List chain / list structure

Lpush key value

Function: insert a value into the head of the link

Rpop key

Function: return and delete the element at the end of the list

Rpush,lpop: no explanation

Lrange key start stop (starting at 0)

Lrange key 6 6 views data with index 6

Lrange key 2 5 views data with indexes from 2 (including 2) to 5 (including 5)

Function: returns the elements in [start, stop] in the linked list

Rule: the left starts at 0 and the right starts at-1 (0-1 selects all elements)

Lrem key count value

View 5 pieces of data on the right side of the list:

Lrange key-5-1

Purpose: remove the value value from the key linked list

Note: end after deleting the absolute value of count (value)

Delete Count > 0 from the header

Count llen task

(integer) 3

Redis 127.0.0.1 purl 6379 >

L × × × ert key after | before search value

Function: look for 'search',' in the key linked list and before the search value | after. Insert value

Note: once a search is found, the command ends, so multiple value will not be inserted.

There are multiple inserts of values being queried:

Rpoplpush source dest

Function: take out the tail of source and put it on the head of dest

And return the cell value

Scenario: task + bak double linked list completes the security queue

Business logic:

1:Rpoplpush task bak

2: receive the return value and do business processing

3: if successful, rpop bak clears the task. If unsuccessful, get the task from the bak table next time.

Brpop, blpop key timeout

Function: wait for the tail / header element of the key to pop up

Timeout is the wait timeout

If timeout is 0, wait forever

Scenario: long polling Ajax, can be used when chatting online

Note:

Since a list can store millions of pieces of data, never rashly list all the data in a list, otherwise it may result in a large amount of data output and instantly deplete the system's 1max 0 resources.

It should be: first check the length of the list, if it is determined that the amount of data is small, then list all the values; if the amount of data is large, you can use the index to view the first few pieces of data and the last few pieces of data.