Redis Link Linked list structure

Role: Inserting values into the link header

Rpop Key

Function: Returns and deletes the chain footer element

Lrange Key Start  stop

Function: Returns the element in the list [Start, stop]

Rule: The left number starts at 0 and the right number starts at 1

Lrem Key Count value

Function: Removes the value from the key linked list

Note: Delete the absolute value of count after the end of value

Count>0 Remove from table header

Count<0 Delete from footer

LTrim Key Start stop

function : Cut Key the corresponding link , Cut [Start,stop] some , and re-assign the paragraph to Key

Lindex Key Index

function : return Index the value on the index ,

as lindex Key 2

Llen Key

function : count the number of elements in a linked table

Redis 127.0.0.1:6379> Llen Task

(integer) 3

Redis 127.0.0.1:6379>

Linsert  key After|before Search value

function: in theKeylinked list to find' Search ',and inSearchvalue before|after,.Insertvalue

Note : once you find a Search after , the order is over. , Therefore, you will not insert multiple value　　

Rpoplpush Source Dest

+ Bak doubly linked list complete secure queue Task List                             bak listing         1   1   1                         1   1   1      business logic:1: Rpoplpush Task bak2: Receives the return value and does business processing 3: If successful, Rpop bak clears the task. If unsuccessful, take the task from the Bak table next time

Brpop, Blpop  key timeout

function : waiting to pop up Key the tail / Head Element ,

Timeout to wait for a time-out

if Timeout to be 0, is waiting

Scenario : long polling Ajax, when chatting online , can use

Setbit Real-world scenarios: 100 million users, each user login/do any action, remember as active today, otherwise recorded as inactive Weekly: award-winning active Users: Monthly commentary for 7 consecutive days, etc... Idea: Userid DT active1         -- -- -  11        --0726   1if it is placed in a table,1: The table grows sharply,2: To use the group, sum operation, the calculation is slower: Bitmap method bit-mapLog0721: '011001...............0' ... log0726: '011001...............0' Log0727: '0110000.............1'1: Log User login: Generate a bitmap daily by date, after the user logs on, the bit value on the USER_ID bit is set to 12: Calculates the 1-week bitmap and the 1-bit, which is the user Redis for continuous login127.0.0.1:6379> Setbit Mon100000000 0(integer)0Redis127.0.0.1:6379> Setbit Mon3 1(integer)0Redis127.0.0.1:6379> Setbit Mon5 1(integer)0Redis127.0.0.1:6379> Setbit Mon7 1(integer)0Redis127.0.0.1:6379> setbit Thur100000000 0(integer)0Redis127.0.0.1:6379> setbit Thur3 1(integer)0Redis127.0.0.1:6379> setbit Thur5 1(integer)0Redis127.0.0.1:6379> setbit Thur8 1(integer)0Redis127.0.0.1:6379> Setbit Wen100000000 0(integer)0Redis127.0.0.1:6379> Setbit Wen3 1(integer)0Redis127.0.0.1:6379> Setbit Wen4 1(integer)0Redis127.0.0.1:6379> Setbit Wen6 1(integer)0Redis127.0.0.1:6379>bitop and res Mon Feb wen (integer)12500001For example, the advantages:1: Save space, 100 million people daily landing situation, with 100 million bit, about 1200WByte, about 10M characters can be expressed2: Convenient calculation

　　

LTrim Key Start stop

Redis Link Linked list structure