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MyCat的介绍与安装以及基本使用
MyCat
MyCat概述
Mycat是数据库中间件，连接java应用程序和数据库。
Java程序与数据库紧密关联耦合严重，高访问量高并发对数据库的压力巨大，因此可以引入数据库中间件MyCat解决。
Mycat的官网：
http://www.mycat.org.cn/mycat1.htmlMycat学习指南：
https://www.yuque.com/books/share/0576de75-ffc4-4c34-8586-952ae4636944GitHub地址：
https://github.com/MyCATApache/Mycat-Server特性
核心功能
1.读写分离
Java操作MyCat，Mycat作为数据源访问，根据Java读、写请求分发到主从Mysql上，从而实现了读写分离。
2.数据分片
对数据库垂直拆分（分库）、对表水平拆分（分表）、对数据库垂直与表水平拆分（分库分表）
3.多数据源整合
Java操作MyCat，Mycat作为数据源访问，根据不同业务进行数据源划分，MyCat访问不同的数据源（MySql、MongoDB），从而实现多数据源整合。
原理
Mycat的原理中最重要的一个动词是“拦截”，它拦截用户发送的 SQL 语句，首先对 SQL语句做一些特定的分析：如分片分析、路由分析、读写分离分析、缓存分析等，然后将此 SQL 发往真实数据库，并将返回的结果做适当的处理，最终再返回给用户。
MyCat的基本使用
安装MyCat
下载地址：
http://dl.mycat.org.cn/wget http://dl.mycat.org.cn/1.6.7.6/20220524101549/Mycat-server-1.6.7.6-release-20220524173810-linux.tar.gz- 1
解压mycat
tar -zxvf Mycat-server-1.6.7.6-release-20220524173810-linux.tar.gz- 1
核心配置
1.MYCAT_HOME/conf/schema.xml中定义逻辑库，表、分片节点等内容 2.MYCAT_HOME/conf/rule.xml中定义分片规则 3.MYCAT_HOME/conf/server.xml中定义用户以及系统相关变量，如端口等- 1
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[root@administrator mycat]# ls conf/ autopartition-long.txt dbseq.sql log4j2.xml partition-range-mod.txt sequence_db_conf.properties server.xml zkdownload auto-sharding-long.txt dbseq - utf8mb4.sql migrateTables.properties rule.xml sequence_distributed_conf.properties sharding-by-enum.txt auto-sharding-rang-mod.txt ehcache.xml myid.properties schema.xml sequence_http_conf.properties wrapper.conf cacheservice.properties index_to_charset.properties partition-hash-int.txt sequence_conf.properties sequence_time_conf.properties zkconf- 1
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基本配置
1.修改配置文件
server.xml修改用户信息，由root用户改为mycat用户，与MySQL区分，同时这个账号是连接MyCat的账号
110 <!--<user name="root" defaultAccount="true">--> 110 <user name="mycat" defaultAccount="true"> 111 <property name="password">123456</property> 112 <property name="schemas">TESTDB</property> 113 <property name="defaultSchema">TESTDB</property> 114 <!--No MyCAT Database selected 错误前会尝试使用该schema作为schema，不设置则为null,报错 --> 115 116 <!-- 表级 DML 权限设置 --> 117 <!-- 118 <privileges check="false"> 119 <schema name="TESTDB" dml="0110" > 120 <table name="tb01" dml="0000"></table> 121 <table name="tb02" dml="1111"></table> 122 </schema> 123 </privileges> 124 --> 125 </user>- 1
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2.修改配置文件
schema.xml先备份
schema.xml为schema.xml.backcp schema.xml schema.xml.back- 1
配置
schema.xml<?xml version="1.0"?> <!DOCTYPE mycat:schema SYSTEM "schema.dtd"> <mycat:schema xmlns:mycat="http://io.mycat/"> <!-- 配置逻辑库 --> <schema name="TESTDB" checkSQLschema="true" sqlMaxLimit="100" randomDataNode="dn1"> <!-- 配置逻辑库下的表 --> <table name="mytb" primaryKey="id" dataNode="dn1" ></table> </schema> <!-- 数据节点配置--> <dataNode name="dn1" dataHost="host1" database="mydb" /> <!-- 节点具体配置--> <dataHost name="host1" maxCon="1000" minCon="10" balance="0" writeType="0" dbType="mysql" dbDriver="jdbc" switchType="1" slaveThreshold="100"> <!-- 心跳检测 --> <heartbeat>select user()</heartbeat> <writeHost host="hostM1" url="jdbc:mysql://localhost:3306" user="mycat" password="123456"></writeHost> </dataHost> </mycat:schema>- 1
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启动MyCat
./mycat start 启动 ./mycat stop 停止 ./mycat console 前台运行 ./mycat restart 重启服务 ./mycat pause 暂停 ./mycat status 查看启动状态- 1
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[root@administrator mycat]# bin/mycat console Running Mycat-server... wrapper | --> Wrapper Started as Console wrapper | Launching a JVM... jvm 1 | Wrapper (Version 3.2.3) http://wrapper.tanukisoftware.org jvm 1 | Copyright 1999-2006 Tanuki Software, Inc. All Rights Reserved. jvm 1 | jvm 1 | Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary. jvm 1 | MyCAT Server startup successfully. see logs in logs/mycat.log- 1
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测试验证
MyCat安装、配置完毕后，就可以让应用程序、客户端连接MyCat，通过Mycat操作MySQL，从而实现程序与数据库的解耦。
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9066是MyCat管理窗口的端口，主要用于管理维护Mycatmysql -umycat -p123456 -P 9066 -h IP- 1
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8066是MyCat数据查询的端口，主要用于通过Mycat查询数据mysql -umycat -p123456 -P 8066 -h IP- 1
mysql> show databases; +--------------------+ | Database | +--------------------+ | TESTDB | +--------------------+ 14 rows in set (0.00 sec) mysql> use TESTDB; Database changed mysql> show tables; +----------------+ | Tables_in_mydb | +----------------+ | mytb | +----------------+ 1 row in set (0.01 sec) mysql> select * from mytb; +------+-------+ | id | name | +------+-------+ | 1 | mycat | +------+-------+ 1 row in set (0.00 sec) mysql>- 1
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Mycat的安全设置
标签权限控制
1.user标签
<!-- 应用程序连接中间件逻辑库的用户名 --> <user name="user"> <!-- 应用程序连接中间件逻辑库的密码 --> <property name="password">user</property> <!-- 逻辑库名称 --> <property name="schemas">TESTDB</property> <!-- true:只读；默认false：可读可写 --> <property name="readOnly">true</property> <!-- 默认逻辑库名称 --> <property name="defaultSchema">TESTDB</property> </user>- 1
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2.privileges标签
privileges 标签可以对逻辑库（schema）、表（table）进行精细化的DML权限控制
<user name="mycat" defaultAccount="true"> <property name="password">123456</property> <property name="schemas">TESTDB</property> <property name="defaultSchema">TESTDB</property> <!--No MyCAT Database selected 错误前会尝试使用该schema作为schema，不设置则为null,报错 --> <!-- 表级 DML 权限设置 --> <!-- 是否开启权限检查,默认false --> <privileges check="false"> <schema name="TESTDB" dml="0110" > <table name="tb01" dml="0000"></table> <table name="tb02" dml="1111"></table> </schema> </privileges> --> </user>- 1
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DML权限 增加insert 更新update 查询select 删除select 0000 N N N N 0010 N N Y N 1110 Y Y Y N 1111 Y Y Y Y SQL拦截
firewall标签用来定义防火墙；firewall下whitehost标签用来定义IP白名单 ，blacklist用来定义SQL黑名单。
1.白名单
设置白名单，实现指定的某主机某用户可以访问Mycat
<!-- 全局SQL防火墙设置 --> <firewall> <!--白名单 --> <whitehost> <!--白名单可以使用通配符%或着*--> <!--对于127.0.0.1能以root账户登录--> <host host="1*7.0.0.*" user="root"/> </whitehost> <blacklist check="false"> </blacklist> </firewall>- 1
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2.黑名单
设置黑名单，实现Mycat对具体SQL操作的拦截，如增删改查等操作的拦截。
<!-- 全局SQL防火墙设置 --> <firewall> <!--白名单 --> <whitehost> <!--白名单可以使用通配符%或着*--> <!--对于127.0.0.1能以root账户登录--> <host host="1*7.0.0.*" user="root"/> </whitehost> <!-- 黑名单 --> <blacklist check="true"> <!-- 禁止root用户进行删除操作 --> <property name="deleteAllow">false</property> </blacklist> </firewall>- 1
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配置项 缺省值 描述 selelctAllow true 是否允许执行SELECT语句 deleteAllow true 是否允许执行DELETE语句 updateAllow true 是否允许执行UPDATE语句 insertAllow true 是否允许执行INSERT语句 createTableAllow true 是否允许创建表 setAllow true 是否允许使用set语法 alterTableAllow true 是否允许执行Alter Table语句 dropTableAllow true 是否允许修改表 commitAllow true 是否允许执行commit操作 rollbackAllow true 是否允许执行roll back操作 MyCat的常用管理命令
9066是Mycat的管理端口，登录Mycat管理窗口：mysql -umycat -h127.0.0.1 -P9066 -p1234561.查看所有管理命令
列出59个Mycat的管理命令
mysql> show @@help; +--------------------------------------------------------------+--------------------------------------------+ | STATEMENT | DESCRIPTION | +--------------------------------------------------------------+--------------------------------------------+ | show @@time.current | Report current timestamp | | show @@time.startup | Report startup timestamp | | show @@version | Report Mycat Server version | | show @@server | Report server status | | show @@threadpool | Report threadPool status | | show @@database | Report databases | | show @@datanode | Report dataNodes | | show @@datanode where schema = ? | Report dataNodes | | show @@datasource | Report dataSources | | show @@datasource where dataNode = ? | Report dataSources | | show @@datasource.synstatus | Report datasource data synchronous | | show @@datasource.syndetail where name=? | Report datasource data synchronous detail | | show @@datasource.cluster | Report datasource galary cluster variables | | show @@processor | Report processor status | | show @@command | Report commands status | | show @@connection | Report connection status | | show @@cache | Report system cache usage | | show @@backend | Report backend connection status | | show @@session | Report front session details | | show @@connection.sql | Report connection sql | | show @@sql.execute | Report execute status | | show @@sql.detail where id = ? | Report execute detail status | | show @@sql | Report SQL list | | show @@sql.high | Report Hight Frequency SQL | | show @@sql.slow | Report slow SQL | | show @@sql.resultset | Report BIG RESULTSET SQL | | show @@sql.sum | Report User RW Stat | | show @@sql.sum.user | Report User RW Stat | | show @@sql.sum.table | Report Table RW Stat | | show @@parser | Report parser status | | show @@router | Report router status | | show @@heartbeat | Report heartbeat status | | show @@heartbeat.detail where name=? | Report heartbeat current detail | | show @@slow where schema = ? | Report schema slow sql | | show @@slow where datanode = ? | Report datanode slow sql | | show @@sysparam | Report system param | | show @@syslog limit=? | Report system mycat.log | | show @@white | show mycat white host | | show @@white.set=?,? | set mycat white host,[ip,user] | | show @@directmemory=1 or 2 | show mycat direct memory usage | | show @@check_global -SCHEMA= ? -TABLE=? -retry=? -interval=? | check mycat global table consistency | | switch @@datasource name:index | Switch dataSource | | kill @@connection id1,id2,... | Kill the specified connections | | stop @@heartbeat name:time | Pause dataNode heartbeat | | reload @@config | Reload basic config from file | | reload @@config_all | Reload all config from file | | reload @@route | Reload route config from file | | reload @@user | Reload user config from file | | reload @@sqlslow= | Set Slow SQL Time(ms) | | reload @@user_stat | Reset show @@sql @@sql.sum @@sql.slow | | rollback @@config | Rollback all config from memory | | rollback @@route | Rollback route config from memory | | rollback @@user | Rollback user config from memory | | reload @@sqlstat=open | Open real-time sql stat analyzer | | reload @@sqlstat=close | Close real-time sql stat analyzer | | offline | Change MyCat status to OFF | | online | Change MyCat status to ON | | clear @@slow where schema = ? | Clear slow sql by schema | | clear @@slow where datanode = ? | Clear slow sql by datanode | +--------------------------------------------------------------+--------------------------------------------+ 59 rows in set (0.01 sec)- 1
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2.重新加载配置文件
只能重新加载Mycat常用配置文件，如果修改一些特殊的配置文件，需要重启Mycat
mysql>reload @@config; Query OK, 1 row affected (0.07 sec) Reload config success- 1
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3.查看逻辑库
mysql> show @@databases; +----------+ | DATABASE | +----------+ | TESTDB | +----------+ 1 row in set (0.00 sec)- 1
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4.查看数据节点
mysql> show @@datanode; +------+------------+-------+-------+--------+------+------+---------+------------+----------+---------+---------------+ | NAME | DATHOST | INDEX | TYPE | ACTIVE | IDLE | SIZE | EXECUTE | TOTAL_TIME | MAX_TIME | MAX_SQL | RECOVERY_TIME | +------+------------+-------+-------+--------+------+------+---------+------------+----------+---------+---------------+ | dn1 | host1/mydb | 0 | mysql | 0 | 10 | 1000 | 12 | 0 | 0 | 0 | -1 | | dn2 | host2/mydb | 0 | mysql | 0 | 10 | 1000 | 10 | 0 | 0 | 0 | -1 | +------+------------+-------+-------+--------+------+------+---------+------------+----------+---------+---------------+ 2 rows in set (0.01 sec)- 1
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注意：可以使用
\G进行格式化结果输出mysql> show @@datanode \G *************************** 1. row *************************** NAME: dn1 DATHOST: host1/mydb INDEX: 0 TYPE: mysql ACTIVE: 0 IDLE: 10 SIZE: 1000 EXECUTE: 12 TOTAL_TIME: 0 MAX_TIME: 0 MAX_SQL: 0 RECOVERY_TIME: -1 *************************** 2. row *************************** NAME: dn2 DATHOST: host2/mydb INDEX: 0 TYPE: mysql ACTIVE: 0 IDLE: 10 SIZE: 1000 EXECUTE: 10 TOTAL_TIME: 0 MAX_TIME: 0 MAX_SQL: 0 RECOVERY_TIME: -1 2 rows in set (0.00 sec)- 1
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5.查看逻辑库对应物理库所在的数据节点
查看TESTDB逻辑库对应的物理数据库所在的数据节点
mysql> show @@datanode where schema=TESTDB; +------+------------+-------+-------+--------+------+------+---------+------------+----------+---------+---------------+ | NAME | DATHOST | INDEX | TYPE | ACTIVE | IDLE | SIZE | EXECUTE | TOTAL_TIME | MAX_TIME | MAX_SQL | RECOVERY_TIME | +------+------------+-------+-------+--------+------+------+---------+------------+----------+---------+---------------+ | dn1 | host1/mydb | 0 | mysql | 0 | 10 | 1000 | 12 | 0 | 0 | 0 | -1 | | dn2 | host2/mydb | 0 | mysql | 0 | 10 | 1000 | 10 | 0 | 0 | 0 | -1 | +------+------------+-------+-------+--------+------+------+---------+------------+----------+---------+---------------+ 2 rows in set (0.00 sec)- 1
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6.查看可用数据节点
mysql> show @@heartbeat; +--------+-------+-----------+------+---------+-------+--------+---------+--------------+---------------------+-------+ | NAME | TYPE | HOST | PORT | RS_CODE | RETRY | STATUS | TIMEOUT | EXECUTE_TIME | LAST_ACTIVE_TIME | STOP | +--------+-------+-----------+------+---------+-------+--------+---------+--------------+---------------------+-------+ | hostM1 | mysql | localhost | 3306 | 1 | 0 | idle | 0 | 14,14,14 | 2022-07-19 17:03:09 | false | | hostS1 | mysql | localhost | 3308 | 1 | 0 | idle | 0 | 14,14,14 | 2022-07-19 17:03:09 | false | | hostM2 | mysql | localhost | 3307 | 1 | 0 | idle | 0 | 14,14,14 | 2022-07-19 17:03:09 | false | | hostS2 | mysql | localhost | 3309 | 1 | 0 | idle | 0 | 14,14,14 | 2022-07-19 17:03:09 | false | +--------+-------+-----------+------+---------+-------+--------+---------+--------------+---------------------+-------+ 4 rows in set (0.00 sec)- 1
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RS_CODE值说明：
-1：代表连接出错 0：初始化的状态 1：代表连接后端的MySQL正常 2：代表连接超时- 1
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7.查看连接信息
1.查看上层应用连接Mycat的所有连接信息
mysql> show @@connection; +------------+------+-----------+------+------------+-------+--------+---------+--------+---------+---------------+-------------+------------+---------+------------+ | PROCESSOR | ID | HOST | PORT | LOCAL_PORT | USER | SCHEMA | CHARSET | NET_IN | NET_OUT | ALIVE_TIME(S) | RECV_BUFFER | SEND_QUEUE | txlevel | autocommit | +------------+------+-----------+------+------------+-------+--------+---------+--------+---------+---------------+-------------+------------+---------+------------+ | Processor0 | 3 | 127.0.0.1 | 9066 | 58110 | mycat | NULL | utf8:33 | 483 | 7788 | 246 | 4096 | 0 | | | +------------+------+-----------+------+------------+-------+--------+---------+--------+---------+---------------+-------------+------------+---------+------------+ 1 row in set (0.00 sec)- 1
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可以使用：
kill @@connection ID的方式来杀死连接Mycat的进程mysql> kill @@ connection 3;- 1
2.查看Mycat连接后端数据库的信息
mysql> show @@backend; +------------+------+---------+-----------+------+--------+--------+---------+------+--------+----------+------------+--------+---------+---------+------------+-------------+ | processor | id | mysqlId | host | port | l_port | net_in | net_out | life | closed | borrowed | SEND_QUEUE | schema | charset | txlevel | autocommit | tx_readonly | +------------+------+---------+-----------+------+--------+--------+---------+------+--------+----------+------------+--------+---------+---------+------------+-------------+ | Processor0 | 32 | 0 | localhost | 3309 | 0 | 0 | 0 | 812 | false | false | 0 | | | | | | | Processor0 | 2 | 0 | localhost | 3306 | 0 | 0 | 0 | 1413 | false | false | 0 | | | | | | | Processor0 | 34 | 0 | localhost | 3308 | 0 | 0 | 0 | 512 | false | false | 0 | | | | | | | Processor0 | 4 | 0 | localhost | 3306 | 0 | 0 | 0 | 1413 | false | false | 0 | | | | | | +------------+------+---------+-----------+------+--------+--------+---------+------+--------+----------+------------+--------+---------+---------+------------+-------------+- 1
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8.查看Mycat中的缓存状态
mysql> show @@cache; +-------------------------------------+-------+------+--------+------+------+-------------+----------+ | CACHE | MAX | CUR | ACCESS | HIT | PUT | LAST_ACCESS | LAST_PUT | +-------------------------------------+-------+------+--------+------+------+-------------+----------+ | ER_SQL2PARENTID | 1000 | 0 | 0 | 0 | 0 | 0 | 0 | | SQLRouteCache | 10000 | 0 | 0 | 0 | 0 | 0 | 0 | | TableID2DataNodeCache.TESTDB_ORDERS | 50000 | 0 | 0 | 0 | 0 | 0 | 0 | +-------------------------------------+-------+------+--------+------+------+-------------+----------+ 3 rows in set (0.00 sec)- 1
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各缓存的类型说明：
ER_SQL2PARENTID：缓存ER分片中，表与父表之间的关系 SQLRouteCache：缓存SQL的路由信息 TableID2DataNodeCache.TESTDB_ORDERS：缓存表与表的主键与分片的对应关系。如果主键不为分片键时，为了加快查询的速度，可以缓存主键与分片键的对应关系- 1
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9.查看数据节点所在主机节点
mysql> show @@datasource; +----------+--------+-------+-----------+------+------+--------+------+------+---------+-----------+------------+ | DATANODE | NAME | TYPE | HOST | PORT | W/R | ACTIVE | IDLE | SIZE | EXECUTE | READ_LOAD | WRITE_LOAD | +----------+--------+-------+-----------+------+------+--------+------+------+---------+-----------+------------+ | dn1 | hostM1 | mysql | localhost | 3306 | W | 0 | 10 | 1000 | 12 | 2 | 0 | | dn1 | hostS1 | mysql | localhost | 3308 | R | 0 | 8 | 1000 | 10 | 0 | 0 | | dn2 | hostM2 | mysql | localhost | 3307 | W | 0 | 10 | 1000 | 10 | 0 | 0 | | dn2 | hostS2 | mysql | localhost | 3309 | R | 0 | 8 | 1000 | 8 | 0 | 0 | +----------+--------+-------+-----------+------+------+--------+------+------+---------+-----------+------------+ 4 rows in set (0.00 sec)- 1
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10.总结
上述Mycat命令行操作便是常用于管理Mycat服务，更多命令行操作参考
show @@help命令Mycat命令行管理方式常用于管理单台Mycat服务，如果需要同时管理Mycat集群中的多个Mycat服务，就需要使用Mycat-Web进行管理。
Mycat-Web性能监控
Mycat-Web是Mycat可视化运维的管理和监控平台，帮助Mycat分担统计任务和配置管理任务。
Mycat-Web引入了ZooKeeper作为配置中心，可以管理多个节点。
Mycat-Web主要管理和监控Mycat的流量、连接、活动线程和内存等，具备IP白名单、邮件告警等模块，还可以统计SQL并分析慢SQL和高频SQL等。
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- 原文地址：https://blog.csdn.net/qq_38628046/article/details/125831133
