Mariadb之主从复制的读写分离
在mariadb的主从复制集群中，读的能力被扩展了，而写的能力始终没有被扩展；这样一来对于主服务器就存在单点的问题，通常除了做双主可解决主节点单点的问题，我们还可以给主节点做高可用；而对于mariadb的主从复制集群来讲，虽然读的能力提升了，但通常情况后端数据库服务器是直接面向程序，这意味着程序要知道读请求和写请求该发往不同的数据库服务器上；在用户发来读请求，这个程序它会分析用户的请求，然后把用户的请求代理到后端server上；也就是说我们需要一个程序能够解析用户的读写操作，把对应的操作代理到后端不同的节点上；这样一来用户的读操作始终均衡的被调度到从节点，写操作调度到主节点；
首先我们来回顾下代理的概念，所谓代理就是指的是一端面向客户端，另外一端面向服务端，代理客户端访问服务端，我们把这种代理叫正向代理；代理服务端响应客户端我们叫做反向代理，这个我们在之前nginx系列博客中阐述过这样的概念；不管是正向代理还是反向代理他们都是代理，他们都有一个共同点就是代表一端（客户端/服务端）访问或响应另一端；简单讲代理就是即充当服务端角色又充当客户端角色；在mariadb的主从复制集群中，读的能力被扩展了，而写的能力始终没有被扩展；这样一来对于主服务器就存在单点的问题，通常除了做双主可解决主节点单点的问题，我们还可以给主节点做高可用；而对于mariadb的主从复制集群来讲，虽然读的能力提升了，但通常情况后端数据库服务器是直接面向程序，这意味着程序要知道读请求和写请求该发往不同的数据库服务器上；在用户发来读请求，这个程序它会分析用户的请求，然后把用户的请求代理到后端server上；也就是说我们需要一个程序能够解析用户的读写操作，把对应的操作代理到后端不同的节点上；这样一来用户的读操作始终均衡的被调度到从节点，写操作调度到主节点；proxysql这款软件就有我们上面说的功能，它能够将用户发来的读写操作，通过proxysql的语句路由，把对应请求分别发送到不同节点执行；如下图所示：
从上面的图片可以看到，proxysql就是一代理，面向程序它就是一数据库服务器，程序把读操作和写操作都发送给它，然后proxysql通过我们定义的路由规则，把对应语句再代理到不同的后端主从架构节点上执行；接下来我们来看看proxysql的配置和使用吧；以下实验室基于mariadb的主从复制集群上做的，有关主从复制的配置请参考https://www.cnblogs.com/qiuhom-1874/tag/mariadb%E4%B8%BB%E4%BB%8E%E5%A4%8D%E5%88%B6/；
1、安装proxysql(添加yum源，直接用yum安装)
2、查看proxysql的简介
[root@lxc ~]# yum info proxysql Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * base: mirrors.aliyun.com * extras: mirrors.aliyun.com * updates: mirrors.aliyun.com Available Packages Name : proxysql Arch : x86_64 Version : 2.0.12 Release : 1 Size : 9.8 M Repo : proxysql_repo/7 Summary : A high-performance MySQL proxy URL : https://proxysql.com/ License : GPL+ Description : A high-performance MySQL proxy [root@lxc ~]#
提示：如果添加了yum直接yum info proxysql能够看到以上信息，表示我们添加到yum源已经生效；
3、安装proxysql
[root@lxc ~]# yum install proxysql Loaded plugins: fastestmirror proxysql_repo | 2.9 kB 00:00:00 Loading mirror speeds from cached hostfile * base: mirrors.aliyun.com * extras: mirrors.aliyun.com * updates: mirrors.aliyun.com Resolving Dependencies --> Running transaction check ---> Package proxysql.x86_64 0:2.0.12-1 will be installed --> Processing Dependency: libgnutls.so.28(GNUTLS_3_1_0)(64bit) for package: proxysql-2.0.12-1.x86_64 --> Processing Dependency: libgnutls.so.28(GNUTLS_3_0_0)(64bit) for package: proxysql-2.0.12-1.x86_64 --> Processing Dependency: gnutls for package: proxysql-2.0.12-1.x86_64 --> Processing Dependency: libgnutls.so.28(GNUTLS_1_4)(64bit) for package: proxysql-2.0.12-1.x86_64 --> Processing Dependency: libgnutls.so.28()(64bit) for package: proxysql-2.0.12-1.x86_64 --> Running transaction check ---> Package gnutls.x86_64 0:3.3.29-9.el7_6 will be installed --> Processing Dependency: trousers >= 0.3.11.2 for package: gnutls-3.3.29-9.el7_6.x86_64 --> Processing Dependency: libnettle.so.4()(64bit) for package: gnutls-3.3.29-9.el7_6.x86_64 --> Processing Dependency: libhogweed.so.2()(64bit) for package: gnutls-3.3.29-9.el7_6.x86_64 --> Running transaction check ---> Package nettle.x86_64 0:2.7.1-8.el7 will be installed ---> Package trousers.x86_64 0:0.3.14-2.el7 will be installed --> Finished Dependency Resolution Dependencies Resolved ===================================================================================================================================================================== Package Arch Version Repository Size ===================================================================================================================================================================== Installing: proxysql x86_64 2.0.12-1 proxysql_repo 9.8 M Installing for dependencies: gnutls x86_64 3.3.29-9.el7_6 base 680 k nettle x86_64 2.7.1-8.el7 base 327 k trousers x86_64 0.3.14-2.el7 base 289 k Transaction Summary ===================================================================================================================================================================== Install 1 Package (+3 Dependent packages) Total download size: 11 M Installed size: 41 M Is this ok [y/d/N]: y Downloading packages: (1/4): gnutls-3.3.29-9.el7_6.x86_64.rpm | 680 kB 00:00:00 (2/4): nettle-2.7.1-8.el7.x86_64.rpm | 327 kB 00:00:00 (3/4): trousers-0.3.14-2.el7.x86_64.rpm | 289 kB 00:00:00 warning: /var/cache/yum/x86_64/7/proxysql_repo/packages/proxysql-2.0.12-1-centos7.x86_64.rpm: Header V4 RSA/SHA256 Signature, key ID 79953b49: NOKEYMB 00:00:04 ETA Public key for proxysql-2.0.12-1-centos7.x86_64.rpm is not installed (4/4): proxysql-2.0.12-1-centos7.x86_64.rpm | 9.8 MB 00:28:05 --------------------------------------------------------------------------------------------------------------------------------------------------------------------- Total 6.7 kB/s | 11 MB 00:28:05 Retrieving key from https://repo.proxysql.com/ProxySQL/repo_pub_key Importing GPG key 0x79953B49: Userid : "rene cannnao (Proxysql Repository) <rene.cannao@gmail.com>" Fingerprint: 1448 bf69 3ca6 00c7 99eb 9358 04a5 62fb 7995 3b49 From : https://repo.proxysql.com/ProxySQL/repo_pub_key Is this ok [y/N]: y Running transaction check Running transaction test Transaction test succeeded Running transaction Installing : trousers-0.3.14-2.el7.x86_64 1/4 Installing : nettle-2.7.1-8.el7.x86_64 2/4 Installing : gnutls-3.3.29-9.el7_6.x86_64 3/4 Installing : proxysql-2.0.12-1.x86_64 4/4 warning: group proxysql does not exist - using root warning: group proxysql does not exist - using root Created symlink from /etc/systemd/system/multi-user.target.wants/proxysql.service to /etc/systemd/system/proxysql.service. Verifying : gnutls-3.3.29-9.el7_6.x86_64 1/4 Verifying : proxysql-2.0.12-1.x86_64 2/4 Verifying : nettle-2.7.1-8.el7.x86_64 3/4 Verifying : trousers-0.3.14-2.el7.x86_64 4/4 Installed: proxysql.x86_64 0:2.0.12-1 Dependency Installed: gnutls.x86_64 0:3.3.29-9.el7_6 nettle.x86_64 0:2.7.1-8.el7 trousers.x86_64 0:0.3.14-2.el7 Complete! [root@lxc ~]#
提示：除此以上方式安装proxysql，当然也可以直接使用wget 去github上的项目地址下载
[root@lxc ~]# wget https://github.com/sysown/proxysql/releases/download/v2.0.12/proxysql-2.0.12-1-centos7.x86_64.rpm
提示：下载好proxysql 包后，然后通过yum直接安装即可；推荐使用yum来安装下载好的包，它可以解决依赖关系，不推荐使用rpm 安装；
4、查看proxysql包安装的文件列表
[root@lxc ~]# rpm -ql proxysql /etc/logrotate.d/proxysql /etc/proxysql.cnf /etc/systemd/system/proxysql-initial.service /etc/systemd/system/proxysql.service /usr/bin/proxysql /usr/share/proxysql/tools/proxysql_galera_checker.sh /usr/share/proxysql/tools/proxysql_galera_writer.pl [root@lxc ~]#
提示：从上面的信息可以看到proxysql的配置文件是/etc/proxysql.cnf,二进制文件是/usr/bin/proxysql，unit file是/etc/systemd/system/proxysql.service
5、配置proxysql
[root@lxc ~]# cat /etc/proxysql.cnf
########################################################################################
datadir="/var/lib/proxysql"
errorlog="/var/lib/proxysql/proxysql.log"
admin_variables=
{
admin_credentials="admin:admin"
# mysql_ifaces="127.0.0.1:6032;/tmp/proxysql_admin.sock"
mysql_ifaces="0.0.0.0:6033"
# refresh_interval=2000
# debug=true
}
mysql_variables=
{
threads=4
max_connections=2048
default_query_delay=0
default_query_timeout=36000000
have_compress=true
poll_timeout=2000
# interfaces="0.0.0.0:6033;/tmp/proxysql.sock"
interfaces="0.0.0.0:3306"
default_schema="information_schema"
stacksize=1048576
server_version="5.5.30"
connect_timeout_server=3000
# make sure to configure monitor username and password
# https://github.com/sysown/proxysql/wiki/Global-variables#mysql-monitor_username-mysql-monitor_password
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
}
# defines all the MySQL servers
mysql_servers =
(
{
address = "192.168.0.22" # no default, required . If port is 0 , address is interpred as a Unix Socket Domain
port = 3306 # no default, required . If port is 0 , address is interpred as a Unix Socket Domain
hostgroup = 3 # no default, required
status = "ONLINE" # default: ONLINE
weight = 1 # default: 1
compression = 0 # default: 0
max_replication_lag = 10 # default 0 . If greater than 0 and replication lag passes such threshold, the server is shunned
},
{
address = "192.168.0.23" # no default, required . If port is 0 , address is interpred as a Unix Socket Domain
port = 3306 # no default, required . If port is 0 , address is interpred as a Unix Socket Domain
hostgroup = 4 # no default, required
status = "ONLINE" # default: ONLINE
weight = 1 # default: 1
compression = 0 # default: 0
max_replication_lag = 10 # default 0 . If greater than 0 and replication lag passes such threshold, the server is shunned
}
)
# defines all the MySQL users
mysql_users:
(
{
username = "root" # no default , required
password = "admin123.com" # default: ''
default_hostgroup = 3 # default: 0
active = 1 # default: 1
}
)
#defines MySQL Query Rules
mysql_query_rules:
(
{
rule_id=1
active=1
match_pattern="^SELECT .* FOR UPDATE$"
destination_hostgroup=3
apply=1
},
{
rule_id=2
active=1
match_pattern="^SELECT"
destination_hostgroup=4
apply=1
}
)
mysql_replication_hostgroups=
(
{
writer_hostgroup=3
reader_hostgroup=4
comment="test repl 1"
}
)
[root@lxc ~]#
提示：proxysql配置文件分几个大段，admin_variables这个段里主要配置管理相关变量，比如管理用户名和密码，监听的地址和端口等等；mysql_variables配置proxysql连接后端mysql相关配置，里面有连接后端的server监听的端口，线程数，最大连接数，以及监控相关参数；mysql_servers配置后端mysql/mariadb服务器的地址端口，以及权重，所属组等；mysql_users配置连接后端mysql/mariadb所需的账号和密码以及默认连接到的组；mysql_query_rules配置查询规则，那些语句是写操作，那些语句是读操作；mysql_replication_hostgroups配置写操作对应的组号和读操作对应组号；这里需要注意一点，如果一个配置段中有多个大括号，相互之间用逗号隔离，如果是最后一个大括号需要把后面的逗号去掉；
6、在主从复制节点创建上面配置的账号信息
创建root账号
[root@docker_node01 ~]# mysql Welcome to the MariaDB monitor. Commands end with ; or \g. Your MariaDB connection id is 9 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)]> select user,host,password from mysql.user; +---------+-------------------+-------------------------------------------+ | user | host | password | +---------+-------------------+-------------------------------------------+ | root | localhost | | | root | docker\_node01.io | | | root | 127.0.0.1 | | | root | ::1 | | | rpluser | 192.168.0.% | *4ACFE3202A5FF5CF467898FC58AAB1D615029441 | +---------+-------------------+-------------------------------------------+ 5 rows in set (0.00 sec) MariaDB [(none)]> grant all on *.* to 'root'@'192.168.0.%' identified by 'admin123.com' with grant option; Query OK, 0 rows affected (0.01 sec) MariaDB [(none)]> select user,host,password from mysql.user; +---------+-------------------+-------------------------------------------+ | user | host | password | +---------+-------------------+-------------------------------------------+ | root | localhost | | | root | docker\_node01.io | | | root | 127.0.0.1 | | | root | ::1 | | | rpluser | 192.168.0.% | *4ACFE3202A5FF5CF467898FC58AAB1D615029441 | | root | 192.168.0.% | *2D9AC2437F9E59A51BE8BA89A3D59E76F32F55E8 | +---------+-------------------+-------------------------------------------+ 6 rows in set (0.00 sec) MariaDB [(none)]>
提示：在主节点创建账号会自动同步到从节点，所以从节点可以不用再创建；
创建monitor账号
MariaDB [(none)]> grant all on *.* to 'monitor'@'192.168.0.%' identified by 'monitor' with grant option; Query OK, 0 rows affected (0.01 sec) MariaDB [(none)]> select user,host,password from mysql.user; +---------+-------------------+-------------------------------------------+ | user | host | password | +---------+-------------------+-------------------------------------------+ | root | localhost | | | root | docker\_node01.io | | | root | 127.0.0.1 | | | root | ::1 | | | rpluser | 192.168.0.% | *4ACFE3202A5FF5CF467898FC58AAB1D615029441 | | root | 192.168.0.% | *2D9AC2437F9E59A51BE8BA89A3D59E76F32F55E8 | | monitor | 192.168.0.% | *1975D095AC033CAF4E1BF94F7202A9BBFEEB66F1 | +---------+-------------------+-------------------------------------------+ 7 rows in set (0.00 sec) MariaDB [(none)]>
7、启动proxysql
提示：可以看到我们配置的proxysql管理端监听在6033，启动4个线程来连接后端mariadb服务器，对应的端口都已经处于监听状态了；
8、连接管理端口
[root@lxc ~]# mysql -uadmin -padmin -h192.168.0.21 -P6033 ERROR 1040 (42000): User 'admin' can only connect locally [root@lxc ~]# mysql -uadmin -padmin -h127.0.0.1 -P6033 Welcome to the MariaDB monitor. Commands end with ; or \g. Your MySQL connection id is 7 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 (0.001 sec) MySQL [(none)]>
提示：管理接口默认只能本地连接，但是我们配置管理接口监听在本机所有地址上，所以连接时指定主机地址要使用127.0.0.1才可以，如果使用localhost，它默认会通过sock文件去连接；从上面的结果可以看到，在proxysql上有5个库，其中main库主要存放我们刚才配置相关的表在里面；如下
MySQL [(none)]> use main Reading table information for completion of table and column names You can turn off this feature to get a quicker startup with -A Database changed MySQL [main]> show tables; +----------------------------------------------------+ | tables | +----------------------------------------------------+ | global_variables | | mysql_aws_aurora_hostgroups | | mysql_collations | | mysql_firewall_whitelist_rules | | mysql_firewall_whitelist_sqli_fingerprints | | mysql_firewall_whitelist_users | | mysql_galera_hostgroups | | mysql_group_replication_hostgroups | | mysql_query_rules | | mysql_query_rules_fast_routing | | mysql_replication_hostgroups | | mysql_servers | | mysql_users | | proxysql_servers | | restapi_routes | | runtime_checksums_values | | runtime_global_variables | | runtime_mysql_aws_aurora_hostgroups | | runtime_mysql_firewall_whitelist_rules | | runtime_mysql_firewall_whitelist_sqli_fingerprints | | runtime_mysql_firewall_whitelist_users | | runtime_mysql_galera_hostgroups | | 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_restapi_routes | | runtime_scheduler | | scheduler | +----------------------------------------------------+ 32 rows in set (0.001 sec) MySQL [main]> select * from mysql_servers; +--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment | +--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | 3 | 192.168.0.22 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | | | 4 | 192.168.0.23 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | | +--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ 2 rows in set (0.001 sec) MySQL [main]>
提示：main库中的表以runtime开头的表示当前生效的配置，如果我们要运行时修改配置，我们需要先修改不是runtime开头的表，然后通过load 加载到runtime开头的表中，然后在save存储到文件；
proxysql的多层配置系统
+-------------------------+
| RUNTIME |
+-------------------------+
/|\ |
| |
[1] | [2] |
| \|/
+-------------------------+
| MEMORY |
+-------------------------+ _
/|\ | |\
| | \
[3] | [4] | \ [5]
| \|/ \
+-------------------------+ +-------------------------+
| DISK | | CONFIG FILE |
+-------------------------+ +-------------------------+
提示：从上面的图可以看到proxysql的配置系统分三层，最上面一层是runtime层，该层主要是说通过读取第二层的memory层，而memory主要通过disk或configfile层来获取配置；第一次启动proxysql时，它会从config file层读取配置文件内容到memory层，然后runtime层读取memory层，随后我们就可以通过修改memory层，然后通过load加载到runtime层，或者save存储到disk层；
在各层间移动配置
MySQL user相关操作： LOAD MYSQL USERS FROM MEMORY / LOAD MYSQL USERS TO RUNTIME 将MySQL user从内存数据库加载到运行时数据结构，反之亦然 SAVE MYSQL USERS TO MEMORY / SAVE MYSQL USERS FROM RUNTIME 将MySQL user从运行时持久化到内存数据库 LOAD MYSQL USERS TO MEMORY / LOAD MYSQL USERS FROM DISK 将持久化的MySQL user从磁盘数据库加载到内存数据库 SAVE MYSQL USERS FROM MEMORY / SAVE MYSQL USERS TO DISK 将MySQL user从内存数据库持久化到磁盘数据库 LOAD MYSQL USERS FROM CONFIG 从配置文件中将MySQL user加载到内存数据库中 MySQL server相关操作： LOAD MYSQL SERVERS FROM MEMORY / LOAD MYSQL SERVERS TO RUNTIME 将MySQL server从内存数据库加载到运行时 SAVE MYSQL SERVERS TO MEMORY / SAVE MYSQL SERVERS FROM RUNTIME 将MySQL server从运行时持久化到内存数据库 LOAD MYSQL SERVERS TO MEMORY / LOAD MYSQL SERVERS FROM DISK 将MySQL server从磁盘数据库加载到内存数据库 SAVE MYSQL SERVERS FROM MEMORY / SAVE MYSQL SERVERS TO DISK 将MySQL server从内存数据库持久化到磁盘数据库 LOAD MYSQL SERVERS FROM CONFIG 从配置文件将服务器加载到内存数据库中 MySQL query rules相关操作： LOAD MYSQL QUERY RULES FROM MEMORY / LOAD MYSQL QUERY RULES TO RUNTIME 将MySQL查询规则从内存数据库加载到运行时数据结构 SAVE MYSQL QUERY RULES TO MEMORY / SAVE MYSQL QUERY RULES FROM RUNTIME 将MySQL查询规则从运行时数据结构持久化到内存数据库 LOAD MYSQL QUERY RULES TO MEMORY / LOAD MYSQL QUERY RULES FROM DISK 将MySQL查询规则从磁盘数据库加载到内存数据库 SAVE MYSQL QUERY RULES FROM MEMORY / SAVE MYSQL QUERY RULES TO DISK 将MySQL查询规则从内存数据库持久化到磁盘数据库 LOAD MYSQL QUERY RULES FROM CONFIG 从配置文件查询规则加载到内存数据库中 MySQL variables相关操作： LOAD MYSQL VARIABLES FROM MEMORY / LOAD MYSQL VARIABLES TO RUNTIME 将MySQL变量从内存数据库加载到运行时数据结构 SAVE MYSQL VARIABLES FROM MEMORY / SAVE MYSQL VARIABLES TO DISK 将MySQL变量从内存数据库持久化到磁盘数据库 LOAD MYSQL VARIABLES TO MEMORY / LOAD MYSQL VARIABLES FROM DISK 将MySQL变量从磁盘数据库加载到内存数据库 SAVE MYSQL VARIABLES TO MEMORY / SAVE MYSQL VARIABLES FROM RUNTIME 将MySQL变量从运行时数据结构持久存储到内存数据库中 LOAD MYSQL VARIABLES FROM CONFIG 将配置文件变量加载到内存数据库中 admin variables相关操作： LOAD ADMIN VARIABLES FROM MEMORY / LOAD ADMIN VARIABLES TO RUNTIME 将内存数据库中的管理变量加载到运行时 SAVE ADMIN VARIABLES TO MEMORY / SAVE ADMIN VARIABLES FROM RUNTIME 将管理变量从运行时持久化到内存数据库 LOAD ADMIN VARIABLES TO MEMORY / LOAD ADMIN VARIABLES FROM DISK 将管理变量从磁盘数据库加载到内存数据库 SAVE ADMIN VARIABLES FROM MEMORY / SAVE ADMIN VARIABLES TO DISK 将管理变量从内存数据库持久化到磁盘数据库 LOAD ADMIN VARIABLES FROM CONFIG 将配置文件管理变量加载到内存数据库中 注意：以上命令允许使用以下快捷方式： MEM for MEMORY RUN for RUNTIME 例如，这两个命令是等效的： SAVE ADMIN VARIABLES TO MEMORY SAVE ADMIN VARIABLES TO MEM
提示：以上命令在配置更改加载到RUNTIME之前不会激活任何修改，也就是说只有runtime中的配置生效；
测试：在线增加后端mysql server的地址
[root@lxc ~]# mysql -uadmin -padmin -h127.0.0.1 -P6033 Welcome to the MariaDB monitor. Commands end with ; or \g. Your MySQL connection id is 3 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)]> select * from mysql_servers; +--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment | +--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | 3 | 192.168.0.22 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | | | 4 | 192.168.0.23 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | | +--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ 2 rows in set (0.001 sec) MySQL [(none)]> insert into mysql_servers values (4,'192.168.0.21',3307,0,'ONLINE',1,0,1000,10,0,0,''); Query OK, 1 row affected (0.001 sec) MySQL [(none)]> select * from mysql_servers; +--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment | +--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | 3 | 192.168.0.22 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | | | 4 | 192.168.0.23 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | | | 4 | 192.168.0.21 | 3307 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | | +--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ 3 rows in set (0.001 sec) MySQL [(none)]>
提示：以上操作只在memory层中修改，并未加载到runtime，所以在runtime_mysql_servers表中还是两台后端server
加载mysql server memory层到runtime层
MySQL [(none)]> show tables; +----------------------------------------------------+ | tables | +----------------------------------------------------+ | global_variables | | mysql_aws_aurora_hostgroups | | mysql_collations | | mysql_firewall_whitelist_rules | | mysql_firewall_whitelist_sqli_fingerprints | | mysql_firewall_whitelist_users | | mysql_galera_hostgroups | | mysql_group_replication_hostgroups | | mysql_query_rules | | mysql_query_rules_fast_routing | | mysql_replication_hostgroups | | mysql_servers | | mysql_users | | proxysql_servers | | restapi_routes | | runtime_checksums_values | | runtime_global_variables | | runtime_mysql_aws_aurora_hostgroups | | runtime_mysql_firewall_whitelist_rules | | runtime_mysql_firewall_whitelist_sqli_fingerprints | | runtime_mysql_firewall_whitelist_users | | runtime_mysql_galera_hostgroups | | 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_restapi_routes | | runtime_scheduler | | scheduler | +----------------------------------------------------+ 32 rows in set (0.001 sec) MySQL [(none)]> 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 | +--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | 3 | 192.168.0.22 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | | | 4 | 192.168.0.23 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | | +--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ 2 rows in set (0.006 sec) MySQL [(none)]> select * from mysql_servers; +--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment | +--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | 3 | 192.168.0.22 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | | | 4 | 192.168.0.23 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | | | 4 | 192.168.0.21 | 3307 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | | +--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ 3 rows in set (0.001 sec) MySQL [(none)]> load mysql servers to runtime; Query OK, 0 rows affected (0.015 sec) MySQL [(none)]> 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 | +--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | 3 | 192.168.0.22 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | | | 4 | 192.168.0.21 | 3307 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | | | 4 | 192.168.0.23 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | | +--------------+--------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ 3 rows in set (0.006 sec) MySQL [(none)]>
提示：可以看到执行load操作后，runtime_mysql_servers就加载进去了；此时我们就把memory层的信息加载到runtime层生效了；
验证：通过连接proxysql所在主机的3306端口，执行写操作，看看是否能够同步到其他从节点？
提示：可以看到在proxysql所在主机连接3306线程，是可以连接到主库，因为默认配置连接是到主库，然后在其上创建一个mydb的数据库，也能够及时的同步到其他从库；
测试：读写操作是否分别调度到不同的节点上？
[root@lxc ~]# for i in {1..10} ;do mysql -uroot -padmin123.com -P3306 -h192.168.0.21 -e "select @@server_id" ; done
+-------------+
| @@server_id |
+-------------+
| 2 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 2 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 2 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 3 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 3 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 3 |
+-------------+
[root@lxc ~]# for i in {1..10} ;do mysql -uroot -padmin123.com -P3306 -h192.168.0.21 -e "select @@server_id for update" ; done
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
[root@lxc ~]#
提示：可以看到当执行有写锁时，就立刻把操作调度到server_id=1的主库上去操作；读操作是随机调度到各个节点上进行处理；
作者：Linux-1874
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