在美團點評DBProxy讀寫分離使用說明文章中已經說明了使用目的，本文介紹ProxySQL的使用方法以及和DBProxy的性能差異。具體的介紹可以看官網的相關說明，并且這個中間件也是percona推的一款中間件。其特性和其他讀寫分離的中間件差距不大，具體的會在文中介紹。本文大致簡單的介紹在使用過程中的一些說明，也可以看官方的wiki獲得使用幫助。
環境：?
Distributor ID： ? ?Ubuntu
Description： ? ?Ubuntu 14.04.5 LTS
Release： ? ?14.04Codename： ? ?trusty
下載
percona站點：
https：//www.percona.com/downloads/proxysql/
github/官網：
https：//github.com/sysown/proxysql/releases
我們首先看一下自己的環境：
MHA已經搭建：
master：172.16.16.35:3306slave：172.16.16.35:3307slave：172.16.16.34:3307
MHA manager在172.16.16.34，配置文件如下：
[root@localhost bin]# cat /etc/masterha/app1.cnf [server default] manager_log=/var/log/mha/app1/manager.log manager_workdir=/var/log/mha/app1.log master_binlog_dir=/home/mysql/db3306/log/master_ip_failover_script=/usr/local/bin/master_ip_failover master_ip_online_change_script=/usr/local/bin/master_ip_online_change password=123456ping_interval=1remote_workdir=/tmp repl_password=123456repl_user=root report_script=/usr/local/bin/send_report shutdown_script=""ssh_user=root user=root [server1] hostname=172.16.16.35port=3306[server2] candidate_master=1check_repl_delay=0hostname=172.16.16.34port=3306[server3] hostname=172.16.16.35port=3307
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下面我們基于這樣一套MHA環境搭建讀寫分離。
1：安裝ProxySQL軟件，這個我們部署到172.16.16.34上
[root@localhost bin]# sudo yum install http://www.percona.com/downloads/percona-release/redhat/0.1-4/percona-release-0.1-4.noarch.rpm[root@localhost bin]# yum install proxysql
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最后有以下提示：
Installed: proxysql.x86_64 0:1.3.7-1.1.el6 Complete!
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也就是安裝完成了。然后查一下具體的文件：
[root@localhost bin]# find / -name proxysql/var/lib/proxysql/var/run/proxysql/etc/rc.d/init.d/proxysql/usr/bin/proxysql
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發現確實已經將ProxySQL安裝成功了
2：啟動配置ProxySQL
看一下配置文件：
[root@localhost bin]# cat /etc/proxysql-admin.cnf # proxysql admin interface credentials. export PROXYSQL_USERNAME="admin"export PROXYSQL_PASSWORD="admin"export PROXYSQL_HOSTNAME="localhost"export PROXYSQL_PORT="6032" # PXC admin credentials for connecting to pxc-cluster-node. export CLUSTER_USERNAME="admin"export CLUSTER_PASSWORD="admin"export CLUSTER_HOSTNAME="localhost"export CLUSTER_PORT="3306" # proxysql monitoring user. proxysql admin script will create this user in pxc to monitor pxc-nodes. export MONITOR_USERNAME="monitor"export MONITOR_PASSWORD="monit0r" # Application user to connect to pxc-node through proxysql export CLUSTER_APP_USERNAME="proxysql_user"export CLUSTER_APP_PASSWORD="passw0rd" # ProxySQL read/write hostgroup export WRITE_HOSTGROUP_ID="10"export READ_HOSTGROUP_ID="11" # ProxySQL read/write configuration mode. export MODE="singlewrite"
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啟動：
[root@localhost bin]# proxysql-admin --config-file=/etc/proxysql-admin.cnf --enable This script will assist with configuring ProxySQL (currently only Percona XtraDB cluster in combination with ProxySQL is supported) ProxySQL read/write configuration mode is singlewrite ProxySQL is not running; please start the proxysql service
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現在來說ProxySQL 的路由已經啟動，提示我們要啟動proxysql service
[root@localhost bin]# service proxy proxy proxysql proxysql-admin proxysql_galera_checker proxysql_node_monitor [root@localhost bin]# service proxysql start Starting ProxySQL: DONE![root@localhost bin]# mysql -uadmin -padmin -h127.0.0.1 -P6032 mysql: [Warning] Using a password on the command line interface can be insecure. Welcome to the MySQL monitor. Commands end with ; or g. Your MySQL connection id is 1Server version: 5.7.14 (ProxySQL Admin Module) Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or 'h' for help. Type 'c' to clear the current input statement. mysql>
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可以看到我們已經登錄成功了，這里要說明的是 proxysql的默認配置文件是在：
[root@localhost bin]# find / -name proxysql.cnf/etc/proxysql.cnf
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接下來我們開始配置ProxySQL：
[root@localhost bin]# mysql -uadmin -padmin -h127.0.0.1 -P6032 mysql: [Warning] Using a password on the command line interface can be insecure. Welcome to the MySQL monitor. Commands end with ; or g. Your MySQL connection id is 2Server version: 5.7.14 (ProxySQL Admin Module) Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or 'h' for help. Type 'c' to clear the current input statement. mysql> show databases;+-----+---------+-------------------------------+ | seq | name | file | +-----+---------+-------------------------------+ | 0 | main | | | 2 | disk | /var/lib/proxysql/proxysql.db | | 3 | stats | | | 4 | monitor | | +-----+---------+-------------------------------+4 rows in set (0.00 sec) mysql> use admin Database changed mysql> show tables;+--------------------------------------+ | tables | +--------------------------------------+ | global_variables | | mysql_collations | | mysql_query_rules | | mysql_replication_hostgroups | | mysql_servers | | mysql_users | | runtime_global_variables | | runtime_mysql_query_rules | | runtime_mysql_replication_hostgroups | | runtime_mysql_servers | | runtime_mysql_users | | runtime_scheduler | | scheduler | +--------------------------------------+13 rows in set (0.00 sec)
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下面加入主從信息：
mysql> insert into mysql_servers(hostgroup_id,hostname,port,weight,max_connections,max_replication_lag,comment) values(100,'172.16.16.35',3306,1,1000,10,'test'); Query OK, 1 row affected (0.00 sec) mysql> insert into mysql_servers(hostgroup_id,hostname,port,weight,max_connections,max_replication_lag,comment) values(101,'172.16.16.34',3306,1,1000,10,'test'); Query OK, 1 row affected (0.00 sec) mysql> insert into mysql_servers(hostgroup_id,hostname,port,weight,max_connections,max_replication_lag,comment) values(101,'172.16.16.35',3307,1,1000,10,'test'); Query OK, 1 row affected (0.00 sec) mysql> select * from mysql_servers;+--------------+--------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | hostgroup_id | hostname | port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment | +--------------+--------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | 100 | 172.16.16.35 | 3306 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | test | | 101 | 172.16.16.34 | 3306 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | test | | 101 | 172.16.16.35 | 3307 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | test | +--------------+--------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+3 rows in set (0.00 sec)
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然后添加讀寫映射（主要是MHA后端切換的時候保證ProxySQL也能夠自動切換）：
mysql> insert into mysql_replication_hostgroups values(100,101,'masterha') ; Query OK, 1 row affected (0.00 sec) mysql> select * from mysql_replication_hostgroups;+------------------+------------------+----------+ | writer_hostgroup | reader_hostgroup | comment | +------------------+------------------+----------+ | 100 | 101 | masterha | +------------------+------------------+----------+1 row in set (0.00 sec)
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為ProxySQL添加監控賬號：
mysql> GRANT SUPER, REPLICATION CLIENT ON *.* TO 'proxysql'@'172.16.16.%' IDENTIFIED BY 'proxysql'; Query OK, 0 rows affected, 1 warning (0.09 sec) mysql> flush privileges; Query OK, 0 rows affected (0.10 sec)
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配置監控賬號（在proxySQL當中進行配置）：
mysql> set mysql-monitor_username='proxysql'; Query OK, 1 row affected (0.00 sec) mysql> set mysql-monitor_password='proxysql'; Query OK, 1 row affected (0.00 sec) mysql> load mysql variables to runtime; Query OK, 0 rows affected (0.00 sec) mysql> save mysql variables to disk; Query OK, 74 rows affected (0.02 sec)
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PS:有時候runtime_mysql_servers的status不為ONLINE狀態的話可以通過查看monitor.mysql_server_ping_log這個表來查看具體的報錯信息。
mysql> select * from monitor.mysql_server_ping_log;
然后配置程序賬號，簡單點統一使用root：123456最高權限來配置：
mysql> insert into mysql_users(username,password,active,default_hostgroup,transaction_persistent) values('root','123456',1,100,1); Query OK, 1 row affected (0.00 sec) mysql> select * from mysql_users;+----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+ | username | password | active | use_ssl | default_hostgroup | default_schema | schema_locked | transaction_persistent | fast_forward | backend | frontend | max_connections | +----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+ | root | 123456 | 1 | 0 | 100 | NULL | 0 | 1 | 0 | 1 | 1 | 10000 | +----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+1 row in set (0.00 sec)
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配置完成以后開始重新加載和保存我們的配置：
mysql> load mysql servers to runtime; Query OK, 0 rows affected (0.01 sec) mysql> save mysql servers to disk; Query OK, 0 rows affected (0.08 sec) mysql> load mysql users to runtime; Query OK, 0 rows affected (0.00 sec) mysql> save mysql users to disk; Query OK, 0 rows affected (0.03 sec)
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接下來開始配置路由規則：
mysql> INSERT INTO mysql_query_rules(active,match_pattern,destination_hostgroup,apply) VALUES(1,'^SELECT.*FOR UPDATE$',100,1); Query OK, 1 row affected (0.01 sec) mysql> INSERT INTO mysql_query_rules(active,match_pattern,destination_hostgroup,apply) VALUES(1,'^SELECT',101,1); Query OK, 1 row affected (0.00 sec) mysql> LOAD MYSQL QUERY RULES TO RUNTIME; Query OK, 0 rows affected (0.00 sec) mysql> SAVE MYSQL QUERY RULES TO DISK; Query OK, 0 rows affected (0.04 sec)
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至此配置已經完成了
3：測試讀寫分離
在172.16.16.35上鏈接proxySQL端口6033，并且做簡單的select操作：
[root@localhost ~]# mysql -uroot -p123456 -h172.16.16.34 -P6033 mysql: [Warning] Using a password on the command line interface can be insecure. Welcome to the MySQL monitor. Commands end with ; or g. Your MySQL connection id is 22Server version: 5.7.14 (ProxySQL) Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or 'h' for help. Type 'c' to clear the current input statement. mysql> select * from maxiangqian.test;+-----+------+ | id | name | +-----+------+ | 1 | qq | | 2 | qq | | 4 | aa | | 11 | a | | 111 | a | +-----+------+5 rows in set (0.04 sec)
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然后在進行查詢看一下：
mysql> select * from stats_mysql_query_digest;
可以看到已經完成了讀寫分離了。
mysql> select @@server_id;+-------------+ | @@server_id | +-------------+ | 353307 | +-------------+1 row in set (0.01 sec)
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查看一下server ID已經路由到了172.16.16.35:3307這個從庫上了。
測一下for update：
mysql> select * from maxiangqian.test for update;+-----+------+ | id | name | +-----+------+ | 1 | qq | | 2 | qq | | 4 | aa | | 11 | a | | 111 | a | +-----+------+5 rows in set (0.00 sec)
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再查看
mysql> select * from stats_mysql_query_digest;
已經自動路由到了主庫。
至此ProxySQL+MySQL MHA讀寫分離測試完成。。。未完待續
5：關于ProxySQL的思考以及簡單的命令
ProxySQL通過以上方式是可以實現讀寫分離，但是這種方式真的就沒有問題了嗎，如果是一些比如查詢訂單狀態的這種要求實時性非常高的SQL的話，似乎被路由到了從庫就會出現BUG。我們可以選擇在程序端控制這些參數，ProxySQL只作為一個負載均衡來使用，給ProxySQL創建多個賬號，一個讀寫，一個只讀。然后程序去實現讀寫分離。
ProxySQL是分三層來設計運行的，分別為RUNTIME ，MEMORY ，DISK ：
RUNTIME 代表的是ProxySQL當前生效的配置，包括 global_variables, mysql_servers, mysql_users, mysql_query_rules。無法直接修改這里的配置，必須要從下一層load進來。
MEMORY 是平時在mysql命令行修改的 main 里頭配置，可以認為是SQLite數據庫在內存的鏡像
DISK / CONFIG FILE 持久存儲的那份配置，一般在$(DATADIR)/proxysql.db，在重啟的時候會從硬盤里加載。 /etc/proxysql.cnf文件只在第一次初始化的時候用到，完了后，如果要修改監聽端口，還是需要在管理命令行里修改，再 save 到硬盤
常用命令：
LOAD MYSQL SERVERS TO RUNTIME — 讓修改的配置生效，也就是從MEMORY 把參數LOAD過來，等價于LOAD MYSQL USERS FROM MEMORY，這個語句的語法比較單間，FROM代表從上層LOAD過來，TO代表從本層到某一個層。比如前面我們設置了MySQL的監控賬號，但是還是要執行LOAD和SAVE保存變量并且使變量生效。
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