NoSQL的引言

NoSQL( Not Only SQL )，意即不仅仅是SQL, 泛指非关系型的数据库。Nosql这个技术门类,早期就有人提出,发展至2009年趋势越发高涨。

RDBMS – 关系型数据库，SQL语句

为什么是NoSQL

随着互联网网站的兴起，传统的关系数据库在应付动态网站，特别是超大规模和高并发的纯动态网站已经显得力不从心，暴露了很多难以克服的问题。如商城网站中对商品数据频繁查询、对热搜商品的排行统计、订单超时问题、以及微信朋友圈（音频，视频）存储等相关使用传统的关系型数据库实现就显得非常复杂，虽然能实现相应功能但是在性能上却不是那么乐观。nosql这个技术门类的出现，更好的解决了这些问题，它告诉了世界不仅仅是sql。

NoSQL四大分类

1. 键值(Key-Value)存储数据库

说明
- 一类数据库主要会使用到一个哈希表，这个表中有一个特定的键和一个指针指向特定的数据。
特点
- Key/value模型对于IT系统来说的优势在于简单、易部署。
- 但是如果DBA只对部分值进行查询或更新的时候，Key/value就显得效率低下了。
相关产品
- Tokyo Cabinet/Tyrant
- Redis – 数据在内存
- SSDB – 数据在硬盘
- Voldemort
- Oracle BDB

2. 列存储数据库

说明
- 这部分数据库通常是用来应对分布式存储的海量数据。
特点
- 键仍然存在，但是它们的特点是指向了多个列。这些列是由列家族来安排的。
相关产品
- Cassandra
- HBase
- Riak

3. 文档型数据库

说明
- 文档型数据库的灵感是来自于Lotus Notes办公软件的，而且它同第一种键值存储相类似该类型的数据模型是版本化的文档，半结构化的文档以特定的格式存储，比如JSON。文档型数据库可以看作是键值数据库的升级版，允许之间嵌套键值。而且文档型数据库比键值数据库的查询效率更高
特点
- 以文档形式存储
相关产品
- MongoDB
- CouchDB
- MongoDb(4.x).
- 国内也有文档型数据库SequoiaDB，已经开源

4. 图形(Graph)数据库

说明
- 图形结构的数据库同其他行列以及刚性结构的SQL数据库不同，它是使用灵活的图形模型，并且能够扩展到多个服务器上。
- NoSQL数据库没有标准的查询语言(SQL)，因此进行数据库查询需要制定数据模型。许多NoSQL数据库都有REST式的数据接口或者查询API。
特点
- NoSQL数据库没有标准的查询语句（SQL），因此进行数据库查询需要定制数据模型。许多NoSQL数据库都有REST式的数据接口或者查询API。
相关产品
- Neo4J
- InfoGrid
- Infinite Graph

NoSQL应用场景

数据模型比较简单
需要灵活性更强的IT系统（系统设计灵活，性能要求比较高）
对数据库性能要求较高
不需要高度的数据一致性（Nosql产品对于事务支持都不是特别良好）

Redis

Redis官方网站：https://redis.io

什么是Redis

Redis is an open source (BSD licensed), in-memory data structure store, used as a database, cache and message broker.

Redis 开源遵循BSD 基于内存数据存储被用于作为数据库缓存消息中间件

Redis 数据存储在内存中，读写快，断电即消失（未进行数据持久化），机制：持久化机制，内存数据，定期写入到磁盘中

总结：redis是一个内存型的数据库
应用：缓存、消息中间件等

Redis特点

Redis是一个高性能key/value内存型数据库
Redis支持丰富的数据类型(String、List、Set、ZSet、Hash)
Redis支持持久化（内存数据持久化到硬盘中）
Redis单线程,单进程（不支持并发，不存在线程安全的问题，Redis实现分布式锁）

Redis安装

准备环境
- CentOS 7.x+
下载redis源码包

拷贝下载连接

Linux系统下，下载完整源码包

[root@localhost ~]# wget https://download.redis.io/releases/redis-6.2.1.tar.gz?_ga=2.236241992.874767586.1616555487-1821064826.1616555487
--2021-03-24 11:24:54--  https://download.redis.io/releases/redis-6.2.1.tar.gz?_ga=2.236241992.874767586.1616555487-1821064826.1616555487
正在解析主机 download.redis.io (download.redis.io)... 45.60.125.1
正在连接 download.redis.io (download.redis.io)|45.60.125.1|:443... 已连接。
已发出 HTTP 请求，正在等待回应... 200 OK
长度：2438367 (2.3M) [application/octet-stream]
正在保存至: “redis-6.2.1.tar.gz?_ga=2.236241992.874767586.1616555487-1821064826.1616555487”

100%[=====================================================================>] 2,438,367   2.02MB/s 用时 1.2s

2021-03-24 11:24:56 (2.02 MB/s) - 已保存 “redis-6.2.1.tar.gz?_ga=2.236241992.874767586.1616555487-1821064826.1616555487” [2438367/2438367])

解压缩文件

[root@localhost ~]# ls
redis-6.2.1.tar.gz?_ga=2.236241992.874767586.1616555487-1821064826.1616555487
[root@localhost ~]# tar -zxvf redis-6.2.1.tar.gz\?_ga\=2.236241992.874767586.1616555487-1821064826.1616555487
redis-6.2.1/
redis-6.2.1/.github/
redis-6.2.1/.github/ISSUE_TEMPLATE/
redis-6.2.1/.github/ISSUE_TEMPLATE/bug_report.md
redis-6.2.1/.github/ISSUE_TEMPLATE/crash_report.md
redis-6.2.1/.github/ISSUE_TEMPLATE/feature_request.md
……
[root@localhost ~]# ls
redis-6.2.1.tar.gz?_ga=2.236241992.874767586.1616555487-1821064826.1616555487
redis-6.2.1

安装gcc

[root@localhost ~]# yum install -y gcc
已加载插件：fastestmirror
Determining fastest mirrors
 * base: mirrors.huaweicloud.com
 * extras: mirrors.huaweicloud.com
 * updates: mirrors.huaweicloud.com
……

进入解压缩目录执行如下命令进行编译

[root@localhost ~]# cd redis-6.2.1
[root@localhost redis-6.2.1]# make MALLOC=libc
cd src && make all
make[1]: 进入目录“/root/redis-6.2.1/src”
    CC Makefile.dep
make[1]: 离开目录“/root/redis-6.2.1/src”
make[1]: 进入目录“/root/redis-6.2.1/src”
rm -rf redis-server redis-sentinel redis-cli redis-benchmark redis-check-rdb redis-check-aof *.o *.gcda *.gcno *.gcov redis.info lcov-html Makefile.dep dict-benchmark
……
    INSTALL redis-check-rdb
    INSTALL redis-check-aof

Hint: It's a good idea to run 'make test' ;)

make[1]: 离开目录“/root/redis-6.2.1/src”

编译完成后执行如下命令

[root@localhost redis-6.2.1]# make install PREFIX=/usr/local/redis
cd src && make install
make[1]: 进入目录“/root/redis-6.2.1/src”
    CC Makefile.dep
make[1]: 离开目录“/root/redis-6.2.1/src”
make[1]: 进入目录“/root/redis-6.2.1/src”

Hint: It's a good idea to run 'make test' ;)

    INSTALL install
    INSTALL install
    INSTALL install
make[1]: 离开目录“/root/redis-6.2.1/src”

进入/usr/local/redis目录启动redis服务

[root@localhost redis-6.2.1]# cd /usr/local/redis/
[root@localhost redis]# ls
bin
[root@localhost redis]# cd bin/
[root@localhost bin]# ls
redis-benchmark  redis-check-aof  redis-check-rdb  redis-cli  redis-sentinel  redis-server
[root@localhost bin]# ./redis-server
5715:C 24 Mar 2021 11:59:45.568 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
5715:C 24 Mar 2021 11:59:45.568 # Redis version=6.2.1, bits=64, commit=00000000, modified=0, pid=5715, just started
5715:C 24 Mar 2021 11:59:45.568 # Warning: no config file specified, using the default config. In order to specify a config file use ./redis-server /path/to/redis.conf
5715:M 24 Mar 2021 11:59:45.570 * Increased maximum number of open files to 10032 (it was originally set to 1024).
5715:M 24 Mar 2021 11:59:45.570 * monotonic clock: POSIX clock_gettime
                _._
           _.-``__ ''-._
      _.-``    `.  `_.  ''-._           Redis 6.2.1 (00000000/0) 64 bit
  .-`` .-```.  ```\/    _.,_ ''-._
 (    '      ,       .-`  | `,    )     Running in standalone mode
 |`-._`-...-` __...-.``-._|'` _.-'|     Port: 6379
 |    `-._   `._    /     _.-'    |     PID: 5715
  `-._    `-._  `-./  _.-'    _.-'
 |`-._`-._    `-.__.-'    _.-'_.-'|
 |    `-._`-._        _.-'_.-'    |           http://redis.io
  `-._    `-._`-.__.-'_.-'    _.-'
 |`-._`-._    `-.__.-'    _.-'_.-'|
 |    `-._`-._        _.-'_.-'    |
  `-._    `-._`-.__.-'_.-'    _.-'
      `-._    `-.__.-'    _.-'
          `-._        _.-'
              `-.__.-'

5715:M 24 Mar 2021 11:59:45.571 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
5715:M 24 Mar 2021 11:59:45.571 # Server initialized
5715:M 24 Mar 2021 11:59:45.571 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
5715:M 24 Mar 2021 11:59:45.572 * Ready to accept connections

启动界面，Redis服务端口默认是 6379

进入bin目录执行客户端连接操作，打开一个新的iTherm，使用客户端连接Redis

[root@localhost ~]# cd /usr/local/redis/
[root@localhost redis]# ls
bin
[root@localhost redis]# cd bin/
[root@localhost bin]# ls
redis-benchmark  redis-check-rdb  redis-sentinel
redis-check-aof  redis-cli        redis-server
[root@localhost bin]# ./redis-cli -h localhost -p 6379
localhost:6379>

连接成功出现上面界面连接成功

Redis配置

redis启动服务的细节
- 注意：直接使用./redis-server方式使用的是redis-server这个shell脚本中默认配置

如何在启动redis时指定配置文件启动

注意：默认在redis安装完成之后再安装目录没有任何配置文件，需要在源码目录中复制redis.conf配置文件到安装目录

[root@localhost redis-6.2.1]# cp redis.conf /usr/local/redis/
[root@localhost redis-6.2.1]# cd /usr/local/redis/
[root@localhost redis]# ls
bin  redis.conf

将配置文件复制到redis目录下后，加载配置启动

[root@localhost redis]# cd bin/
[root@localhost bin]# ./redis-server ../redis.conf
4322:C 25 Mar 2021 12:32:08.516 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
4322:C 25 Mar 2021 12:32:08.516 # Redis version=6.2.1, bits=64, commit=00000000, modified=0, pid=4322, just started
4322:C 25 Mar 2021 12:32:08.516 # Configuration loaded
4322:M 25 Mar 2021 12:32:08.518 * Increased maximum number of open files to 10032 (it was originally set to 1024).
4322:M 25 Mar 2021 12:32:08.518 * monotonic clock: POSIX clock_gettime
                _._
           _.-``__ ''-._
      _.-``    `.  `_.  ''-._           Redis 6.2.1 (00000000/0) 64 bit
  .-`` .-```.  ```\/    _.,_ ''-._
 (    '      ,       .-`  | `,    )     Running in standalone mode
 |`-._`-...-` __...-.``-._|'` _.-'|     Port: 6379
 |    `-._   `._    /     _.-'    |     PID: 4322
  `-._    `-._  `-./  _.-'    _.-'
 |`-._`-._    `-.__.-'    _.-'_.-'|
 |    `-._`-._        _.-'_.-'    |           http://redis.io
  `-._    `-._`-.__.-'_.-'    _.-'
 |`-._`-._    `-.__.-'    _.-'_.-'|
 |    `-._`-._        _.-'_.-'    |
  `-._    `-._`-.__.-'_.-'    _.-'
      `-._    `-.__.-'    _.-'
          `-._        _.-'
              `-.__.-'

4322:M 25 Mar 2021 12:32:08.520 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
4322:M 25 Mar 2021 12:32:08.520 # Server initialized
4322:M 25 Mar 2021 12:32:08.520 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
4322:M 25 Mar 2021 12:32:08.520 * Loading RDB produced by version 6.2.1
4322:M 25 Mar 2021 12:32:08.520 * RDB age 61 seconds
4322:M 25 Mar 2021 12:32:08.520 * RDB memory usage when created 0.84 Mb
4322:M 25 Mar 2021 12:32:08.520 * DB loaded from disk: 0.000 seconds
4322:M 25 Mar 2021 12:32:08.520 * Ready to accept connections

修改配置文件中的配置，例如：默认端口号，再指定配置文件重新启动redis

Redis可视化工具

工具：redis-desktop-manager，该工具收费

官方网站：https://rdm.dev

MacOS

在App Store中搜索，需要人民币98块

注意：远程连接需要开启Redis的远程连接，默认Redis服务器是没有开启远程连接的，也就是默认拒绝所有远程客户端连接

修改配置开启远程连接

1	vim redis.conf

修改如下配置

################################## NETWORK #####################################

# By default, if no "bind" configuration directive is specified, Redis listens
# for connections from all available network interfaces on the host machine.
# It is possible to listen to just one or multiple selected interfaces using
# the "bind" configuration directive, followed by one or more IP addresses.
# Each address can be prefixed by "-", which means that redis will not fail to
# start if the address is not available. Being not available only refers to
# addresses that does not correspond to any network interfece. Addresses that
# are already in use will always fail, and unsupported protocols will always BE
# silently skipped.
#
# Examples:
#
# bind 192.168.1.100 10.0.0.1     # listens on two specific IPv4 addresses
# bind 127.0.0.1 ::1              # listens on loopback IPv4 and IPv6
# bind * -::*                     # like the default, all available interfaces
#
# ~~~ WARNING ~~~ If the computer running Redis is directly exposed to the
# internet, binding to all the interfaces is dangerous and will expose the
# instance to everybody on the internet. So by default we uncomment the
# following bind directive, that will force Redis to listen only on the
# IPv4 and IPv6 (if available) loopback interface addresses (this means Redis
# will only be able to accept client connections from the same host that it is
# running on).
#
# IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES
# JUST COMMENT OUT THE FOLLOWING LINE.
# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# bind 127.0.0.1 -::1
bind 0.0.0.0

将配置文件中的bind 127.0.0.1 -::1修改为bind 0.0.0.0（允许一切客户端连接）

关闭防火墙

查看防火墙状态

[root@localhost ~]# systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
   Active: active (running) since 四 2021-03-25 12:22:30 CST; 4h 39min ago
     Docs: man:firewalld(1)
 Main PID: 2697 (firewalld)
    Tasks: 2
   Memory: 31.3M
   CGroup: /system.slice/firewalld.service
           └─2697 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid

3月 25 12:22:34 localhost.localdomain firewalld[2697]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t ...me.
3月 25 12:22:34 localhost.localdomain firewalld[2697]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t ...?).
3月 25 12:22:34 localhost.localdomain firewalld[2697]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t ...me.
3月 25 12:22:34 localhost.localdomain firewalld[2697]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t ...?).
3月 25 12:22:34 localhost.localdomain firewalld[2697]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t ...me.
3月 25 12:22:34 localhost.localdomain firewalld[2697]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t ...?).
3月 25 12:22:34 localhost.localdomain firewalld[2697]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t ...me.
3月 25 12:22:34 localhost.localdomain firewalld[2697]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t ...me.
3月 25 12:22:34 localhost.localdomain firewalld[2697]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t ...?).
3月 25 12:22:34 localhost.localdomain firewalld[2697]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t ...me.
Hint: Some lines were ellipsized, use -l to show in full.

active (running) :表示防火墙开启