ProxySQL+Mysql实现数据库读写分离实战
ProxySQL介绍
ProxySQL是一个高性能的MySQL中间件，拥有强大的规则引擎。具有以下特性：http://www.proxysql.com/
- 1、连接池，而且是multiplexing
- 2、主机和用户的最大连接数限制
- 3、自动下线后端DB
延迟超过阀值
ping 延迟超过阀值
网络不通或宕机 - 4、强大的规则路由引擎
实现读写分离
查询重写
sql流量镜像 - 5、支持prepared statement
- 6、支持Query Cache
- 7、支持负载均衡，与gelera结合自动failover
整体环境介绍
1、系统环境
三台服务器系统环境一致如下
[root@db1 ~]# cat /etc/redhat-release
CentOS Linux release 7.4.1708 (Core)
[root@db1 ~]# uname -r
3.10.0-693.el7.x86_64
2、IP地址与软件版本
proxy 192.168.22.171
db1 192.168.22.173
db2 192.168.22.174
mysql 5.7.17
proxy sql 1.4.8
3、关闭防火墙、selinux
systemctl stop firewalld #停止防火墙服务
systemctl disable firewalld #禁止开机自启动
sed -i 's#SELINUX=enforcing#SELINUX=disabled#g' /etc/selinux/conf && reboot
#用sed命令替换的试修改selinux的配置文件
4、mysql安装与主从同步
安装请参考以下文章
LAMP架构应用实战——MySQL服务
主从同步请参以下文章
安装布署过程
1、数据库主从同步
查看主从同步状态
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.22.173
Master_User: rep
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: master-log.000001
Read_Master_Log_Pos: 154
Relay_Log_File: db2-relay-bin.000002
Relay_Log_Pos: 321
Relay_Master_Log_File: master-log.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: 154
Relay_Log_Space: 526
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: 1
Master_UUID: 70a61633-63ae-11e8-ab86-000c29fe99ea
Master_Info_File: /mysqldata/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.00 sec)
检测主从同步
[root@db1 ~]# mysql -uroot -p -e "create database testdb;"
Enter password:
[root@db1 ~]# mysql -uroot -p -e "show databases;" |grep testdb
Enter password:
testdb
#db2上查看是否同步
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| testdb |
+--------------------+
5 rows in set (0.01 sec)
2、准备proxySQL软件
[root@proxy ~]# wget https://github.com/sysown/proxysql/releases/download/v1.4.8/proxysql-1.4.8-1-centos7.x86_64.rpm
[root@proxy ~]# ll proxysql-1.4.8-1-centos7.x86_64.rpm
-rw-r--r-- 1 root root 5977168 Apr 10 11:38 proxysql-1.4.8-1-centos7.x86_64.rpm
3、安装配置
[root@proxy ~]# yum install -y proxysql-1.4.8-1-centos7.x86_64.rpm
[root@proxy ~]# rpm -ql proxysql
/etc/init.d/proxysql #启动脚本
/etc/proxysql.cnf #配置文件，仅在第一次(/var/lib/proxysql/proxysql.db文件不存在)启动时有效。启#动后可以在proxysql管理端中通过修改数据库的方式修改配置并生效(官方推荐方式。)
/usr/bin/proxysql #主程序文件
/usr/share/proxysql/tools/proxysql_galera_checker.sh
/usr/share/proxysql/tools/proxysql_galera_writer.pl
4、配置文件详解
[root@proxy ~]# egrep -v "^#|^$" /etc/proxysql.cnf
datadir="/var/lib/proxysql" #数据目录
admin_variables=
{
admin_credentials="admin:admin" #连接管理端的用户名与密码
mysql_ifaces="0.0.0.0:6032" #管理端口，用来连接proxysql的管理数据库
}
mysql_variables=
{
threads=4 #指定转发端口开启的线程数量
max_connections=2048
default_query_delay=0
default_query_timeout=36000000
have_compress=true
poll_timeout=2000
interfaces="0.0.0.0:6033" #指定转发端口，用于连接后端mysql数据库的，相当于代理作用
default_schema="information_schema"
stacksize=1048576
server_version="5.5.30" #指定后端mysql的版本
connect_timeout_server=3000
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
}
mysql_servers =
(
)
mysql_users:
(
)
mysql_query_rules:
(
)
scheduler=
(
)
mysql_replication_hostgroups=
(
)
#因此我们使用官方推荐的方式来配置proxy sql
5、启动服务并查看
[root@proxy ~]# /etc/init.d/proxysql start
Starting ProxySQL: DONE!
[root@proxy ~]# ss -lntup|grep proxy
tcp LISTEN 0 128 *:6032 *:* users:(("proxysql",pid=1199,fd=23))
tcp LISTEN 0 128 *:6033 *:* users:(("proxysql",pid=1199,fd=22))
tcp LISTEN 0 128 *:6033 *:* users:(("proxysql",pid=1199,fd=21))
tcp LISTEN 0 128 *:6033 *:* users:(("proxysql",pid=1199,fd=20))
tcp LISTEN 0 128 *:6033 *:* users:(("proxysql",pid=1199,fd=19))
#可以看出转发端口6033是启动了四个线程
6、在mysql上配置账号并授权
mysql> GRANT ALL ON *.* TO 'proxysql'@'192.168.22.%' IDENTIFIED BY '123456';
Query OK, 0 rows affected, 1 warning (0.03 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.02 sec)
7、proxysql默认数据库说明
[root@proxy ~]# yum install mysql -y
[root@proxy ~]# 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, 2017, 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)
main：内存配置数据库，表里存放后端db实例、用户验证、路由规则等信息。表名以 runtime_开头的表示proxysql当前运行的配置内容，不能通过dml语句修改，只能修改对应的不以 runtime_ 开头的（在内存）里的表，然后 LOAD 使其生效， SAVE 使其存到硬盘以供下次重启加载。
disk：是持久化到硬盘的配置，sqlite数据文件。
stats：是proxysql运行抓取的统计信息，包括到后端各命令的执行次数、流量、processlist、查询种类汇总/执行时间等等。
monitor：库存储 monitor 模块收集的信息，主要是对后端db的健康/延迟检查。
8、proxysql的配置系统
ProxySQL具有一个复杂但易于使用的配置系统，可以满足以下需求：
- 1、允许轻松动态更新配置（这是为了让ProxySQL用户可以在需要零宕机时间配置的大型基础架构中使用它）。与MySQL兼容的管理界面可用于此目的。
- 2、允许尽可能多的配置项目动态修改，而不需要重新启动ProxySQL进程
- 3、可以毫不费力地回滚无效配置
- 4、这是通过多级配置系统实现的，其中设置从运行时移到内存，并根据需要持久保存到磁盘。
3级配置由以下几层组成：
+-------------------------+
| RUNTIME |
+-------------------------+
/|\ |
| |
[1] | [2] |
| \|/
+-------------------------+
| MEMORY |
+-------------------------+ _
/|\ | |\
| | \
[3] | [4] | \ [5]
| \|/ \
+-------------------------+ +-------------------------+
| DISK | | CONFIG FILE |
+-------------------------+ +-------------------------+
参考文章：https://github.com/sysown/proxysql/wiki/Configuring-ProxySQL
9、配置proxysql管理用户
proxysql默认的表信息如下
MySQL [main]> show tables;
+--------------------------------------------+
| tables |
+--------------------------------------------+
| global_variables |
| mysql_collations |
| mysql_group_replication_hostgroups |
| mysql_query_rules |
| mysql_query_rules_fast_routing |
| mysql_replication_hostgroups |
| mysql_servers |
| mysql_users |
| proxysql_servers |
| runtime_checksums_values |
| runtime_global_variables |
| 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_scheduler |
| scheduler |
+--------------------------------------------+
20 rows in set (0.00 sec)
#这里是使用insert into语句来动态配置，而可以不需要重启
MySQL [(none)]> insert into mysql_servers(hostgroup_id,hostname,port,weight,comment) values(1,'db1','3306',1,'Write Group');
Query OK, 1 row affected (0.01 sec)
MySQL [(none)]> insert into mysql_servers(hostgroup_id,hostname,port,weight,comment) values(2,'db2','3307',1,'Read Group');
Query OK, 1 row affected (0.00 sec)
MySQL [(none)]> select * from mysql_servers;
+--------------+----------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+-------------+
| hostgroup_id | hostname | port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment |
+--------------+----------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+-------------+
| 1 | db1 | 3306 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | Write Group |
| 2 | db2 | 3307 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | Read Group |
+--------------+----------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+-------------+
2 rows in set (0.00 sec)
#接下来将刚刚在mysql客户端创建的用户写入到proxy sql主机的mysql_users表中，它也是用于proxysql客户端访问数据库，默认组是写组，当读写分离规则出现问题时，它会直接访问默认组的数据库。
MySQL [main]> INSERT INTO mysql_users(username,password,default_hostgroup) VALUES ('proxysql','123456',1);
Query OK, 1 row affected (0.00 sec)
MySQL [main]> select * from mysql_users;
+----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+
| username | password | active | use_ssl | default_hostgroup | default_schema | schema_locked | transaction_persistent | fast_forward | backend | frontend | max_connections |
+----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+
| proxysql | 123456 | 1 | 0 | 1 | NULL | 0 | 1 | 0 | 1 | 1 | 10000 |
+----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+
1 row in set (0.00 sec)
在mysql上添加监控的用户
mysql> GRANT SELECT ON *.* TO 'monitor'@'192.168.22.%' IDENTIFIED BY 'monitor';
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
#在proxysql主机端配置监控用户
MySQL [main]> set mysql-monitor_username='monitor';
Query OK, 1 row affected (0.00 sec)
MySQL [main]> set mysql-monitor_password='monitor';
Query OK, 1 row affected (0.00 sec)
#参考文章：https://github.com/sysown/proxysql/wiki/ProxySQL-Configuration
10、配置proxysql的转发规则
MySQL [main]> insert into mysql_query_rules(rule_id,active,match_digest,destination_hostgroup,apply)values(1,1,'^SELECT.*FOR UPDATE$',1,1);
Query OK, 1 row affected (0.01 sec)
MySQL [main]> insert into mysql_query_rules(rule_id,active,match_digest,destination_hostgroup,apply)values(2,1,'^SELECT',2,1);
Query OK, 1 row affected (0.00 sec)
MySQL [main]> 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$ | 1 | 1 |
| 2 | 1 | ^SELECT | 2 | 1 |
+---------+--------+----------------------+-----------------------+-------+
2 rows in set (0.00 sec)
#配置查询select的请求转发到hostgroup_id=2组上（读组）
#征对select * from table_name for update这样的修改语句，我们是需要将请求转到写组，也就是hostgroup_id=1
#对于其它没有被规则匹配的请求全部转发到默认的组（mysql_users表中default_hostgroup）
11、更新配置到RUNTIME中
由上面的配置系统层级关系可以得知所有进来的请求首先是经过RUNTIME层
MySQL [main]> load mysql users to runtime;
Query OK, 0 rows affected (0.00 sec)
MySQL [main]> load mysql servers to runtime;
Query OK, 0 rows affected (0.02 sec)
MySQL [main]> load mysql query rules to runtime;
Query OK, 0 rows affected (0.00 sec)
MySQL [main]> load mysql variables to runtime;
Query OK, 0 rows affected (0.00 sec)
MySQL [main]> load admin variables to runtime;
Query OK, 0 rows affected (0.00 sec)
12、将所有配置保存至磁盘上
所有配置数据保存到磁盘上，也就是永久写入/var/lib/proxysql/proxysql.db这个文件中
MySQL [main]> save mysql users to disk;
Query OK, 0 rows affected (0.03 sec)
MySQL [main]> save mysql servers to disk;
Query OK, 0 rows affected (0.04 sec)
MySQL [main]> save mysql query rules to disk;
Query OK, 0 rows affected (0.03 sec)
MySQL [main]> save mysql variables to disk;
Query OK, 94 rows affected (0.02 sec)
MySQL [main]> save admin variables to disk;
Query OK, 31 rows affected (0.02 sec)
MySQL [main]> load mysql users to runtime;
Query OK, 0 rows affected (0.00 sec)
13、测试读写分离
[root@proxy ~]# mysql -uproxysql -p123456 -h 127.0.0.1 -P 6033
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.5.30 (ProxySQL)
Copyright (c) 2000, 2017, 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 |
| sys |
| testdb |
+--------------------+
5 rows in set (0.02 sec)
#这才是我们真正的数据库啊
创建数据与表，测试读写分离情况
MySQL [(none)]> create database test_proxysql;
Query OK, 1 row affected (0.02 sec)
MySQL [(none)]> use test_proxysql;
Database changed
MySQL [test_proxysql]> create table test_tables(name varchar(20),age int(4));
Query OK, 0 rows affected (0.07 sec)
MySQL [test_proxysql]> insert into test_tables values('zhao','30');
Query OK, 1 row affected (0.09 sec)
MySQL [test_proxysql]> select * from test_tables;
+------+------+
| name | age |
+------+------+
| zhao | 30 |
+------+------+
1 row in set (0.02 sec)
在proxysql管理端查看读写分离
MySQL [main]> select * from stats_mysql_query_digest;
+-----------+--------------------+----------+--------------------+------------------------------------------------------+------------+------------+------------+----------+----------+----------+
| hostgroup | schemaname | username | digest | digest_text | count_star | first_seen | last_seen | sum_time | min_time | max_time |
+-----------+--------------------+----------+--------------------+------------------------------------------------------+------------+------------+------------+----------+----------+----------+
| 2 | test_proxysql | proxysql | 0x57CF7EC26C91DF9A | select * from test_tables | 1 | 1527667635 | 1527667635 | 14253 | 14253 | 14253 |
| 1 | information_schema | proxysql | 0x226CD90D52A2BA0B | select @@version_comment limit ? | 1 | 1527667214 | 1527667214 | 0 | 0 | 0 |
| 1 | test_proxysql | proxysql | 0xFF9877421CFBDA6F | insert into test_tables values(?,?) | 1 | 1527667623 | 1527667623 | 89033 | 89033 | 89033 |
| 1 | information_schema | proxysql | 0xE662AE2DEE853B44 | create database test-proxysql | 1 | 1527667316 | 1527667316 | 8470 | 8470 | 8470 |
| 1 | information_schema | proxysql | 0x02033E45904D3DF0 | show databases | 1 | 1527667222 | 1527667222 | 19414 | 19414 | 19414 |
| 1 | information_schema | proxysql | 0xB9EF28C84E4207EC | create database test_proxysql | 1 | 1527667332 | 1527667332 | 15814 | 15814 | 15814 |
| 2 | information_schema | proxysql | 0x620B328FE9D6D71A | SELECT DATABASE() | 1 | 1527667342 | 1527667342 | 23386 | 23386 | 23386 |
| 1 | test_proxysql | proxysql | 0x02033E45904D3DF0 | show databases | 1 | 1527667342 | 1527667342 | 2451 | 2451 | 2451 |
| 1 | test_proxysql | proxysql | 0x59F02DA280268525 | create table test_tables | 1 | 1527667360 | 1527667360 | 9187 | 9187 | 9187 |
| 1 | test_proxysql | proxysql | 0x99531AEFF718C501 | show tables | 1 | 1527667342 | 1527667342 | 1001 | 1001 | 1001 |
| 1 | test_proxysql | proxysql | 0xC745E37AAF6095AF | create table test_tables(name varchar(?),age int(?)) | 1 | 1527667558 | 1527667558 | 68935 | 68935 | 68935 |
+-----------+--------------------+----------+--------------------+------------------------------------------------------+------------+------------+------------+----------+----------+----------+
11 rows in set (0.01 sec)
#从上述结果就可以看出读写分离配置是成功的，读请求是转发到2组，写请求转发到1组
整个读写分离的架构配置到此就完成了，但是此架构存在需要优化的地方，那就是此架构存在单点问题。实际生产环境中可采用MHA+ProxySQL+Mysql这类架构解决此问题，请持续关注【民工哥技术之路】公众号，后续输出相关的架构实战。
关于Mysql各类高可用架构可阅读前面的文章
浅谈MySQL集群高可用架构
MySQL集群高可用架构之MHA
Mysql+Mycat实现数据库主从同步与读写分离
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