proxysql配置mysql读写分离
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2022-05-02 10:05:24
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1. 不同类型的读写分离方案解析
数据库中间件最基本的功能就是实现读写分离， ProxySQL 当然也支持。而且 ProxySQL 支持的路由规则非常灵活，不仅可以实现最简单的读写分离，还可以将读/写都分散到多个不同的组，以及实现分库 sharding (分表sharding的规则比较难写，但也能实现)。
本文只描述通过规则制定的语句级读写分离，不讨论通过 ip/port, client, username, schemaname 实现的读写分离。
下面描述了ProxySQL能实现的常见读写分离类型
1.1 最简单的读写分离
这种模式的读写分离，严格区分后端的master和slave节点，且slave节点必须设置选项read_only=1
在ProxySQL上，分两个组，一个写组HG=10，一个读组HG=20。同时在ProxySQL上开启monitor模块的read_only监控功能，让ProxySQL根据监控到的read_only值来自动调整节点放在HG=10(master会放进这个组)还是HG=20(slave会放进这个组)
这种模式的读写分离是最简单的，只需在mysql_users表中设置用户的默认路由组为写组HG=10，并在mysql_query_rules中加上两条简单的规则(一个select for update，一个select)即可
这种读写分离模式，在环境较小时能满足绝大多数需求。但是需求复杂、环境较大时，这种模式就太过死板，因为一切都是monitor模块控制的
1.2 多个读组或写组的分离模式
前面那种读写分离模式，是通过 monitor 模块监控 read_only 来调整的，所以每一个后端集群必须只能分为一个写组，一个读组。
但如果想要区分不同的 select ，并将不同的 select 路由到不同的节点上。例如有些查询语句的开销非常大，想让它们独占一个节点/组，其它查询共享一个节点/组，怎么实现？
例如，下面这种模式
看上去非常简单。但是却能适应各种需求。例如，后端做了分库，对某库的查询要路由到特定的主机组
至于各个主机组是同一个主从集群(下图左边)，还是互相独立的主从集群环境(下图右边)，要看具体的需求，不过这种读写分离模式都能应付
在实现这种模式时，前提是不能开启monitor模块的read_only监控功能，也不要设置mysql_replication_hostgroup 表
例如，下面的配置实现的是上图左边的结构：写请求路由给HG=10，对test1库的select语句路由给HG=20，其它select路由给HG=30
mysql_servers:
+--------------+----------+------+--------+--------+
| hostgroup_id | hostname | port | status | weight |
+--------------+----------+------+--------+--------+
| 10 | host1 | 3306 | ONLINE | 1 |
| 20 | host2 | 3306 | ONLINE | 1 |
| 30 | host3 | 3306 | ONLINE | 1 |
+--------------+----------+------+--------+--------+
mysql_users:
+----------+-------------------+
| username | default_hostgroup |
+----------+-------------------+
| root | 10 |
+----------+-------------------+
mysql_query_rules:
+---------+-----------------------+----------------------+
| rule_id | destination_hostgroup | match_digest |
+---------+-----------------------+----------------------+
| 1 | 10 | ^SELECT.*FOR UPDATE$ |
| 2 | 20 | ^SELECT.*test1\..* |
| 3 | 30 | ^SELECT |
+---------+-----------------------+----------------------+
查看表结构的方式：
PRAGMA table_info("表名");
2. ProxySQL实现读写分离示例
环境说明：
| IP | 角色 | 所需服务 |
|---|---|---|
| 192.168.159.136 | 读写分离解析主机 | proxysql |
| 192.168.159.137 | master | mysql或者mariadb |
| 192.168.159.144 | slave | mysql或者mariadb |
在做实验前，需要：
- 关闭防火墙和SELINUX
- 安装mysql并配置主从
2.1 安装ProxySQL
//下载proxysql的安装包，并安装
[aaa@qq.com ~]# wget http://repo.proxysql.com/ProxySQL/proxysql-2.0.x/centos/7/proxysql-2.0.13-1-centos7.x86_64.rpm
[aaa@qq.com ~]# ls
anaconda-ks.cfg proxysql-2.0.13-1-centos7.x86_64.rpm
[aaa@qq.com ~]# yum -y localinstall proxysql-2.0.13-1-centos7.x86_64.rpm
//启动proxysql并设置开机自动启动
[aaa@qq.com ~]# systemctl start proxysql
[aaa@qq.com ~]# chkconfig proxysql on
[aaa@qq.com ~]# ss -anlt
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 *:6032 *:*
LISTEN 0 128 *:6033 *:*
LISTEN 0 128 *:6033 *:*
LISTEN 0 128 *:6033 *:*
LISTEN 0 128 *:6033 *:*
LISTEN 0 128 *:22 *:*
LISTEN 0 100 127.0.0.1:25 *:*
LISTEN 0 128 :::22 :::*
LISTEN 0 100 ::1:25 :::*
//下载mariadb（客户端就行）
[aaa@qq.com ~]# yum -y install mariadb
//登录proxysql
[aaa@qq.com ~]# mysql -uadmin -padmin -h127.0.0.1 -P6032
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MySQL connection id is 1
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 (0.00 sec)
2.2 配置主从
主上的操作
//配置网络源
[aaa@qq.com yum.repos.d]# ls
CentOS-Base.repo epel.repo
//安装mariadb
[aaa@qq.com ~]# yum -y install mariadb*
............
//启动服务
[aaa@qq.com ~]# systemctl enable --now mariadb
Created symlink from /etc/systemd/system/multi-user.target.wants/mariadb.service to /usr/lib/systemd/system/mariadb.service.
[aaa@qq.com ~]# ss -anlt
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 50 *:3306 *:*
LISTEN 0 128 *:22 *:*
LISTEN 0 100 127.0.0.1:25 *:*
LISTEN 0 128 :::22 :::*
LISTEN 0 100 ::1:25 :::*
//创建一个同步账号授权给从数据库使用
[aaa@qq.com ~]# mysql
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 2
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)]> grant replication slave on *.* to 'repl'@'192.168.159.144' identified by 'repl123.';
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> flush privileges;
Query OK, 0 rows affected (0.00 sec)
//修改配置文件
[aaa@qq.com ~]# vim /etc/my.cnf
............
//添加以下内容
server-id=10
log-bin=mysql-bin
//重启服务
[aaa@qq.com ~]# systemctl restart mariadb
[aaa@qq.com ~]# ss -anlt
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 50 *:3306 *:*
LISTEN 0 128 *:22 *:*
LISTEN 0 100 127.0.0.1:25 *:*
LISTEN 0 128 :::22 :::*
LISTEN 0 100 ::1:25 :::*
//查看主库的状态
[aaa@qq.com ~]# mysql
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 3
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)]> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000001 | 245 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
备上的操作
//配置网络源
[aaa@qq.com ~]# ls /etc/yum.repos.d/
CentOS-Base.repo epel.repo
//安装mariadb
[aaa@qq.com ~]# yum -y install mariadb*
............
//修改配置文件
[aaa@qq.com ~]# vim /etc/my.cnf
............
//添加以下内容
server-id=20
relay-log=mysql-relay-bin
//重启服务
[aaa@qq.com ~]# systemctl restart mariadb
[aaa@qq.com ~]# ss -anlt
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 50 *:3306 *:*
LISTEN 0 128 *:22 *:*
LISTEN 0 100 127.0.0.1:25 *:*
LISTEN 0 128 :::22 :::*
LISTEN 0 100 ::1:25 :::*
//查看并启动主从复制
[aaa@qq.com ~]# mysql
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 3
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)]> change master to master_host='192.168.159.137',master_user='repl',master_password='repl123.',master_log_file='mysql-bin.000001',master_log_pos=245;
Query OK, 0 rows affected (0.03 sec)
MariaDB [(none)]> start slave;
Query OK, 0 rows affected (0.00 sec)
//查看从服务器状态
MariaDB [(none)]> show slave status \G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.159.137
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000001
Read_Master_Log_Pos: 245
Relay_Log_File: mysql-relay-bin.000002
Relay_Log_Pos: 529
Relay_Master_Log_File: mysql-bin.000001
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 245
Relay_Log_Space: 823
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 10
1 row in set (0.00 sec)
测试验证有没有完成主从同步
//在从上创建个库
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| test |
+--------------------+
4 rows in set (0.00 sec)
MariaDB [(none)]> create database school;
Query OK, 1 row affected (0.00 sec)
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| school |
| test |
+--------------------+
5 rows in set (0.00 sec)
//在备上查看
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| school |
| test |
+--------------------+
5 rows in set (0.00 sec)
//成功配置好了主从
2.3 配置proxysql
2.3.1 mysql主库添加proxysql可以增删改查的账号
MariaDB [(none)]> grant all on *.* to 'proxysql'@'192.168.159.136' identified by 'aaa@qq.com';
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> flush privileges;
Query OK, 0 rows affected (0.00 sec)
2.3.2 添加 mysql 主机到 mysql_servers 表中
hostgroup_id 10表示写组，20表示读组
MySQL [(none)]> insert into mysql_servers(hostgroup_id,hostname,port,weight,comment) values(10,'192.168.159.137',3306,1,'Write Group');
Query OK, 1 row affected (0.00 sec)
MySQL [(none)]> insert into mysql_servers(hostgroup_id,hostname,port,weight,comment) values(20,'192.168.159.144',3306,1,'Read Group');
Query OK, 1 row affected (0.00 sec)
MySQL [(none)]> select hostgroup_id,hostname,port,weight,comment from mysql_servers;
+--------------+-----------------+------+--------+-------------+
| hostgroup_id | hostname | port | weight | comment |
+--------------+-----------------+------+--------+-------------+
| 10 | 192.168.159.137 | 3306 | 1 | Write Group |
| 20 | 192.168.159.144 | 3306 | 1 | Read Group |
+--------------+-----------------+------+--------+-------------+
2 rows in set (0.00 sec)
//加载到runtime里去
MySQL [(none)]> load mysql servers to run;
Query OK, 0 rows affected (0.01 sec)
//保存到disk里去
MySQL [(none)]> save mysql servers to disk;
Query OK, 0 rows affected (0.00 sec)
//添加刚才在master上创建的账号 proxysql
//default_hostgroup 默认组设置为写组，也就是1;
MySQL [(none)]> insert into mysql_users(username,password,default_hostgroup,transaction_persistent)values('proxysql','aaa@qq.com',1,1);
Query OK, 1 row affected (0.00 sec)
MySQL [(none)]> select * from mysql_users \G
*************************** 1. row ***************************
username: proxysql # 后端mysql实例的用户名
password: aaa@qq.com # 后端mysql实例的密码
active: 1 # active=1表示用户生效，0表示不生效
use_ssl: 0
default_hostgroup: 1 # 用户默认登录到哪个hostgroup_id下的实例
default_schema: NULL # 用户默认登录后端mysql实例时连接的数据库，这个地方为NULL的话，则由全局变量mysql-default_schema决定，默认是information_schema
schema_locked: 0
transaction_persistent: 1 # 如果设置为1，连接上ProxySQL的会话后，如果在一个hostgroup上开启了事务，那么后续的sql都继续维持在这个hostgroup上，不论是否会匹配上其它路由规则，直到事务结束。虽然默认是0
fast_forward: 0 # 忽略查询重写/缓存层，直接把这个用户的请求透传到后端DB。相当于只用它的连接池功能，一般不用，路由规则 .* 就行了
backend: 1
frontend: 1
max_connections: 10000 # 该用户允许的最大连接数
comment:
1 row in set (0.00 sec)
//加载到runtime里去
MySQL [(none)]> load mysql users to run;
Query OK, 0 rows affected (0.00 sec)
//保存到disk里去
MySQL [(none)]> save mysql users to disk;
Query OK, 0 rows affected (0.00 sec)
2.4 添加健康检测的帐号
2.4.1 在主上添加属于proxysql的只读账号
MariaDB [(none)]> grant select on *.* to 'monitor'@'192.168.159.%' identified by 'monitor';
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> flush privileges;
Query OK, 0 rows affected (0.01 sec)
2.4.2 在proxysql主机端修改变量设置健康检测的账号
MySQL [(none)]> set mysql-monitor_username='monitor';
Query OK, 1 row affected (0.00 sec)
MySQL [(none)]> set mysql-monitor_password='monitor';
Query OK, 1 row affected (0.00 sec)
MySQL [(none)]> load mysql variables to run;
Query OK, 0 rows affected (0.00 sec
MySQL [(none)]> save mysql variables to disk;
Query OK, 134 rows affected (0.00 sec)
2.5 添加读写分离的路由规则
- 将 select 查询语句全部路由至 hostgroup_id=20的组(也就是读组)
- 但是 select * from tb for update 这样的语句是会修改数据的，所以需要单独定义，将它路由至 hostgroup_id=10的组(也就是写组)
- 其他没有被规则匹配到的组将会被路由至用户默认的组(mysql_users 表中的 default_hostgroup)
MySQL [(none)]> insert into mysql_query_rules(rule_id,active,match_digest,destination_hostgroup,apply)values(1,1,'^SELECT.*FOR UPDATE$',10,1);
Query OK, 1 row affected (0.00 sec)
MySQL [(none)]> insert into mysql_query_rules(rule_id,active,match_digest,destination_hostgroup,apply)values(30,1,'^SELECT',20,1);
Query OK, 1 row affected (0.00 sec)
MySQL [(none)]> insert into mysql_query_rules(rule_id,active,match_digest,destination_hostgroup,apply)values(2,1,"^SHOW",20,1);
Query OK, 1 row affected (0.00 sec)
MySQL [(none)]> select rule_id,active,match_digest,destination_hostgroup,apply from mysql_query_rules;
+---------+--------+----------------------+-----------------------+-------+
| rule_id | active | match_digest | destination_hostgroup | apply |
+---------+--------+----------------------+-----------------------+-------+
| 1 | 1 | ^SELECT.*FOR UPDATE$ | 10 | 1 |
| 2 | 1 | ^SHOW | 20 | 1 |
| 30 | 1 | ^SELECT | 20 | 1 |
+---------+--------+----------------------+-----------------------+-------+
3 rows in set (0.00 sec)
MySQL [(none)]> load mysql query rules to run;
Query OK, 0 rows affected (0.00 sec)
MySQL [(none)]> save mysql query rules to disk;
Query OK, 0 rows affected (0.00 sec)
2.6 验证读写分离
2.6.1 登录 proxysql 客户端
登录用户是刚才我们在 mysql_user 表中创建的用户，端口为6033
[aaa@qq.com ~]# mysql -uproxysql aaa@qq.com -h127.0.0.1 -P6033
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.5.30 (ProxySQL)
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;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| school |
| test |
+--------------------+
5 rows in set (0.00 sec)
2.6.2 修改数据库和查询
//创建两个数据库
MySQL [(none)]> create database teacher;
Query OK, 1 row affected (0.00 sec)
MariaDB [(none)]> create database sprite;
Query OK, 1 row affected (0.00 sec)
//查询数据库创建成功没
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| school |
| sprite |
| teacher |
| test |
+--------------------+
7 rows in set (0.00 sec)
2.6.3 验证读写分离是否成功
MySQL [(none)]> select * from stats_mysql_query_digest\G
*************************** 1. row ***************************
hostgroup: 10
schemaname: information_schema
username: proxysql
client_address:
digest: 0x7088F6EA1D547993
digest_text: create database sprite
count_star: 1
first_seen: 1597436113
last_seen: 1597436113
sum_time: 10000967
min_time: 10000967
max_time: 10000967
sum_rows_affected: 0
sum_rows_sent: 0
*************************** 2. row ***************************
hostgroup: 10
schemaname: information_schema
username: proxysql
client_address:
digest: 0x7A58004EB07C2DC9
digest_text: create database teacher
count_star: 1
first_seen: 1597435469
last_seen: 1597435469
sum_time: 10001950
min_time: 10001950
max_time: 10001950
sum_rows_affected: 0
sum_rows_sent: 0
*************************** 3. row ***************************
hostgroup: 20
schemaname: information_schema
username: proxysql
client_address:
digest: 0xFC83CD3FFE618224
digest_text: select @@Version
count_star: 1
first_seen: 1597435251
last_seen: 1597435251
sum_time: 2283
min_time: 2283
max_time: 2283
sum_rows_affected: 0
sum_rows_sent: 1
*************************** 4. row ***************************
hostgroup: 20
schemaname: information_schema
username: proxysql
client_address:
digest: 0x02033E45904D3DF0
digest_text: show databases
count_star: 1
first_seen: 1597436069
last_seen: 1597436069
sum_time: 864
min_time: 864
max_time: 864
sum_rows_affected: 0
sum_rows_sent: 6
*************************** 5. row ***************************
hostgroup: 1
schemaname: information_schema
username: proxysql
client_address:
digest: 0x02033E45904D3DF0
digest_text: show databases
count_star: 6
first_seen: 1597435164
last_seen: 1597435640
sum_time: 60006449
min_time: 10000188
max_time: 10001719
sum_rows_affected: 0
sum_rows_sent: 0
*************************** 6. row ***************************
hostgroup: 1
schemaname: information_schema
username: proxysql
client_address:
digest: 0xD98E7BF9DDFEA113
digest_text: KILL ?
count_star: 2
first_seen: 1597435617
last_seen: 1597435622
sum_time: 0
min_time: 0
max_time: 0
sum_rows_affected: 0
sum_rows_sent: 0
至此，读写分离成功！！！
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