ProxySQL+Mysql實現資料庫讀寫分離實戰
阿新 • • 發佈：2020-11-27
ProxySQL+Mysql實現資料庫讀寫分離實戰
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#MySQL從入門到放棄
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ProxySQL介紹
ProxySQL是一個高效能的MySQL中介軟體，擁有強大的規則引擎。具有以下特性：
1、連線池，而且是multiplexing
2、主機和使用者的最大連線數限制
3、自動下線後端DB
延遲超過閥值
ping 延遲超過閥值
網路不通或宕機
4、強大的規則路由引擎
實現讀寫分離
查詢重寫
sql流量映象
5、支援prepared statement
6、支援Query Cache
7、支援負載均衡，與gelera結合自動failover
整體環境介紹
1、系統環境
三臺伺服器系統環境一致如下
[root@db1 ~]# cat /etc/redhat-release
CentOS Linux release 7.4.1708 (Core)
[root@db1 ~]# uname -r
3.10.0-693.el7.x86_642、IP地址與軟體版本
- 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、關閉防火牆、selinuxsystemctl stop firewalld #停止防火牆服務 systemctl disable firewalld #禁止開機自啟動 sed -i 's#SELINUX=enforcing#SELINUX=disabled#g' /etc/selinux/conf && reboot #用sed命令替換的試修改selinux的配置檔案4、mysql安裝與主從同步
安裝請參考以下文章
LAMP架構應用實戰——MySQL服務
主從同步請參以下文章
Linux系統MySQL資料庫主從同步實戰過程
安裝佈署過程
1、資料庫主從同步
檢視主從同步狀態
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)
檢測主從同步
[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上檢視是否同步
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| testdb |
+--------------------+
5 rows in set (0.01 sec)2、準備proxySQL軟體
[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.rpm3、安裝配置
[root@proxy ~]# yum install -y proxysql-1.4.8-1-centos7.x86_64.rpm
[root@proxy ~]# rpm -ql proxysql
/etc/init.d/proxysql #啟動指令碼
/etc/proxysql.cnf #配置檔案，僅在第一次(/var/lib/proxysql/proxysql.db檔案不存在)啟動時有效。啟#動後可以在proxysql管理端中通過修改資料庫的方式修改配置並生效(官方推薦方式。)
/usr/bin/proxysql #主程式檔案
/usr/share/proxysql/tools/proxysql_galera_checker.sh
/usr/share/proxysql/tools/proxysql_galera_writer.pl4、配置檔案詳解
[root@proxy ~]# egrep -v "^#|^$" /etc/proxysql.cnf
datadir="/var/lib/proxysql" #資料目錄
admin_variables=
{
admin_credentials="admin:admin" #連線管理端的使用者名稱與密碼
mysql_ifaces="0.0.0.0:6032" #管理埠，用來連線proxysql的管理資料庫
}
mysql_variables=
{
threads=4 #指定轉發埠開啟的執行緒數量
max_connections=2048
default_query_delay=0
default_query_timeout=36000000
have_compress=true
poll_timeout=2000
interfaces="0.0.0.0:6033" #指定轉發埠，用於連線後端mysql資料庫的，相當於代理作用
default_schema="information_schema"
stacksize=1048576
server_version="5.5.30" #指定後端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=
(
)
#因此我們使用官方推薦的方式來配置proxy sql5、啟動服務並檢視
[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))
#可以看出轉發埠6033是啟動了四個執行緒6、在mysql上配置賬號並授權
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預設資料庫說明
[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：記憶體配置資料庫，表裡存放後端db例項、使用者驗證、路由規則等資訊。表名以 runtime開頭的表示proxysql當前執行的配置內容，不能通過dml語句修改，只能修改對應的不以 runtime 開頭的（在記憶體）裡的表，然後 LOAD 使其生效， SAVE 使其存到硬碟以供下次重啟載入。
disk：是持久化到硬碟的配置，sqlite資料檔案。
stats：是proxysql執行抓取的統計資訊，包括到後端各命令的執行次數、流量、processlist、查詢種類彙總/執行時間等等。
monitor：庫儲存 monitor 模組收集的資訊，主要是對後端db的健康/延遲檢查。
8、proxysql的配置系統
ProxySQL具有一個複雜但易於使用的配置系統，可以滿足以下需求：
1、允許輕鬆動態更新配置（這是為了讓ProxySQL使用者可以在需要零宕機時間配置的大型基礎架構中使用它）。與MySQL相容的管理介面可用於此目的。
2、允許儘可能多的配置專案動態修改，而不需要重新啟動ProxySQL程序
3、可以毫不費力地回滾無效配置
4、這是通過多級配置系統實現的，其中設定從執行時移到記憶體，並根據需要持久儲存到磁碟。
3級配置由以下幾層組成：
+-------------------------+
| RUNTIME |
+-------------------------+
/|\ |
| |
[1] | [2] |
| \|/
+-------------------------+
| MEMORY |
+-------------------------+ _
/|\ | |\
| | \
[3] | [4] | \ [5]
| \|/ \
+-------------------------+ +-------------------------+
| DISK | | CONFIG FILE |
+-------------------------+ +-------------------------+
參考文章：https://github.com/sysown/proxysql/wiki/Configuring-ProxySQL9、配置proxysql管理使用者
proxysql預設的表資訊如下
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)
#這裡是使用insert into語句來動態配置，而可以不需要重啟
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)
#接下來將剛剛在mysql客戶端建立的使用者寫入到proxy sql主機的mysql_users表中，它也是用於proxysql客戶端訪問資料庫，預設組是寫組，當讀寫分離規則出現問題時，它會直接訪問預設組的資料庫。
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上新增監控的使用者
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主機端配置監控使用者
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)
#參考文章：https://github.com/sysown/proxysql/wiki/ProxySQL-Configuration10、配置proxysql的轉發規則
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)
#配置查詢select的請求轉發到hostgroup_id=2組上（讀組）
#徵對select * from table_name for update這樣的修改語句，我們是需要將請求轉到寫組，也就是hostgroup_id=1
#對於其它沒有被規則匹配的請求全部轉發到預設的組（mysql_users表中default_hostgroup）11、更新配置到RUNTIME中
由上面的配置系統層級關係可以得知所有進來的請求首先是經過RUNTIME層
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、將所有配置儲存至磁碟上
所有配置資料儲存到磁碟上，也就是永久寫入/var/lib/proxysql/proxysql.db這個檔案中
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、測試讀寫分離
[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)
#這才是我們真正的資料庫啊建立資料與表，測試讀寫分離情況
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管理端檢視讀寫分離
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)
#從上述結果就可以看出讀寫分離配置是成功的，讀請求是轉發到2組，寫請求轉發到1組
整個讀寫分離的架構配置到此就完成了，但是此架構存在需要優化的地方，那就是此架構存在單點問題。實際生產環境中可採用MHA+ProxySQL+Mysql這類架構解決此問題，請持續關注【民工哥Linux運維】公眾號，後續輸出相關的架構實戰。
關於Mysql各類高可用架構可閱讀前面的文章
