAME FIELD_NAME 	// The return is bool value 

// Get the value in the hash table 
HGETALL KEY_NAME 				// The return is key value Staggered array 

// Get the number of fields in the hash table , That is, there are several key value pairs 
HLEN KEY_NAME 

//Redis HSCAN  The command is used to iterate over key value pairs in the hash table , Often used in fuzzy search 
HSCAN key cursor [MATCH pattern] [COUNT count]
// But because the cursor will change after each search , One solution is to COUNT Then specify how many to return , Or direct violence gives a larger value 
// The problem is that duplicate elements will be returned , So we need a reprocess 
// Example , To realize fuzzy search ,$search for instance  * high * Count *
hscan laravel_database 0 match $search count 1000

（ The graph is Another Redis Visualization software example ）

List( list )

• Sort by insertion order . You can add an element to the head of the list （ On the left L） Or tail （ On the right R）, It's similar to a linked list file

// Deposit in 
LPUSH runoobkey redis
// obtain 
LRANGE runoobkey start stop  
// remove 
LERM key count value 
// Scope delete 
LTRIM KEY_NAME START STOP
// List length 
LLEN KEY_NAME 

Set( aggregate )

• Redis Of Set yes string Unordered collection of type , Element is not repeatable , Quick search
• My usage scenario is based on the preferences of computing users , Browse volume , The amount of collections, etc. will be recommended by all users for videos and articles , Use redis The intersection of sets

// Definition 
SADD key value
// obtain 
SMEMBERS key
// Number 
SCARD KEY_NAME 
// set intersection 
SINTER KEY KEY1..KEYN 
// Take the intersection and store it in DESTINATION_KEY  in 
SINTERSTORE DESTINATION_KEY KEY KEY1..KEYN 
// Gather all the elements 
SMEMBERS key
// Take difference 
SDIFF FIRST_KEY OTHER_KEY1..OTHER_KEYN 
// To differentiate and store 
SDIFFSTORE DESTINATION_KEY KEY1..KEYN 
// Remove Members 
SREM KEY MEMBER1..MEMBERN

zset(sorted set Ordered set )

• Sortable , Element is not repeatable , Quick query , be relative to set One more serial number , Command and set be similar

• All rankings are in ascending order by default

Publish subscribe

• And advanced Stream
• Unfortunately, I haven't actually fought yet redis This function

SUBSCRIBE channel		// Bloggers subscribe to channels 
PUBLISH channel " Published content "	// Users receive published content 

Business

• Bulk operation is sending EXEC command Before being put into the queue cache .
• received EXEC command Then enter transaction execution , Transaction Arbitrary command execution failed , The rest of the orders are still being carried out .
• In the transaction execution process , Command requests submitted by other clients will not be inserted into the transaction execution command sequence .

 MULTI		// Start a transaction 
 ...
 EXEC		// perform 

Other commands

• keys Check the matching template key,key Multiple time searches are slow and occupy threads , It is not recommended to use

• del Delete specified key, It can be more than one , The number of deleted items is returned

• exists Judge whether it exists

• expire to key Set expiration date

  expire key <time(s)>
  

• ttl see key Remaining time among -1 It's permanent ,-2 It doesn't exist

Key Hierarchical structure

• Multiple words are allowed to form a hierarchy , use “:” separate , Form a folder like structure , It will be particularly clear in the visual interface
• for example ：

Cache actual use

• Cache optimization search speed implementation architecture diagram

• What needs attention is the problem of data consistency , In every design to CURD Pay attention to all places mysql and redis The consistency of