MGR单主模式读写分离配置
实验环境信息
MySQL主从信息
| IP | 角色 |
|---|---|
| 188.188.0.68 | Master |
| 188.188.0.69 | Slave |
| 188.188.0.70 | Slave |
ProxySQL版本： 2.0.3-29-g00f26d5
MGR单主模式读写分离配置与传统主从读写分离配置相比，不同的地方主要为以下2点：
- 1、主从复制关系在表mysql_group_replication_hostgroups，而不是mysql_replication_hostgroups表。
- 2、后端的MySQL中，需要自建一个MGR状态信息视图:sys.gr_member_routing_candidate_status。
~
~
》》》服务器、用户配置篇《《《
1、添加后端数据库服务器
Admin> SELECT * FROM mysql_servers;
Empty set (0.00 sec)
Admin> INSERT INTO mysql_servers(hostgroup_id,hostname,port,comment)
-> VALUES
-> (1,'188.188.0.68',3306,'Master'),
-> (1,'188.188.0.69',3306,'Slave_1'),
-> (1,'188.188.0.70',3306,'Slave_2');
Query OK, 3 rows affected (0.00 sec)
Admin> SELECT * FROM mysql_servers;
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| 1 | 188.188.0.68 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | Master |
| 1 | 188.188.0.69 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | Slave_1 |
| 1 | 188.188.0.70 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | Slave_2 |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
3 rows in set (0.00 sec)2、配置监控
1）在MySQL中创建监控依赖视图
由于对MGR得监控是依赖于sys.gr_member_routing_candidate_status视图得，而该视图并非系统自带，所以需要手动建立。
相关脚本地址:https://github.com/lefred/mysql_gr_routing_check/下得addition_to_sys.sql脚本。
登录MGR得主节点，在sys库执行脚本：
# mysql -uroot -p -S /data/database-3306/mysql-3306.sock sys < /root/mysql_gr_routing_check-master/addition_to_sys.sql查看结果
mysql> show tables from sys like 'gr%';
+------------------------------------+
| Tables_in_sys (gr%) |
+------------------------------------+
| gr_member_routing_candidate_status |
+------------------------------------+
1 row in set (0.00 sec)视图已经建立。
2）添加ProXYSQL监视后MYSQL所需得用户（需要在MySQL Server中已创建该用户）：
MySQL中创建设置监控用户：
mysql> GRANT select on sys.gr_member_routing_candidate_status TO 'psql_monitor'@'188.188.0.%' IDENTIFIED BY '987654';
mysql> show grants for 'psql_monitor'@'188.188.0.%' ;
+--------------------------------------------------------------------------------------------+
| Grants for [email protected].% |
+--------------------------------------------------------------------------------------------+
| GRANT PROCESS, REPLICATION CLIENT ON *.* TO 'psql_monitor'@'188.188.0.%' |
| GRANT SELECT ON `sys`.`gr_member_routing_candidate_status` TO 'psql_monitor'@'188.188.0.%' |
+--------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)查看在ProxySQL中配置用户：
Admin> select * from global_variables where variable_name='mysql-monitor_username';
+------------------------+----------------+
| variable_name | variable_value |
+------------------------+----------------+
| mysql-monitor_username | monitor |
+------------------------+----------------+
1 row in set (0.00 sec)
Admin> select * from global_variables where variable_name='mysql-monitor_password';
+------------------------+----------------+
| variable_name | variable_value |
+------------------------+----------------+
| mysql-monitor_password | monitor |
+------------------------+----------------+
1 row in set (0.00 sec)配置监控用户：
Admin> UPDATE global_variables SET variable_value='psql_monitor' WHERE variable_name='mysql-monitor_username';
Query OK, 1 row affected (0.00 sec)
Admin> UPDATE global_variables SET variable_value='987654' WHERE variable_name='mysql-monitor_password';
Query OK, 1 row affected (0.01 sec)
Admin> select * from global_variables where variable_name='mysql-monitor_username';
+------------------------+----------------+
| variable_name | variable_value |
+------------------------+----------------+
| mysql-monitor_username | psql_monitor |
+------------------------+----------------+
1 row in set (0.00 sec)
Admin> select * from global_variables where variable_name='mysql-monitor_password';
+------------------------+----------------+
| variable_name | variable_value |
+------------------------+----------------+
| mysql-monitor_password | 987654 |
+------------------------+----------------+
1 row in set (0.00 sec)3）修改监控时间间隔
Admin> SELECT * FROM global_variables WHERE variable_name IN ('mysql-monitor_connect_interval','mysql-monitor_ping_interval','mysql-monitor_read_only_interval');
+----------------------------------+----------------+
| variable_name | variable_value |
+----------------------------------+----------------+
| mysql-monitor_connect_interval | 60000 |
| mysql-monitor_ping_interval | 10000 |
| mysql-monitor_read_only_interval | 1500 |
+----------------------------------+----------------+
3 rows in set (0.00 sec)
Admin> UPDATE global_variables SET variable_value='2000' WHERE variable_name IN ('mysql-monitor_connect_interval','mysql-monitor_ping_interval','mysql-monitor_read_only_interval');
Query OK, 3 rows affected (0.00 sec)4）配置的生效和持久化
加载配置到RUNTIME层：
Admin> LOAD MYSQL VARIABLES TO RUNTIME;
Query OK, 0 rows affected (0.00 sec)持久化配置到DISK层：
Admin> SAVE MYSQL VARIABLES TO DISK;
Query OK, 110 rows affected (0.02 sec)3、后端MySQL服务健康检测
1）查看后端连接状态：
Admin> SELECT * FROM monitor.mysql_server_connect_log ORDER BY time_start_us DESC LIMIT 10;
+--------------+------+------------------+-------------------------+---------------+
| hostname | port | time_start_us | connect_success_time_us | connect_error |
+--------------+------+------------------+-------------------------+---------------+
| 188.188.0.70 | 3306 | 1556620581265582 | 387 | NULL |
| 188.188.0.69 | 3306 | 1556620581239483 | 413 | NULL |
| 188.188.0.68 | 3306 | 1556620581213375 | 432 | NULL |
| 188.188.0.70 | 3306 | 1556620579255264 | 381 | NULL |
| 188.188.0.68 | 3306 | 1556620579234288 | 426 | NULL |
| 188.188.0.69 | 3306 | 1556620579213311 | 492 | NULL |
| 188.188.0.70 | 3306 | 1556620577259808 | 443 | NULL |
| 188.188.0.68 | 3306 | 1556620577236530 | 437 | NULL |
| 188.188.0.69 | 3306 | 1556620577213253 | 500 | NULL |
| 188.188.0.70 | 3306 | 1556620575249404 | 468 | NULL |
+--------------+------+------------------+-------------------------+---------------+
10 rows in set (0.00 sec)查看后端存活状态：
Admin> SELECT * FROM monitor.mysql_server_ping_log ORDER BY time_start_us DESC LIMIT 10;
+--------------+------+------------------+----------------------+------------+
| hostname | port | time_start_us | ping_success_time_us | ping_error |
+--------------+------+------------------+----------------------+------------+
| 188.188.0.70 | 3306 | 1556620607647791 | 85 | NULL |
| 188.188.0.68 | 3306 | 1556620607631491 | 80 | NULL |
| 188.188.0.69 | 3306 | 1556620607615190 | 89 | NULL |
| 188.188.0.70 | 3306 | 1556620605653805 | 83 | NULL |
| 188.188.0.69 | 3306 | 1556620605634458 | 85 | NULL |
| 188.188.0.68 | 3306 | 1556620605615106 | 88 | NULL |
| 188.188.0.70 | 3306 | 1556620603663711 | 84 | NULL |
| 188.188.0.68 | 3306 | 1556620603639370 | 93 | NULL |
| 188.188.0.69 | 3306 | 1556620603615027 | 94 | NULL |
| 188.188.0.69 | 3306 | 1556620601666891 | 81 | NULL |
+--------------+------+------------------+----------------------+------------+
10 rows in set (0.00 sec)2）配置的生效和持久化
确认后端服务正常后，就可以加载到RUNTIME层进行启用和持久化到DISK层：
Admin> SELECT * FROM runtime_mysql_servers;
Empty set (0.00 sec)
Admin> SELECT * FROM disk.mysql_servers;
Empty set (0.00 sec)加载配置到RUNTIME层：
Admin> LOAD MYSQL SERVERS TO RUNTIME;
Query OK, 0 rows affected (0.01 sec)持久化配置到DISK层：
Admin> SAVE MYSQL SERVERS TO DISK;
Query OK, 0 rows affected (0.03 sec)
Admin> 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 |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| 1 | 188.188.0.68 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | Master |
| 1 | 188.188.0.70 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | Slave_2 |
| 1 | 188.188.0.69 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | Slave_1 |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
3 rows in set (0.01 sec)这里得hostgroup_id都是1，因为我们还没有配置读写分离组信息。
Admin> SELECT * FROM disk.mysql_servers;
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| 1 | 188.188.0.68 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | Master |
| 1 | 188.188.0.70 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | Slave_2 |
| 1 | 188.188.0.69 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | Slave_1 |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
3 rows in set (0.01 sec)4、MySQL主从复制架构信息配置
1）新增主从配置
Admin> SELECT * FROM mysql_group_replication_hostgroups;
Empty set (0.00 sec插入读写、只读组配置信息：
Admin> INSERT INTO mysql_group_replication_hostgroups(writer_hostgroup,backup_writer_hostgroup,reader_hostgroup,offline_hostgroup,active,writer_is_also_reader,comment) VALUES (1,2,4,6,1,1,'MGR_MS');
Query OK, 1 row affected (0.00 sec)说明：写组编号为1，其他可写节点所在组为2(因为MGR可多主)，只读组为4，下线组为6；
Admin> select * from mysql_group_replication_hostgroups;
+------------------+-------------------------+------------------+-------------------+--------+-------------+-----------------------+-------------------------+---------+
| writer_hostgroup | backup_writer_hostgroup | reader_hostgroup | offline_hostgroup | active | max_writers | writer_is_also_reader | max_transactions_behind | comment |
+------------------+-------------------------+------------------+-------------------+--------+-------------+-----------------------+-------------------------+---------+
| 1 | 2 | 4 | 6 | 1 | 1 | 1 | 0 | MGR_MS |
+------------------+-------------------------+------------------+-------------------+--------+-------------+-----------------------+-------------------------+---------+
1 row in set (0.00 sec)2）配置生效
将修改的配置加载到RUNTIME层：
Admin> LOAD MYSQL SERVERS TO RUNTIME;
Query OK, 0 rows affected (0.00 sec)查看MySQL分组：
Admin> 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 |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| 1 | 188.188.0.68 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | Master |
| 4 | 188.188.0.70 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | Slave_2 |
| 4 | 188.188.0.69 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | Slave_1 |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
3 rows in set (0.00 sec)可以看到，最初hostgroup_id都为1，现在分为了1和2组。
3）查看MySQL状态
Admin> SELECT * FROM monitor.mysql_server_group_replication_log ORDER BY time_start_us DESC LIMIT 10;
+--------------+------+------------------+-----------------+------------------+-----------+---------------------+-------+
| hostname | port | time_start_us | success_time_us | viable_candidate | read_only | transactions_behind | error |
+--------------+------+------------------+-----------------+------------------+-----------+---------------------+-------+
| 188.188.0.70 | 3306 | 1558242135902746 | 1781 | YES | YES | 0 | NULL |
| 188.188.0.69 | 3306 | 1558242135902307 | 1730 | YES | YES | 0 | NULL |
| 188.188.0.68 | 3306 | 1558242135901846 | 1713 | YES | NO | 0 | NULL |
| 188.188.0.70 | 3306 | 1558242130902767 | 1773 | YES | YES | 0 | NULL |
| 188.188.0.69 | 3306 | 1558242130902313 | 1772 | YES | YES | 0 | NULL |
| 188.188.0.68 | 3306 | 1558242130901853 | 1753 | YES | NO | 0 | NULL |
| 188.188.0.70 | 3306 | 1558242125902588 | 1734 | YES | YES | 0 | NULL |
| 188.188.0.69 | 3306 | 1558242125902140 | 1743 | YES | YES | 0 | NULL |
| 188.188.0.68 | 3306 | 1558242125901685 | 1726 | YES | NO | 0 | NULL |
| 188.188.0.70 | 3306 | 1558242120902548 | 1788 | YES | YES | 0 | NULL |
+--------------+------+------------------+-----------------+------------------+-----------+---------------------+-------+
10 rows in set (0.01 sec)Slave的read_only属性都已识别到，而且没错误信息。
4）对配置存盘
Admin> SAVE MYSQL SERVERS TO DISK;
Query OK, 0 rows affected (0.03 sec)
Admin> SELECT * FROM disk.mysql_servers;
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| 1 | 188.188.0.68 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | Master |
| 1 | 188.188.0.69 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | Slave_1 |
| 1 | 188.188.0.70 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | Slave_2 |
+--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
3 rows in set (0.00 sec)5、设置MySQL Users(连接后端使用)
1）在后端MySQL创建业务账号
Admin> SELECT * FROM mysql_users;
Empty set (0.00 sec)-- 在后端MySQL上创建业务库及读写账号：
mysql> CREATE DATABASE test;
Query OK, 1 row affected (0.01 sec)
mysql> GRANT select,insert,update,delete ON test.* TO 'test_rw'@'188.188.0.%' IDENTIFIED BY '123456';
Query OK, 0 rows affected, 1 warning (0.00 sec)2）将业务账号加入ProxySQL
-- 添加后端MySQL上的业务账号到 mysql_users
Admin> INSERT INTO mysql_users(username,password,default_hostgroup) VALUES ('test_rw','123456',1);
Query OK, 1 row affected (0.00 sec)
Admin> SELECT * FROM mysql_users;
+----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+
| username | password | active | use_ssl | default_hostgroup | default_schema | schema_locked | transaction_persistent | fast_forward | backend | frontend | max_connections | comment |
+----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+
| test_rw | 123456 | 1 | 0 | 1 | NULL | 0 | 1 | 0 | 1 | 1 | 10000 | |
+----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+
3 rows in set (0.00 sec)3）配置的生效
再次，将配置加载到运行时以使其生效。
Admin> LOAD MYSQL USERS TO RUNTIME;
Query OK, 0 rows affected (0.00 sec)
Admin> SELECT * FROM runtime_mysql_users;
+----------+-------------------------------------------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+
| username | password | active | use_ssl | default_hostgroup | default_schema | schema_locked | transaction_persistent | fast_forward | backend | frontend | max_connections | comment |
+----------+-------------------------------------------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+
| test_rw | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | 1 | 0 | 1 | | 0 | 1 | 0 | 0 | 1 | 10000 | |
| test_rw | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | 1 | 0 | 1 | | 0 | 1 | 0 | 1 | 0 | 10000 | |
+----------+-------------------------------------------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+
2 rows in set (0.00 sec)被添加的每个用户出现了成对的记录，这是因为每个用户在前端和后端都有一条用户记录;
4）加密MEMORY层用户密码
从RUNTIME层获取用户加密后密码，更新MEMORY层：
Admin> SELECT * FROM mysql_users;
+----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+
| username | password | active | use_ssl | default_hostgroup | default_schema | schema_locked | transaction_persistent | fast_forward | backend | frontend | max_connections | comment |
+----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+
| test_rw | 123456 | 1 | 0 | 1 | NULL | 0 | 1 | 0 | 1 | 1 | 10000 | |
+----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+
1 row in set (0.00 sec)
Admin> SAVE MYSQL USERS FROM RUNTIME;
Query OK, 0 rows affected (0.00 sec)
Admin> SELECT * FROM mysql_users;
+----------+-------------------------------------------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+
| username | password | active | use_ssl | default_hostgroup | default_schema | schema_locked | transaction_persistent | fast_forward | backend | frontend | max_connections | comment |
+----------+-------------------------------------------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+
| test_rw | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | 1 | 0 | 1 | | 0 | 1 | 0 | 1 | 1 | 10000 | |
+----------+-------------------------------------------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+
1 row in set (0.00 sec)5）配置持久化
持久化用户信息到DISK层：
Admin> SELECT * FROM disk.mysql_users;
Empty set (0.00 sec)
Admin> SAVE MYSQL USERS TO DISK;
Query OK, 0 rows affected (0.01 sec)
Admin> SELECT * FROM disk.mysql_users;
+----------+-------------------------------------------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+
| username | password | active | use_ssl | default_hostgroup | default_schema | schema_locked | transaction_persistent | fast_forward | backend | frontend | max_connections | comment |
+----------+-------------------------------------------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+
| test_rw | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | 1 | 0 | 1 | | 0 | 1 | 0 | 1 | 1 | 10000 | |
+----------+-------------------------------------------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+
1 rows in set (0.00 sec)6、业务账号可用性验证
到此，用户添加完毕，可用使用客户端连接ProxySQL尝试连接。
Admin> select * from stats.stats_mysql_query_digest ;
Empty set (0.01 sec)ProxySQL中无SQL统计信息；
[root@localhost ~]# mysql -u test_rw -p123456 -h 188.188.0.71 -P6033 -e "SELECT 1"
mysql: [Warning] Using a password on the command line interface can be insecure.
+---+
| 1 |
+---+
| 1 |
+---+注意：连接端口默认是6033，不是6032(ProxySQL管理端口)也不是3306(MySQL端口)。
[root@localhost ~]# mysql -u test_rw -p123456 -h 188.188.0.71 -P6033 -e "SELECT @@port"
mysql: [Warning] Using a password on the command line interface can be insecure.
+--------+
| @@port |
+--------+
| 3306 |
+--------+这里查询出了后端MySQL服务的端口。
Admin> select * from stats.stats_mysql_query_digest ;
+-----------+--------------------+----------+----------------+--------------------+----------------------------------+------------+------------+------------+----------+----------+----------+
| hostgroup | schemaname | username | client_address | digest | digest_text | count_star | first_seen | last_seen | sum_time | min_time | max_time |
+-----------+--------------------+----------+----------------+--------------------+----------------------------------+------------+------------+------------+----------+----------+----------+
| 1 | information_schema | test_rw | | 0x1C46AE529DD5A40E | SELECT ? | 1 | 1558242482 | 1558242482 | 566 | 566 | 566 |
| 1 | information_schema | test_rw | | 0x831B091BA90D80E5 | SELECT @@port | 1 | 1558242494 | 1558242494 | 167 | 167 | 167 |
| 1 | information_schema | test_rw | | 0x226CD90D52A2BA0B | select @@version_comment limit ? | 2 | 1558242482 | 1558242494 | 0 | 0 | 0 |
+-----------+--------------------+----------+----------------+--------------------+----------------------------------+------------+------------+------------+----------+----------+----------+
3 rows in set (0.00 sec)执行得SQL都跑到了组1上，即Master上。这时只是最简单的服务器、用户配置已经完成，读写分离在后面继续介绍！！！
》》》读写分离查询规则配置篇《《《
- 注意：
正常逻辑应该是针对有必要的SQL进行读写分离配置，而不是粗暴的将所有查询都发送到Slave；
1、读写分离的正常逻辑
使用regex和digest进行读/写拆分是很正确的选择，有效设置读/写拆分的配置过程如下：
1）配置 ProxySQL 只将所有流量发送到一个 MySQL 节点——master(写和读);
2）在 stats_mysql_query_digest 中查找执行成本较高的 SELECT 语句;
3）确定哪些成本较高的 SELECT 语句应该被移动到Slave节点上执行；
4）配置 mysql_query_rules 将需要移动的 SELECT 语句发送到读节点；
因此，这个想法非常简单：只发送你想发送给 Slave/Reader 的内容，而不只是任何SELECT语句。
2、确定高成本的 SELECT 语句
可以从以下几种维度来查找成本较高的 SELECT 语句；
1）根据总执行时间查找最耗时的前5个查询：
Admin> SELECT digest,SUBSTR(digest_text,0,25),count_star,sum_time
-> FROM stats.stats_mysql_query_digest
-> WHERE digest_text LIKE 'SELECT%'
-> ORDER BY sum_time DESC
-> LIMIT 5;
+--------------------+--------------------------+------------+----------+
| digest | SUBSTR(digest_text,0,25) | count_star | sum_time |
+--------------------+--------------------------+------------+----------+
| 0x1C46AE529DD5A40E | SELECT ? | 1 | 543 |
| 0x38B78BFFAF23614A | select * from test.t1 | 1 | 356 |
| 0x831B091BA90D80E5 | SELECT @@port | 1 | 171 |
| 0x226CD90D52A2BA0B | select @@version_comment | 3 | 0 |
+--------------------+--------------------------+------------+----------+
4 rows in set (0.00 sec)2）根据计数查找前5个查询：
Admin> SELECT digest,SUBSTR(digest_text,0,25),count_star,sum_time
-> FROM stats_mysql_query_digest
-> WHERE digest_text LIKE 'SELECT%'
-> ORDER BY count_star DESC
-> LIMIT 5;
+--------------------+--------------------------+------------+----------+
| digest | SUBSTR(digest_text,0,25) | count_star | sum_time |
+--------------------+--------------------------+------------+----------+
| 0x226CD90D52A2BA0B | select @@version_comment | 3 | 0 |
| 0x38B78BFFAF23614A | select * from test.t1 | 1 | 356 |
| 0x1C46AE529DD5A40E | SELECT ? | 1 | 543 |
| 0x831B091BA90D80E5 | SELECT @@port | 1 | 171 |
+--------------------+--------------------------+------------+----------+
4 rows in set (0.01 sec)3）根据最长执行时间查找前5个查询：
Admin> SELECT digest,SUBSTR(digest_text,0,25),count_star,sum_time,sum_time/count_star avg_time, min_time, max_time
-> FROM stats_mysql_query_digest
-> WHERE digest_text LIKE 'SELECT%'
-> ORDER BY max_time DESC
-> LIMIT 5;
+--------------------+--------------------------+------------+----------+----------+----------+----------+
| digest | SUBSTR(digest_text,0,25) | count_star | sum_time | avg_time | min_time | max_time |
+--------------------+--------------------------+------------+----------+----------+----------+----------+
| 0x1C46AE529DD5A40E | SELECT ? | 1 | 543 | 543 | 543 | 543 |
| 0x38B78BFFAF23614A | select * from test.t1 | 1 | 356 | 356 | 356 | 356 |
| 0x831B091BA90D80E5 | SELECT @@port | 1 | 171 | 171 | 171 | 171 |
| 0x226CD90D52A2BA0B | select @@version_comment | 3 | 0 | 0 | 0 | 0 |
+--------------------+--------------------------+------------+----------+----------+----------+----------+
4 rows in set (0.00 sec)4）查找按总执行时间排序的前5个查询，最小执行时间至少为0.3毫秒：
Admin> SELECT digest,SUBSTR(digest_text,0,20),count_star,sum_time,sum_time/count_star avg_time, min_time, max_time
-> FROM stats_mysql_query_digest
-> WHERE digest_text LIKE 'SELECT%' AND min_time > 300
-> ORDER BY sum_time DESC
-> LIMIT 5;
+--------------------+--------------------------+------------+----------+----------+----------+----------+
| digest | SUBSTR(digest_text,0,20) | count_star | sum_time | avg_time | min_time | max_time |
+--------------------+--------------------------+------------+----------+----------+----------+----------+
| 0x1C46AE529DD5A40E | SELECT ? | 1 | 543 | 543 | 543 | 543 |
| 0x38B78BFFAF23614A | select * from test. | 1 | 356 | 356 | 356 | 356 |
+--------------------+--------------------------+------------+----------+----------+----------+----------+
2 rows in set (0.01 sec)5）查找按总执行时间排序的前5个查询，平均执行时间至少为0.3毫秒。同时显示总执行时间的百分比：
Admin> SELECT digest,SUBSTR(digest_text,0,25),count_star,sum_time,sum_time/count_star avg_time, ROUND(sum_time*100.00/(SELECT SUM(sum_time)
-> FROM stats_mysql_query_digest),3) pct FROM stats_mysql_query_digest
-> WHERE digest_text LIKE 'SELECT%' AND sum_time/count_star > 300
-> ORDER BY sum_time DESC
-> LIMIT 5;
+--------------------+--------------------------+------------+----------+----------+--------+
| digest | SUBSTR(digest_text,0,25) | count_star | sum_time | avg_time | pct |
+--------------------+--------------------------+------------+----------+----------+--------+
| 0x1C46AE529DD5A40E | SELECT ? | 1 | 543 | 543 | 50.748 |
| 0x38B78BFFAF23614A | select * from test.t1 | 1 | 356 | 356 | 33.271 |
+--------------------+--------------------------+------------+----------+----------+--------+
2 rows in set (0.01 sec)通过以上5个维度，大致可以找出目标SQL了。
这里，我们将 'select * from test.t1' 作为选定的目标，将其分配到Slave上进行读取。
3、编写查询规则
在与应用程序开发人员确认之后，可以将'select * from test.t1'的语句，即digset为 0x38B78BFFAF23614A 的查询转移到Slave_1上执行：
Admin> SELECT * FROM mysql_query_rules ;
Empty set (0.00 sec)
Admin> INSERT INTO mysql_query_rules (rule_id,active,digest,destination_hostgroup,apply) VALUES (1,1,'0x38B78BFFAF23614A',4,1);
Query OK, 1 row affected (0.00 sec)注意:这里destination_hostgroup为4号的只读组。
Admin> SELECT * FROM mysql_query_rules \G
*************************** 1. row ***************************
rule_id: 1
active: 1
username: NULL
schemaname: NULL
flagIN: 0
client_addr: NULL
proxy_addr: NULL
proxy_port: NULL
digest: 0x38B78BFFAF23614A
match_digest: NULL
match_pattern: NULL
negate_match_pattern: 0
re_modifiers: CASELESS
flagOUT: NULL
replace_pattern: NULL
destination_hostgroup: 4
cache_ttl: NULL
cache_empty_result: NULL
cache_timeout: NULL
reconnect: NULL
timeout: NULL
retries: NULL
delay: NULL
next_query_flagIN: NULL
mirror_flagOUT: NULL
mirror_hostgroup: NULL
error_msg: NULL
OK_msg: NULL
sticky_conn: NULL
multiplex: NULL
gtid_from_hostgroup: NULL
log: NULL
apply: 1
comment: NULL
1 row in set (0.00 sec)4、配置生效
Admin> LOAD MYSQL QUERY RULES TO RUNTIME;
Query OK, 0 rows affected (0.00 sec)
Admin> SELECT * FROM runtime_mysql_query_rules \G
*************************** 1. row ***************************
rule_id: 1
active: 1
username: NULL
schemaname: NULL
flagIN: 0
client_addr: NULL
proxy_addr: NULL
proxy_port: NULL
digest: 0x38B78BFFAF23614A
match_digest: NULL
match_pattern: NULL
negate_match_pattern: 0
re_modifiers: CASELESS
flagOUT: NULL
replace_pattern: NULL
destination_hostgroup: 4
cache_ttl: NULL
cache_empty_result: NULL
cache_timeout: NULL
reconnect: NULL
timeout: NULL
retries: NULL
delay: NULL
next_query_flagIN: NULL
mirror_flagOUT: NULL
mirror_hostgroup: NULL
error_msg: NULL
OK_msg: NULL
sticky_conn: NULL
multiplex: NULL
gtid_from_hostgroup: NULL
log: NULL
apply: 1
comment: NULL
1 row in set (0.00 sec)5、验证设置结果
1）记录SQL的历史状态信息
Admin> SELECT * FROM stats.stats_mysql_query_digest WHERE digest='0x38B78BFFAF23614A';
+-----------+--------------------+----------+----------------+--------------------+-----------------------+------------+------------+------------+----------+----------+----------+
| hostgroup | schemaname | username | client_address | digest | digest_text | count_star | first_seen | last_seen | sum_time | min_time | max_time |
+-----------+--------------------+----------+----------------+--------------------+-----------------------+------------+------------+------------+----------+----------+----------+
| 1 | information_schema | test_rw | | 0x38B78BFFAF23614A | select * from test.t1 | 1 | 1557977769 | 1557977769 | 356 | 356 | 356 |
+-----------+--------------------+----------+----------------+--------------------+-----------------------+------------+------------+------------+----------+----------+----------+
1 rows in set (0.00 sec)
Admin> SELECT * FROM stats.stats_mysql_query_rules WHERE rule_id=1;
Empty set (0.00 sec)2）使用业务账号向ProxySQL发出目标SQL：
[root@localhost ~]# mysql -u test_rw -p123456 -h 188.188.0.71 -P6033 -e "select * from test.t1;"
mysql: [Warning] Using a password on the command line interface can be insecure.
+----+------+
| id | name |
+----+------+
| 1 | a |
| 2 | b |
+----+------+3）在ProxySQL中查看查询设置结果
Admin> SELECT * FROM stats.stats_mysql_query_digest WHERE digest='0x38B78BFFAF23614A';
+-----------+--------------------+----------+----------------+--------------------+-----------------------+------------+------------+------------+----------+----------+----------+
| hostgroup | schemaname | username | client_address | digest | digest_text | count_star | first_seen | last_seen | sum_time | min_time | max_time |
+-----------+--------------------+----------+----------------+--------------------+-----------------------+------------+------------+------------+----------+----------+----------+
| 4 | information_schema | test_rw | | 0x38B78BFFAF23614A | SELECT * from test.t1 | 1 | 1558243463 | 1558243463 | 793 | 793 | 793 |
| 1 | information_schema | test_rw | | 0x38B78BFFAF23614A | select * from test.t1 | 1 | 1557977769 | 1557977769 | 356 | 356 | 356 |
+-----------+--------------------+----------+----------------+--------------------+-----------------------+------------+------------+------------+----------+----------+----------+
2 rows in set (0.00 sec)出现了hostgroup 2的查询记录，说明已经将目标SQL发送到了Slave服务上。
Admin> SELECT * FROM stats.stats_mysql_query_rules WHERE rule_id=1;
+---------+------+
| rule_id | hits |
+---------+------+
| 1 | 1 |
+---------+------+
1 row in set (0.00 sec)规则被命中1次。
以上2个结果说明了目标SQL通过查询规则被发送到了Slave上。
6、配置持久化
Admin> SELECT * FROM disk.mysql_query_rules WHERE rule_id=1 ;
Empty set (0.00 sec)
Admin> SAVE MYSQL QUERY RULES TO DISK;
Query OK, 0 rows affected (0.01 sec)
Admin> SELECT * FROM disk.mysql_query_rules WHERE rule_id=1 \G
*************************** 1. row ***************************
rule_id: 1
active: 1
username: NULL
schemaname: NULL
flagIN: 0
client_addr: NULL
proxy_addr: NULL
proxy_port: NULL
digest: 0x38B78BFFAF23614A
match_digest: NULL
match_pattern: NULL
negate_match_pattern: 0
re_modifiers: CASELESS
flagOUT: NULL
replace_pattern: NULL
destination_hostgroup: 4
cache_ttl: NULL
cache_empty_result: NULL
cache_timeout: NULL
reconnect: NULL
timeout: NULL
retries: NULL
delay: NULL
next_query_flagIN: NULL
mirror_flagOUT: NULL
mirror_hostgroup: NULL
error_msg: NULL
OK_msg: NULL
sticky_conn: NULL
multiplex: NULL
gtid_from_hostgroup: NULL
log: NULL
apply: 1
comment: NULL
1 row in set (0.00 sec)到此，利用ProxySQL对传统的主从结构读写分离已经实现。
》》》系统参数配置篇《《《
修改自动提交参数：
Admin> show variables like '%auto%';
+---------------------------------------+-------+
| Variable_name | Value |
+---------------------------------------+-------+
| mysql-forward_autocommit | false |
| mysql-enforce_autocommit_on_reads | false |
| mysql-autocommit_false_not_reusable | false |
| mysql-autocommit_false_is_transaction | false |
| mysql-auto_increment_delay_multiplex | 5 |
+---------------------------------------+-------+
5 rows in set (0.01 sec)修改以下2个参数：
1)
Admin> set mysql-forward_autocommit='true';为true时，则SET autocommit = 0命令被转发到MySQL上后端。
2)
Admin> set mysql-autocommit_false_not_reusable = 'true';设置为true时，不会重新使用与autocommit = 0的连接，并在连接返回到连接池时销毁
使配置生效
Admin> save mysql variables to disk;使配置持久化
Admin> load mysql variables to run;》》》压测篇《《《
后端为MGR单主模式
可以直接用多线程压测PROXYSQL，就像压测普通MySQL一样。但要注意：
由于ProxySQL监控主从状态是靠在后端MySQL上建立一个sys.gr_member_routing_candidate_status的状态视图，而对该视图的查询实际上是对多个系统表查询结果的汇总。因此，在MySQL繁忙时访问该视图会导致监控程序获取信息超时而失败，继而误判主机状态而修改runtime_mysql_servers的状态，导致连接后端MGR线程断开。所以，压测时最好将该视图用一个同名表代替，并在里面写死服务器状态，这样就不会在监控程序访问时获取内容超时而误判异常，也就不会杀死后端连接线程。
~
~
完毕!