The deployment of non relational database Redis, the use of Redis basic commands, Redis master-slave replication, read-write separation, and the persistence of Redis database

Architecture diagram

Install Redis service

tar -xvf redis-2.8.6.tar.gz
cd redis-2.8.6
mkdir /usr/local/redis/etc
cp redis.conf /usr/local/redis/etc/

ps: make error

Execute the command make MALLOC=libc

Modify the profile to start the service

vim /usr/local/redis/etc/redis.conf
daemonize yes
# Running as a daemon does not occupy the shell exchange interface
# Start redis
/usr/local/redis/bin/redis-server /usr/local/redis/etc/redis-server
# Turn off redis
pkill -9 redis-server or killall redis-server

Common Redis commands

5 big data types

  • string
  • hash
  • list
  • set
  • zset
string is the simplest type

A key corresponds to a value, and the string type is binary safe. redis's string can contain any data

hash is a mapping table of field and value of string type

Its addition and deletion operations are 0 (1) average; Hash is especially suitable for storing objects. Compared with storing each field of an object as a single string type, storing an object in hash type will occupy less memory and can access the whole object more conveniently.

List is a linked list structure. Its main functions are push, pop, obtaining all values in a range, etc

In operation, key is understood as the name of the linked list. Redis's list type is actually a two-way linked list in which each child element is of string type. We can add or delete elements from the head or tail of the linked list through push and pop operations.

Set is a set. It is an unordered set of string type.

Set is realized through hash table, including set, intersection and difference sets. Through these operations, we can realize the friend recommendation and blog tag functions in social networking sites. Duplicate values are not allowed in the collection.

zset is an upgraded version of set. It adds an order attribute on the basis of set. This attribute can be specified when adding and modifying elements. After each assignment, zset will automatically adjust the order according to the new value.

It can be understood as a mysql table with two columns, one for value and the other for order. In operation, key is understood as the name of zset.
Key values String operation

ln -s /usr/local/redis/bin/redis-cli /usr/local/bin/redis-cli
# -h IP: connect to the specified redis server
# -p 6379: specify the port of the redis server
# -A password: log in with a password
# -n database number: specifies which database to connect to
# --raw: redis supports storing Chinese> set k1 v1
OK> get k1
"v1"> exists k1
(integer) 1> type k1
string> dbsize
(integer) 1> del k1
(integer) 1> get k1

Command for value operation

  • exists(key): confirm whether a key exists
  • del(key): deletes a key
  • type(key): the type of return value
  • keyrename(oldname, newname): renames the key
  • dbsize: returns the number of key s in the current database
  • expire: set the active time of a key (s)
  • ttl: get the activity time of a key
  • flushdb: deletes all key s in the currently selected database
  • Flush all: delete all key s in all databases

Hash type operation> hmset zhangsan name zhangsan age 18 sex man
OK> hmset lisi name lisi age 25 sex man
OK> hgetall zhangsan
1) "name"
2) "zhangsan"
3) "age"
4) "18"
5) "sex"
6) "man"> hgetall lisi
1) "name"
2) "lisi"
3) "age"
4) "25"
5) "sex"
6) "man"

list operation> rpush zhangsan zhangsan
(integer) 1> rpush zhangsan 18
(integer) 2> rpush zhangsan sex
(integer) 3> lrange zhangsan 0 -1
1) "zhangsan"
2) "18"
3) "sex"> 

set data type> sadd mset 1 2 3 4 5 6
(integer) 6> smembers mset
1) "1"
2) "2"
3) "3"
4) "4"
5) "5"
6) "6"> sadd mset1 zhangsan lisi wangwu
(integer) 3> smembers mset1
1) "wangwu"
2) "zhangsan"
3) "lisi"

Modify redis password

vim /usr/local/redis/etc/redis.conf
requirepass 123456
redis-cli -a 123456
Redis semi persistent RDB
vim /usr/local/redis/etc/redis.server
save 900 1
save 300 10
save 60 10000
# Modify the key once in 900 seconds
# Modify 10 key s in 300 seconds
# Modify 10000 key s in 60 seconds

When the default match is added and takes effect, a file named dump. Will be generated in the / usr/local/redis directory RDB file
Modify the configuration line dbfilename dump RDB can modify the default file name

Redis fully persistent AOF
vim /usr/local/redis/etc/redis.server
appendonly yes
appendfilename appendonly.aof
auto - aof - rewrite- percentage 100
auto - aof - rewrite- min- size 64MB
appendfsync always
# appendfsync everysec
# appendfsync no

appendonly yes: enable AOF persistence.
appendfilename appendonly.aof: AOF persistent save file name.
Auto AOF rewrite percentage 100: when the AOF file size exceeds the percentage of the AOF file size at the time of the last rewrite, it will be rewritten again. If it has not been rewritten before, it will be based on the AOF file size at startup.
Auto AOF rewrite min size 64MB: the minimum AOF file size allowed to be rewritten configures the mechanism that requires the system to refresh the hard disk cache after writing the AOF file.
Appendsync always: synchronization is performed every time a write is performed, which is the safest and slowest.

Redis master-slave copy read-write separation
  1. The master server Maset does not need to be configured
  2. Configure from server
vim /usr/local/redis/etc/redis.server
slaveof 6379
# Start service
# Or execute the command in redis
slaveof 6379
  • Persistence: persistence is the simplest high availability method (sometimes it is not even classified as a high availability method). Its main function is data backup, that is, data is stored on the hard disk to ensure that data will not be lost due to process exit.
  • Replication: replication is the basis of highly available Redis. Sentinels and clusters achieve high availability on the basis of replication. Replication mainly realizes multi machine backup of data, load balancing for read operation and simple fault recovery. Defect: failure recovery cannot be automated; The write operation cannot be load balanced; The storage capacity is limited by a single machine.
  • Sentry: on the basis of replication, sentry realizes automatic fault recovery. Defect: write operation cannot be load balanced; The storage capacity is limited by a single machine.
  • Cluster: through cluster, Redis solves the problem that the write operation cannot be load balanced and the storage capacity is limited by a single machine, and realizes a relatively perfect high availability scheme.

Keywords: Redis nosql

Added by StormTheGates on Sat, 19 Feb 2022 07:53:43 +0200