NoSQL database redis installation

Installed version

• 6.2.1 for Linux（redis-6.2.1.tar.gz）
• Don't think about it windows Environment Redis Support for

Installation steps

preparation ： Download and install the latest version of gcc compiler

install C The compiling environment of language

yum install centos-release-scl scl-utils-build

yum install -y devtoolset-8-toolchain

scl enable devtoolset-8 bash

test gcc edition

gcc --version

download redis-6.2.1.tar.gz discharge /opt Catalog

Unpack the command ：tar -zxvf redis-6.2.1.tar.gz

After decompression, enter the directory ：cd redis-6.2.1

stay redis-6.2.1 Execute... Again in the directory make command （ Just compile ）

If not ready C Language compiling environment ,make  Meeting Report errors —Jemalloc/jemalloc.h： There is no such document

Solution ： function make distclean

stay redis-6.2.1 Execute... Again in the directory make command （ Just compile ）

skip make test Carry on : make install

The installation directory ：/usr/local/bin

View the default installation directory ：

redis-benchmark: Performance testing tools , You can run it in your own book , Look at the performance of your book

redis-check-aof： Fix the problem AOF file ,rdb and aof Later on

redis-check-dump： Fix the problem dump.rdb file

redis-sentinel：Redis Cluster use

redis-server：Redis Server start command

redis-cli： client , Operation entrance

The front desk starts （ Not recommended ）

The front desk starts , The command line window cannot be closed , Otherwise, the server stops

Background start （ recommend ）

Backup redis.conf

Copy a redis.conf Go to other directories

cp  /opt/redis-3.2.5/redis.conf  /etc

Background startup settings daemonize no Change to yes

modify redis.conf(282 That's ok ) The document will contain daemonize no Change to yes, Let the service start in the background

Redis start-up

redis-server /etc/redis.conf

Use the client to access ：redis-cli

Multiple ports can ：redis-cli -p6379

Test verification ： ping

Redis close

Single instance close ：redis-cli shutdown

 

You can also enter the terminal and then close it

Multi instance shutdown , The specified port is closed ：redis-cli -p 6379 shutdown

Redis key (key)

Add data

  set k1 "123"

keys * View all of the current library key    ( matching ：keys *1)

exists key Judge a certain key Whether there is

type key View your key What type is it

del key        Delete specified key data

unlink key    according to value Select non blocking delete

Only will keys from keyspace Delete from metadata , The real deletion will be done asynchronously later .

expire key 10   10 Second ： For a given key Set expiration time

ttl key See how many seconds are left to expire ,-1 Never expire ,-2 Indicates that it has expired

select Command switch database

dbsize Check the... Of the current database key The number of

flushdb Empty the current library

flushall Kill all the warehouses

Common commands

set   <key><value> Add key value pair

*NX： When the database key When there is no , Can be key-value Add database

*XX： When the database key In existence , Can be key-value Add database , And NX Parameters are mutually exclusive

*EX：key Time out seconds for

*PX：key Timeout milliseconds for , And EX Mutually exclusive

get   <key> Query the corresponding key value

append  <key><value> Will be given <value> Append to the end of the original value

strlen  <key> Get the length of the value

setnx  <key><value> Only in key When there is no     Set up key Value

incr  <key>

take key Increase the value of the number stored in 1

Can only operate on numeric values , If it is empty , The new value added is 1

decr  <key>

take key The number stored in minus 1

Can only operate on numeric values , If it is empty , The new value added is -1

incrby / decrby  <key>< step > take key Increase or decrease the number value stored in . Custom step size .

Atomicity So-called atom Operation means Operations that are not interrupted by thread scheduling ; Once this operation begins , It runs until the end , There won't be any context switch （ Switch to another thread ）. （1） In a single thread , Operations that can be performed in a single instruction can be considered as " Atomic manipulation ", Because interrupts can only occur between instructions . （2） In multithreading , Can't be used by other processes （ Threads ） The interrupted operation is called atomic operation . Redis The atomicity of a single command is mainly due to Redis The single thread . Case study ： java Medium i++ Is it atomic operation ？ No i=0; Two threads are connected to i Conduct ++100 Time , What is the value ？ 2~200 i=0 i++ i=99     i=1     i++ i=2 i=0   i++ i=1   i++ i=100

mset  <key1><value1><key2><value2>  .....

Set one or more... At the same time key-value Yes  

mget  <key1><key2><key3> .....

Get one or more at the same time value  

msetnx <key1><value1><key2><value2>  .....

Set one or more... At the same time key-value Yes , If and only if all given key It doesn't exist .

Atomicity , If one fails, all fail

 

getrange  <key>< The starting position >< End position >

Get the range of values , similar java Medium substring, Front bag , Back bag

setrange  <key>< The starting position ><value>

use <value>   overwrite <key> String value stored , from < The starting position > Start ( Index from 0 Start ).

setex  <key>< Expiration time ><value>

While setting the key value , Set expiration time , Unit second .

getset <key><value>

Trade in new for old , Set the new value and get the old value .