Project leader Knowledge Learning --01- (Redis memory database, Redis, redis five common data types: string / list / hash / set / Zset, Python operations Redis, Redis master-slave configuration)

1, Redis memory database

Background
With the advent of the Internet + big data era, the traditional relational database can no longer large sites in the growing volume of data traffic and meet. This time we need a way to quickly access the component data to ease the pressure on the database server I / O, and to solve the bottleneck on system performance.

History of the development of the database

1. Before the Internet + big data era, some internal corporate information management system, a single database instance will be able to meet the needs of the system
single database instance
2. With the increase of the user's system access, increase in the amount of data, a single instance of the database system has failed to meet the needs of the read
buffer (memcache) + single database instance
3. The read cache can relieve pressure of the system, but the amount of data written to the pressure continues to increase;
buffer + + database read from the main separator
4. The data amount increases again, after the separate read and write, write library pressure of the main bottlenecks database;
cache cluster database from the master + + + sub-library separate read and write sub-table
5. Internet + big data era, relational databases can not access some of the very good high concurrency, high real-time, and the data format is not fixed data. + + NoSQL separate read and write from the main + sub-library database cluster sub-table

2 Redis

Redis is a high-performance, open source, C language development, key nosql database for storing data.

NoSQL: not only sql, refers to non-relational database Redis / MongoDB / Hbase Hadoop
relational databases: MySQL, oracle, SqlServer

Redis properties

When persistence Redis support data, data in memory can be saved to disk, restart can be loaded again using
Redis supports not only simple key-value data types, while also providing List, set data types
Redis supports backup data

Redis what's the use?
The main role of the Redis: Fast access

Redis application scenarios
online buddy list thumbs up / spike / broadcast platform / product ranking / single sign-on

Redis how to use?
Official website address: official website
Command Address: Command Address

Redis five data types and scenarios
string / list / set / hash / zset

Redis installation and startup
in Ubuntu system

sudo apt-get install redis-server

View Help command
redis-server --help

Redis edit the configuration file
sudo vim /etc/redis/redis.conf
will daemonize no change daemonize yes
to save and exit

Start
redis-server

Open the service sudo service redis start

Close service sudo service redis stop

Redis open processes in Windows system : directly extracted, the windows do not support daemonize
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Redis's profile

/etc/redis/redis.conf

When redis run as a daemon, it will write a pid file to /var/run/redis.pid inside.
daemonize no

Listening port number, the default is 6379, if you set to 0, redis will listen to any client is not connected to the socket.
port 6379

Set number of databases.
databases 16

The number of times a given time interval and save the write data to disk
The following example is meant:
if at least one key value change, then stored within 900 seconds
value change key 10 if there are at least 300 seconds, the stored
60 seconds if at least 10,000 key value change, the stored
save 900. 1
save 300 10
save 60 10000

Listening port number, the default is 6379, if you set to 0, redis will listen to any client is not connected to the socket.
port 6379

Redis allows only local connections by default, does not allow other machines connected to
bind 127.0.0.1

More profile: https: //www.cnblogs.com/kreo/p/4423362.html

Simple to use Redis database

DBSIZE ------------------------- view the current key number of databases
keys * ---------------- ----------- view the key content
FLUSHDB --------------------- clear the current number of key database
fLUSHALL ----- --------------- clear all libraries key (caution)
EXISTS Key ----------------------- judge whether there are key

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3, redis five common types of data

1.redis-string

redis string is the most basic type, a key corresponding to a value
string can contain any data, not exceed the maximum 512M

set/get/del/append/strlen

set  ---- 设置值
get  ---- 获取值
mset  ---- 设置多个值
mget  ---- 获取多个值
append ---- 添加字段
del ---- 删除
strlen ---- 返回字符串长度

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incr/decr/incrby/decrby

incr ---- 增加
decr ---- 减少
incrby  ----- 制定增加多少
decrby  ----- 制定减少多少

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getrange / setrange

getrange ---- 获取指定区间范围内的值,类似between....and的关系
setrange ---- 代表从第几位开始替换,下脚本从零开始从0 -1表示全部

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2.redis-list (a single value of the multi value)

List (list)
list is a simple list of strings, insertion order sort, the elements can add a head of the list (left) or a tail portion (right side)
which is a list of the actual underlying

Lpus / Rpus / Lrange

lpush/rpush/lrange ---- 从左/从右/获取指定长度
lpush list01  1 2 3 4 5  倒序排列
rpush list02  1 2 3 4 5  正序排列
lrange  list01  0  -1  获取list01 中的所有值

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lpop/rpop

lpop/rpop ---- 移除最左/最右
lpop list01 删除最左元素
rpop list01 删除最右元素

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lindex, obtained according to the indexing subscript element (top to bottom)

lrange list01 0 -1
lindex list01 1

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llen, seeking list length

llen list01

lrem key

删N个value
lrem list01 2 1   在list01中删除2个1

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ltrim key

ltrim ---- 开始index结束index,截取指定范围的值后在赋值给key
ltrim list01 0 2    截取list01 从0到2的数据在赋值给list01

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rpoplpush list1 list2 to list1 last pushed first in list2

lrange list01 0 -1
lrange list02 0 -1
rpoplpush list1 list2

lset key index value

lset list01 0 x     将list02中第一位换成x

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linsert key before/after

linsert list01b  before x php  在x之前加字段php

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3.redis-Hash

is a collection of hash key
hash is a string type and the value of field mapping table, hash particularly suitable for storing objects

hset/hget/hmset/hmget/hgetall/hdel

设值/取值/设值多个值/取多个值/取全部值/删除值
hset user id 11
hget user id 
hmset customer id 11 name juran age 26
hmget customer id name age      只返回相应的值
hgetall   customer              返回全部
hdel user id   删除id

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hlen seeking hash length

hlen customer

hexists key

hexists ---- 在key里面的某个值
存在返回1 ，不存在返回0

HKEY / whale

hkeys students
hvals students

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4.redis-set (not duplicate)

Set (set)
SET unordered collection of type string, no duplicate elements

Sadd / smembers / sismember

sadd/smembers/sismember ---- 添加/查看集合/查看是否存在
sadd set01 1 2 2 3 3   去掉重复添加
smembers set01         得到set01
sismember set01 1      如果存在返回1  不存在返回0

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scard

scard ---- 获取集合里面的元素个数
scard set01

srem key value

srem ---- 删除集合中元素
srem set01 3
SMEMBERS set01   3已经被删除掉

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srandmember key

srandmembe ---- 随机出几个数
sadd set02  1 2 3 4 5 6 7 8
srandmember set02  2

spop key

spop ---- 随机出栈
spop set01

smove key1 key2

sadd set03 x y z 
smove set01 set03 2  将set01中的2 移动到set03中

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Mathematical collections

sadd set01 1 2 3 4 5
sadd set02 1 2 3 a b
差集
SDIFF set01 set02   返回 4 5 在第一个set中不在第二个set中
交集
SINTER set01 set02   返回 1 2 3
并集
SUNION set01 set02  返回set01 set02 中的值  去掉重复

5.redis-Zset

Zset (ordered set)

zadd/zrange

zadd zset01 60 v1 70 v2 80 v3 90 v4 100 v5
zrange zset01 0 -1 
带分数返回   withscores

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zrangebyscore key start end

zrangebyscore key start end----根据开始结束来取值
zrangebyscore zset01 60 70

zrangebyscore zset01 60 (90   表示不包含90

zrangebyscore zset01  60 90  limit  1 2 从第一条开始截取2条

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zrem key

zrem key value---- 某score下对应的value值,作用是删除元素
zrem zset01 v1

zcard/zcount key score 区间/zrank key values

zcard   求zset01 总条数
zcount  zset01 60 90  求60-90个数
zrank   zset01  v2   返回1  返回对应下角标，从0开始

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4, Python operation Redis

Installation and connection redispy
Installation

pip install redis

connection

r = redis.StrictRedis(host='localhost',port=6379,db=0)

String related operations

import redis


class TestString(object):
    def __init__(self):
        self.r = redis.StrictRedis(host='127.0.0.1', port=6379)
    
    # 设置值
    def string_set(self, keys, items):
        res = self.r.set(keys, items)
        print(res)                              # 返回的是布尔类型的值
    
    # 取值
    def string_get(self, keys):
        res = self.r.get(keys)
        return res
    
    # 设置多个值
    def string_mset(self, items):
        if isinstance(items, dict):
            res = self.r.mset(items)
            print(res)
        
    # 取多个值
    def string_mget(self, keys):
        if isinstance(keys, dict):
            res = self.r.mget(keys)
            print(res)
        
    # 删除
    def string_del(self, keys):
        if self.r.exists(keys):
            self.r.delete(keys)
        else:
            # return "{} is not found".format(keys)
            raise ValueError("{} is not found".format(keys))


if __name__ == '__main__':
    s = TestString()
    
    d = {
        "user": "123",
        "user1": "1"

    }
    s.string_mset(d)
    print(s.string_del("user"))

A list of related operations

import redis


class List_Redis(object):
    def __init__(self):
        self.r = redis.StrictRedis(host='127.0.0.1', port=6379)
    
    # 添加值
    def list_lpush(self, keys, items):
        res = self.r.lpush(keys, items)
        return res
    
    # 删除元素
    def list_lpop(self, keys):
        result = self.r.lpop(keys)
        return result


if __name__ == '__main__':
    l = List_Redis()
    # l.list_lpush('li9', '1 2 3 4 5 6  7 8 8 9')
    l.list_lpop("li9")

A collection of related operations

import redis


class Set_Redis(object):
    def __init__(self):
        self.r = redis.StrictRedis(host='127.0.0.1', port=6379)
        
    # 添加数据
    def set_sadd(self,keys, items):
        result = self.r.sadd(keys, items)
        return result
    
    # 删除数据
    def set_srem(self, keys, values):
        res = self.r.srem(keys, values)
        return res
    
    # 随机删除元素
    def set_pop(self, keys):
        res = self.r.spop(keys)
        return res
    
    
if __name__ == '__main__':
    s = Set_Redis()
    s.set_sadd('s1', '1 2 3 4 5')
    s.set_pop('s1')

Hash-related operations

import redis


class Hash_Redis(object):
    def __init__(self):
        self.r = redis.StrictRedis(host='127.0.0.1', port=6379)

    # 设置值
    def hash_hset(self, keys, items,values):
        result = self.r.hset(keys, items, values)
        return result
    
    # 取值
    def hash_hgetall(self, keys):
        result = self.r.hgetall(keys)
        return result
    
    # 判断是否存在	存在返回1  不存在返回0
    def hash_hexists(self, keys, values):
        res = self.r.hexists(keys, values)
        print(res)
    
    
if __name__ == '__main__':
    h = Hash_Redis()
    h.hash_hset('h1', 'id', '1')

5, Redis master-slave configuration

⼀ a master can have more than one slave, a slave ⼀ separate warranty may have more than one slave, it goes on, forming a strong zoomed multi-level server cluster architecture
master used to write data, slave to read data, the statistics: literacy ratio site is 10: 1
The configuration may be implemented by separate read and write from the primary
master and slave is a redis example (redis service)