首先我们来回顾下代理的概念，所谓代理就是指的是一端面向客户端，另外一端面向服务端，代理客户端访问服务端，我们把这种代理叫正向代理；代理服务端响应客户端我们叫做反向代理，这个我们在之前nginx系列博客中阐述过这样的概念；不管是正向代理还是反向代理他们都是代理，他们都有一个共同点就是代表一端（客户端/服务端）访问或响应另一端；简单讲代理就是即充当服务端角色又充当客户端角色；在mariadb的主从复制集群中，读的能力被扩展了，而写的能力始终没有被扩展；这样一来对于主服务器就存在单点的问题，通常除了做双主可解决主节点单点的问题，我们还可以给主节点做高可用；而对于mariadb的主从复制集群来讲，虽然读的能力提升了，但通常情况后端数据库服务器是直接面向程序，这意味着程序要知道读请求和写请求该发往不同的数据库服务器上；在用户发来读请求，这个程序它会分析用户的请求，然后把用户的请求代理到后端server上；也就是说我们需要一个程序能够解析用户的读写操作，把对应的操作代理到后端不同的节点上；这样一来用户的读操作始终均衡的被调度到从节点，写操作调度到主节点；proxysql这款软件就有我们上面说的功能，它能够将用户发来的读写操作，通过proxysql的语句路由，把对应请求分别发送到不同节点执行；如下图所示：
从上面的图片可以看到，proxysql就是一代理，面向程序它就是一数据库服务器，程序把读操作和写操作都发送给它，然后proxysql通过我们定义的路由规则，把对应语句再代理到不同的后端主从架构节点上执行；接下来我们来看看proxysql的配置和使用吧；以下实验室基于mariadb的主从复制集群上做的，有关主从复制的配置请参考https://www.cnblogs.com/qiuhom-1874/tag/mariadb%E4%B8%BB%E4%BB%8E%E5%A4%8D%E5%88%B6/；
1、安装proxysql(添加yum源，直接用yum安装)
2、查看proxysql的简介
[root@lxc ~]# yum info proxysql
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: mirrors.aliyun.com
* extras: mirrors.aliyun.com
* updates: mirrors.aliyun.com
Available Packages
Name : proxysql
Arch : x86_64
Version : 2.0.12
Release : 1
Size : 9.8 M
Repo : proxysql_repo/7
Summary : A high-performance MySQL proxy
URL : https://proxysql.com/
License : GPL+
Description : A high-performance MySQL proxy
[root@lxc ~]#提示：如果添加了yum直接yum info proxysql能够看到以上信息，表示我们添加到yum源已经生效；
3、安装proxysql
[root@lxc ~]# yum install proxysql
Loaded plugins: fastestmirror
proxysql_repo | 2.9 kB 00:00:00
Loading mirror speeds from cached hostfile
* base: mirrors.aliyun.com
* extras: mirrors.aliyun.com
* updates: mirrors.aliyun.com
Resolving Dependencies
--> Running transaction check
---> Package proxysql.x86_64 0:2.0.12-1 will be installed
--> Processing Dependency: libgnutls.so.28(GNUTLS_3_1_0)(64bit) for package: proxysql-2.0.12-1.x86_64
--> Processing Dependency: libgnutls.so.28(GNUTLS_3_0_0)(64bit) for package: proxysql-2.0.12-1.x86_64
--> Processing Dependency: gnutls for package: proxysql-2.0.12-1.x86_64
--> Processing Dependency: libgnutls.so.28(GNUTLS_1_4)(64bit) for package: proxysql-2.0.12-1.x86_64
--> Processing Dependency: libgnutls.so.28()(64bit) for package: proxysql-2.0.12-1.x86_64
--> Running transaction check
---> Package gnutls.x86_64 0:3.3.29-9.el7_6 will be installed
--> Processing Dependency: trousers >= 0.3.11.2 for package: gnutls-3.3.29-9.el7_6.x86_64
--> Processing Dependency: libnettle.so.4()(64bit) for package: gnutls-3.3.29-9.el7_6.x86_64
--> Processing Dependency: libhogweed.so.2()(64bit) for package: gnutls-3.3.29-9.el7_6.x86_64
--> Running transaction check
---> Package nettle.x86_64 0:2.7.1-8.el7 will be installed
---> Package trousers.x86_64 0:0.3.14-2.el7 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
=====================================================================================================================================================================
Package Arch Version Repository Size
=====================================================================================================================================================================
Installing:
proxysql x86_64 2.0.12-1 proxysql_repo 9.8 M
Installing for dependencies:
gnutls x86_64 3.3.29-9.el7_6 base 680 k
nettle x86_64 2.7.1-8.el7 base 327 k
trousers x86_64 0.3.14-2.el7 base 289 k
Transaction Summary
=====================================================================================================================================================================
Install 1 Package (+3 Dependent packages)
Total download size: 11 M
Installed size: 41 M
Is this ok [y/d/N]: y
Downloading packages:
(1/4): gnutls-3.3.29-9.el7_6.x86_64.rpm | 680 kB 00:00:00
(2/4): nettle-2.7.1-8.el7.x86_64.rpm | 327 kB 00:00:00
(3/4): trousers-0.3.14-2.el7.x86_64.rpm | 289 kB 00:00:00
warning: /var/cache/yum/x86_64/7/proxysql_repo/packages/proxysql-2.0.12-1-centos7.x86_64.rpm: Header V4 RSA/SHA256 Signature, key ID 79953b49: NOKEYMB 00:00:04 ETA
Public key for proxysql-2.0.12-1-centos7.x86_64.rpm is not installed
(4/4): proxysql-2.0.12-1-centos7.x86_64.rpm | 9.8 MB 00:28:05
---------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total 6.7 kB/s | 11 MB 00:28:05
Retrieving key from https://repo.proxysql.com/ProxySQL/repo_pub_key
Importing GPG key 0x79953B49:
Userid : "rene cannnao (Proxysql Repository) <rene.cannao@gmail.com>"
Fingerprint: 1448 bf69 3ca6 00c7 99eb 9358 04a5 62fb 7995 3b49
From : https://repo.proxysql.com/ProxySQL/repo_pub_key
Is this ok [y/N]: y
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : trousers-0.3.14-2.el7.x86_64 1/4
Installing : nettle-2.7.1-8.el7.x86_64 2/4
Installing : gnutls-3.3.29-9.el7_6.x86_64 3/4
Installing : proxysql-2.0.12-1.x86_64 4/4
warning: group proxysql does not exist - using root
warning: group proxysql does not exist - using root
Created symlink from /etc/systemd/system/multi-user.target.wants/proxysql.service to /etc/systemd/system/proxysql.service.
Verifying : gnutls-3.3.29-9.el7_6.x86_64 1/4
Verifying : proxysql-2.0.12-1.x86_64 2/4
Verifying : nettle-2.7.1-8.el7.x86_64 3/4
Verifying : trousers-0.3.14-2.el7.x86_64 4/4
Installed:
proxysql.x86_64 0:2.0.12-1
Dependency Installed:
gnutls.x86_64 0:3.3.29-9.el7_6 nettle.x86_64 0:2.7.1-8.el7 trousers.x86_64 0:0.3.14-2.el7
Complete!
[root@lxc ~]#提示：除此以上方式安装proxysql，当然也可以直接使用wget 去github上的项目地址下载
[root@lxc ~]# wget https://github.com/sysown/proxysql/releases/download/v2.0.12/proxysql-2.0.12-1-centos7.x86_64.rpm提示：下载好proxysql 包后，然后通过yum直接安装即可；推荐使用yum来安装下载好的包，它可以解决依赖关系，不推荐使用rpm 安装；
4、查看proxysql包安装的文件列表
[root@lxc ~]# rpm -ql proxysql
/etc/logrotate.d/proxysql
/etc/proxysql.cnf
/etc/systemd/system/proxysql-initial.service
/etc/systemd/system/proxysql.service
/usr/bin/proxysql
/usr/share/proxysql/tools/proxysql_galera_checker.sh
/usr/share/proxysql/tools/proxysql_galera_writer.pl
[root@lxc ~]#提示：从上面的信息可以看到proxysql的配置文件是/etc/proxysql.cnf,二进制文件是/usr/bin/proxysql，unit file是/etc/systemd/system/proxysql.service
5、配置proxysql
[root@lxc ~]# cat /etc/proxysql.cnf
########################################################################################
datadir="/var/lib/proxysql"
errorlog="/var/lib/proxysql/proxysql.log"
admin_variables=
{
admin_credentials="admin:admin"
# mysql_ifaces="127.0.0.1:6032;/tmp/proxysql_admin.sock"
mysql_ifaces="0.0.0.0:6033"
# refresh_interval=2000
# debug=true
}
mysql_variables=
{
threads=4
max_connections=2048
default_query_delay=0
default_query_timeout=36000000
have_compress=true
poll_timeout=2000
# interfaces="0.0.0.0:6033;/tmp/proxysql.sock"
interfaces="0.0.0.0:3306"
default_schema="information_schema"
stacksize=1048576
server_version="5.5.30"
connect_timeout_server=3000
# make sure to configure monitor username and password
# https://github.com/sysown/proxysql/wiki/Global-variables#mysql-monitor_username-mysql-monitor_password
monitor_username="monitor"
monitor_password="monitor"
monitor_history=600000
monitor_connect_interval=60000
monitor_ping_interval=10000
monitor_read_only_interval=1500
monitor_read_only_timeout=500
ping_interval_server_msec=120000
ping_timeout_server=500
commands_stats=true
sessions_sort=true
connect_retries_on_failure=10
}
# defines all the MySQL servers
mysql_servers =
(
{
address = "192.168.0.22" # no default, required . If port is 0 , address is interpred as a Unix Socket Domain
port = 3306 # no default, required . If port is 0 , address is interpred as a Unix Socket Domain
hostgroup = 3 # no default, required
status = "ONLINE" # default: ONLINE
weight = 1 # default: 1
compression = 0 # default: 0
max_replication_lag = 10 # default 0 . If greater than 0 and replication lag passes such threshold, the server is shunned
},
{
address = "192.168.0.23" # no default, required . If port is 0 , address is interpred as a Unix Socket Domain
port = 3306 # no default, required . If port is 0 , address is interpred as a Unix Socket Domain
hostgroup = 4 # no default, required
status = "ONLINE" # default: ONLINE
weight = 1 # default: 1
compression = 0 # default: 0
max_replication_lag = 10 # default 0 . If greater than 0 and replication lag passes such threshold, the server is shunned
}
)
# defines all the MySQL users
mysql_users:
(
{
username = "root" # no default , required
password = "admin123.com" # default: ''
default_hostgroup = 3 # default: 0
active = 1 # default: 1
}
)
#defines MySQL Query Rules
mysql_query_rules:
(
{
rule_id=1
active=1
match_pattern="^SELECT .* FOR UPDATE$"
destination_hostgroup=3
apply=1
},
{
rule_id=2
active=1
match_pattern="^SELECT"
destination_hostgroup=4
apply=1
}
)
mysql_replication_hostgroups=
(
{
writer_hostgroup=3
reader_hostgroup=4
comment="test repl 1"
}
)
[root@lxc ~]#提示：proxysql配置文件分几个大段，admin_variables这个段里主要配置管理相关变量，比如管理用户名和密码，监听的地址和端口等等；mysql_variables配置proxysql连接后端mysql相关配置，里面有连接后端的server监听的端口，线程数，最大连接数，以及监控相关参数；mysql_servers配置后端mysql/mariadb服务器的地址端口，以及权重，所属组等；mysql_users配置连接后端mysql/mariadb所需的账号和密码以及默认连接到的组；mysql_query_rules配置查询规则，那些语句是写操作，那些语句是读操作；mysql_replication_hostgroups配置写操作对应的组号和读操作对应组号；这里需要注意一点，如果一个配置段中有多个大括号，相互之间用逗号隔离，如果是最后一个大括号需要把后面的逗号去掉；
6、在主从复制节点创建上面配置的账号信息
创建root账号
[root@docker_node01 ~]# mysql
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 9
Server version: 5.5.65-MariaDB MariaDB Server
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MariaDB [(none)]> select user,host,password from mysql.user;
+---------+-------------------+-------------------------------------------+
| user | host | password |
+---------+-------------------+-------------------------------------------+
| root | localhost | |
| root | docker\_node01.io | |
| root | 127.0.0.1 | |
| root | ::1 | |
| rpluser | 192.168.0.% | *4ACFE3202A5FF5CF467898FC58AAB1D615029441 |
+---------+-------------------+-------------------------------------------+
5 rows in set (0.00 sec)
MariaDB [(none)]> grant all on *.* to 'root'@'192.168.0.%' identified by 'admin123.com' with grant option;
Query OK, 0 rows affected (0.01 sec)
MariaDB [(none)]> select user,host,password from mysql.user;
+---------+-------------------+-------------------------------------------+
| user | host | password |
+---------+-------------------+-------------------------------------------+
| root | localhost | |
| root | docker\_node01.io | |
| root | 127.0.0.1 | |
| root | ::1 | |
| rpluser | 192.168.0.% | *4ACFE3202A5FF5CF467898FC58AAB1D615029441 |
| root | 192.168.0.% | *2D9AC2437F9E59A51BE8BA89A3D59E76F32F55E8 |
+---------+-------------------+-------------------------------------------+
6 rows in set (0.00 sec)
MariaDB [(none)]>提示：在主节点创建账号会自动同步到从节点，所以从节点可以不用再创建；
创建monitor账号
MariaDB [(none)]> grant all on *.* to 'monitor'@'192.168.0.%' identified by 'monitor' with grant option;
Query OK, 0 rows affected (0.01 sec)
MariaDB [(none)]> select user,host,password from mysql.user;
+---------+-------------------+-------------------------------------------+
| user | host | password |
+---------+-------------------+-------------------------------------------+
| root | localhost | |
| root | docker\_node01.io | |
| root | 127.0.0.1 | |
| root | ::1 | |
| rpluser | 192.168.0.% | *4ACFE3202A5FF5CF467898FC58AAB1D615029441 |
| root | 192.168.0.% | *2D9AC2437F9E59A51BE8BA89A3D59E76F32F55E8 |
| monitor | 192.168.0.% | *1975D095AC033CAF4E1BF94F7202A9BBFEEB66F1 |
+---------+-------------------+-------------------------------------------+
7 rows in set (0.00 sec)
MariaDB [(none)]>7、启动proxysql
提示：可以看到我们配置的proxysql管理端监听在6033，启动4个线程来连接后端mariadb服务器，对应的端口都已经处于监听状态了；
8、连接管理端口
[root@lxc ~]# mysql -uadmin -padmin -h192.168.0.21 -P6033
ERROR 1040 (42000): User 'admin' can only connect locally
[root@lxc ~]# mysql -uadmin -padmin -h127.0.0.1 -P6033
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 5.5.30 (ProxySQL Admin Module)
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MySQL [(none)]> show databases;
+-----+---------------+-------------------------------------+
| seq | name | file |
+-----+---------------+-------------------------------------+
| 0 | main | |
| 2 | disk | /var/lib/proxysql/proxysql.db |
| 3 | stats | |
| 4 | monitor | |
| 5 | stats_history | /var/lib/proxysql/proxysql_stats.db |
+-----+---------------+-------------------------------------+
5 rows in set (0.001 sec)
MySQL [(none)]>提示：管理接口默认只能本地连接，但是我们配置管理接口监听在本机所有地址上，所以连接时指定主机地址要使用127.0.0.1才可以，如果使用localhost，它默认会通过sock文件去连接；从上面的结果可以看到，在proxysql上有5个库，其中main库主要存放我们刚才配置相关的表在里面；如下
MySQL [(none)]> use main
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
MySQL [main]> show tables;
+----------------------------------------------------+
| tables |
+----------------------------------------------------+
| global_variables |
| mysql_aws_aurora_hostgroups |
| mysql_collations |
| mysql_firewall_whitelist_rules |
| mysql_firewall_whitelist_sqli_fingerprints |
| mysql_firewall_whitelist_users |
| mysql_galera_hostgroups |
| mysql_group_replication_hostgroups |
| mysql_query_rules |
| mysql_query_rules_fast_routing |
| mysql_replication_hostgroups |
| mysql_servers |
| mysql_users |
| proxysql_servers |
| restapi_routes |
| runtime_checksums_values |
| runtime_global_variables |
| runtime_mysql_aws_aurora_hostgroups |
| runtime_mysql_firewall_whitelist_rules |
| runtime_mysql_firewall_whitelist_sqli_fingerprints |
| runtime_mysql_firewall_whitelist_users |
| runtime_mysql_galera_hostgroups |
| runtime_mysql_group_replication_hostgroups |
| runtime_mysql_query_rules |
| runtime_mysql_query_rules_fast_routing |
| runtime_mysql_replication_hostgroups |
| runtime_mysql_servers |
| runtime_mysql_users |
| runtime_proxysql_servers |
| runtime_restapi_routes |
| runtime_scheduler |
| scheduler |
+----------------------------------------------------+
32 rows in set (0.001 sec)
MySQL [main]> select * from mysql_servers;
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| 3 | 192.168.0.22 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | |
| 4 | 192.168.0.23 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
2 rows in set (0.001 sec)
MySQL [main]>提示：main库中的表以runtime开头的表示当前生效的配置，如果我们要运行时修改配置，我们需要先修改不是runtime开头的表，然后通过load 加载到runtime开头的表中，然后在save存储到文件；
proxysql的多层配置系统
+-------------------------+
| RUNTIME |
+-------------------------+
/|\ |
| |
[1] | [2] |
| \|/
+-------------------------+
| MEMORY |
+-------------------------+ _
/|\ | |\
| | \
[3] | [4] | \ [5]
| \|/ \
+-------------------------+ +-------------------------+
| DISK | | CONFIG FILE |
+-------------------------+ +-------------------------+提示：从上面的图可以看到proxysql的配置系统分三层，最上面一层是runtime层，该层主要是说通过读取第二层的memory层，而memory主要通过disk或configfile层来获取配置；第一次启动proxysql时，它会从config file层读取配置文件内容到memory层，然后runtime层读取memory层，随后我们就可以通过修改memory层，然后通过load加载到runtime层，或者save存储到disk层；
在各层间移动配置
MySQL user相关操作：
LOAD MYSQL USERS FROM MEMORY / LOAD MYSQL USERS TO RUNTIME
将MySQL user从内存数据库加载到运行时数据结构，反之亦然
SAVE MYSQL USERS TO MEMORY / SAVE MYSQL USERS FROM RUNTIME
将MySQL user从运行时持久化到内存数据库
LOAD MYSQL USERS TO MEMORY / LOAD MYSQL USERS FROM DISK
将持久化的MySQL user从磁盘数据库加载到内存数据库
SAVE MYSQL USERS FROM MEMORY / SAVE MYSQL USERS TO DISK
将MySQL user从内存数据库持久化到磁盘数据库
LOAD MYSQL USERS FROM CONFIG
从配置文件中将MySQL user加载到内存数据库中
MySQL server相关操作：
LOAD MYSQL SERVERS FROM MEMORY / LOAD MYSQL SERVERS TO RUNTIME
将MySQL server从内存数据库加载到运行时
SAVE MYSQL SERVERS TO MEMORY / SAVE MYSQL SERVERS FROM RUNTIME
将MySQL server从运行时持久化到内存数据库
LOAD MYSQL SERVERS TO MEMORY / LOAD MYSQL SERVERS FROM DISK
将MySQL server从磁盘数据库加载到内存数据库
SAVE MYSQL SERVERS FROM MEMORY / SAVE MYSQL SERVERS TO DISK
将MySQL server从内存数据库持久化到磁盘数据库
LOAD MYSQL SERVERS FROM CONFIG
从配置文件将服务器加载到内存数据库中
MySQL query rules相关操作：
LOAD MYSQL QUERY RULES FROM MEMORY / LOAD MYSQL QUERY RULES TO RUNTIME
将MySQL查询规则从内存数据库加载到运行时数据结构
SAVE MYSQL QUERY RULES TO MEMORY / SAVE MYSQL QUERY RULES FROM RUNTIME
将MySQL查询规则从运行时数据结构持久化到内存数据库
LOAD MYSQL QUERY RULES TO MEMORY / LOAD MYSQL QUERY RULES FROM DISK
将MySQL查询规则从磁盘数据库加载到内存数据库
SAVE MYSQL QUERY RULES FROM MEMORY / SAVE MYSQL QUERY RULES TO DISK
将MySQL查询规则从内存数据库持久化到磁盘数据库
LOAD MYSQL QUERY RULES FROM CONFIG
从配置文件查询规则加载到内存数据库中
MySQL variables相关操作：
LOAD MYSQL VARIABLES FROM MEMORY / LOAD MYSQL VARIABLES TO RUNTIME
将MySQL变量从内存数据库加载到运行时数据结构
SAVE MYSQL VARIABLES FROM MEMORY / SAVE MYSQL VARIABLES TO DISK
将MySQL变量从内存数据库持久化到磁盘数据库
LOAD MYSQL VARIABLES TO MEMORY / LOAD MYSQL VARIABLES FROM DISK
将MySQL变量从磁盘数据库加载到内存数据库
SAVE MYSQL VARIABLES TO MEMORY / SAVE MYSQL VARIABLES FROM RUNTIME
将MySQL变量从运行时数据结构持久存储到内存数据库中
LOAD MYSQL VARIABLES FROM CONFIG
将配置文件变量加载到内存数据库中
admin variables相关操作：
LOAD ADMIN VARIABLES FROM MEMORY / LOAD ADMIN VARIABLES TO RUNTIME
将内存数据库中的管理变量加载到运行时
SAVE ADMIN VARIABLES TO MEMORY / SAVE ADMIN VARIABLES FROM RUNTIME
将管理变量从运行时持久化到内存数据库
LOAD ADMIN VARIABLES TO MEMORY / LOAD ADMIN VARIABLES FROM DISK
将管理变量从磁盘数据库加载到内存数据库
SAVE ADMIN VARIABLES FROM MEMORY / SAVE ADMIN VARIABLES TO DISK
将管理变量从内存数据库持久化到磁盘数据库
LOAD ADMIN VARIABLES FROM CONFIG
将配置文件管理变量加载到内存数据库中
注意：以上命令允许使用以下快捷方式：
MEM for MEMORY
RUN for RUNTIME
例如，这两个命令是等效的：
SAVE ADMIN VARIABLES TO MEMORY
SAVE ADMIN VARIABLES TO MEM提示：以上命令在配置更改加载到RUNTIME之前不会激活任何修改，也就是说只有runtime中的配置生效；
测试：在线增加后端mysql server的地址
[root@lxc ~]# mysql -uadmin -padmin -h127.0.0.1 -P6033
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.5.30 (ProxySQL Admin Module)
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MySQL [(none)]> select * from mysql_servers;
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| 3 | 192.168.0.22 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | |
| 4 | 192.168.0.23 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
2 rows in set (0.001 sec)
MySQL [(none)]> insert into mysql_servers values (4,'192.168.0.21',3307,0,'ONLINE',1,0,1000,10,0,0,'');
Query OK, 1 row affected (0.001 sec)
MySQL [(none)]> select * from mysql_servers;
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| 3 | 192.168.0.22 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | |
| 4 | 192.168.0.23 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | |
| 4 | 192.168.0.21 | 3307 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
3 rows in set (0.001 sec)
MySQL [(none)]>提示：以上操作只在memory层中修改，并未加载到runtime，所以在runtime_mysql_servers表中还是两台后端server
加载mysql server memory层到runtime层
MySQL [(none)]> show tables;
+----------------------------------------------------+
| tables |
+----------------------------------------------------+
| global_variables |
| mysql_aws_aurora_hostgroups |
| mysql_collations |
| mysql_firewall_whitelist_rules |
| mysql_firewall_whitelist_sqli_fingerprints |
| mysql_firewall_whitelist_users |
| mysql_galera_hostgroups |
| mysql_group_replication_hostgroups |
| mysql_query_rules |
| mysql_query_rules_fast_routing |
| mysql_replication_hostgroups |
| mysql_servers |
| mysql_users |
| proxysql_servers |
| restapi_routes |
| runtime_checksums_values |
| runtime_global_variables |
| runtime_mysql_aws_aurora_hostgroups |
| runtime_mysql_firewall_whitelist_rules |
| runtime_mysql_firewall_whitelist_sqli_fingerprints |
| runtime_mysql_firewall_whitelist_users |
| runtime_mysql_galera_hostgroups |
| runtime_mysql_group_replication_hostgroups |
| runtime_mysql_query_rules |
| runtime_mysql_query_rules_fast_routing |
| runtime_mysql_replication_hostgroups |
| runtime_mysql_servers |
| runtime_mysql_users |
| runtime_proxysql_servers |
| runtime_restapi_routes |
| runtime_scheduler |
| scheduler |
+----------------------------------------------------+
32 rows in set (0.001 sec)
MySQL [(none)]> select * from runtime_mysql_servers;
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| 3 | 192.168.0.22 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | |
| 4 | 192.168.0.23 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
2 rows in set (0.006 sec)
MySQL [(none)]> select * from mysql_servers;
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| 3 | 192.168.0.22 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | |
| 4 | 192.168.0.23 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | |
| 4 | 192.168.0.21 | 3307 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
3 rows in set (0.001 sec)
MySQL [(none)]> load mysql servers to runtime;
Query OK, 0 rows affected (0.015 sec)
MySQL [(none)]> select * from runtime_mysql_servers;
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| 3 | 192.168.0.22 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | |
| 4 | 192.168.0.21 | 3307 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | |
| 4 | 192.168.0.23 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
3 rows in set (0.006 sec)
MySQL [(none)]>提示：可以看到执行load操作后，runtime_mysql_servers就加载进去了；此时我们就把memory层的信息加载到runtime层生效了；
验证：通过连接proxysql所在主机的3306端口，执行写操作，看看是否能够同步到其他从节点？
提示：可以看到在proxysql所在主机连接3306线程，是可以连接到主库，因为默认配置连接是到主库，然后在其上创建一个mydb的数据库，也能够及时的同步到其他从库；
测试：读写操作是否分别调度到不同的节点上？
[root@lxc ~]# for i in {1..10} ;do mysql -uroot -padmin123.com -P3306 -h192.168.0.21 -e "select @@server_id" ; done
+-------------+
| @@server_id |
+-------------+
| 2 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 2 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 2 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 3 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 3 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 3 |
+-------------+
[root@lxc ~]# for i in {1..10} ;do mysql -uroot -padmin123.com -P3306 -h192.168.0.21 -e "select @@server_id for update" ; done
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
[root@lxc ~]#提示：可以看到当执行有写锁时，就立刻把操作调度到server_id=1的主库上去操作；读操作是随机调度到各个节点上进行处理；
来源：oschina
链接：https://my.oschina.net/u/4283198/blog/4365680