使用MyCAT代理MySQL數據庫

環境中需要使用統一入口訪問多數據庫，環境下有B2C、B2B、O2O數據庫，現針對所有B2C、B2B、O2O中的所有訂單進行聚合搭建一個類似京東京享值一樣的會員級別系統，針對不同級別會員給予不同的優惠。

數據庫	數據庫主機	數據庫用戶名	數據庫用密碼	備註
b2c	192.168.0.200	root	123456	B2C數據庫
b2b	192.168.0.201	root	123456	B2B數據庫
o2o	192.168.0.202	root	123456	O2O數據庫

1.先安裝JDK
tar zxf jdk-8u211-linux-x64.tar.gz
mv jdk1.8.0_211 /usr/local/

2.配置PATH
echo 'export PATH=/usr/local/jdk1.8.0_211/bin:$PATH'>>/etc/profile
source /etc/profile
java -version

3.下載mycat
wget http://dl.mycat.io/1.6.6.1/Mycat-server-1.6.6.1-release-20181031195535-linux.tar.gz
mv mycat /usr/local/

4.配置mycat
配置server.xml
cd /usr/local/mycat
cp -rf conf conf_ori
cd conf
vim server.xml

 <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mycat:server SYSTEM "server.dtd">
<mycat:server xmlns:mycat="http://io.mycat/">
        <system>
        <property name="nonePasswordLogin">0</property>
        <property name="useHandshakeV10">1</property>
        <property name="useSqlStat">0</property>
        <property name="useGlobleTableCheck">0</property>
                <property name="sequnceHandlerType">2</property>
        <property name="subqueryRelationshipCheck">false</property>
                <property name="processorBufferPoolType">0</property>
                <property name="handleDistributedTransactions">0</property>
                <property name="useOffHeapForMerge">1</property>
        <property name="memoryPageSize">64k</property>
                <property name="spillsFileBufferSize">1k</property>
                <property name="useStreamOutput">0</property>
                <property name="systemReserveMemorySize">384m</property>
                <property name="useZKSwitch">false</property>
                <property name="strictTxIsolation">false</property>
                <property name="useZKSwitch">true</property>
        </system>
        <user name="root" defaultAccount="true">
                <property name="password">123456</property>
                <property name="schemas">b2c,b2b,o2o</property>
        </user>

        <user name="user">
                <property name="password">user</property>
                <property name="schemas">b2c,b2b,o2o</property>
                <property name="readOnly">false</property>
        </user>

</mycat:server>

vim schema.xml

<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://io.mycat/">
        <schema name="b2c" checkSQLschema="false" sqlMaxLimit="100" dataNode="b2c" >
        </schema>
        <schema name="b2b" checkSQLschema="false" sqlMaxLimit="100" dataNode="b2b" >
        </schema>
        <schema name="o2o" checkSQLschema="false" sqlMaxLimit="100" dataNode="o2o" >
        </schema>
        <dataNode name="b2c" dataHost="b2chost" database="b2c" />
        <dataNode name="b2b" dataHost="b2bhost" database="b2b" />
        <dataNode name="o2o" dataHost="o2ohost" database="o2o" />
        <dataHost name="b2chost" maxCon="1000" minCon="10" balance="0" writeType="0" dbType="mysql" dbDriver="native" switchType="1"  slaveThreshold="100">
                <heartbeat>select user()</heartbeat>
                <writeHost host="3310" url="192.168.0.200:3306" user="root" password="123456">
                </writeHost>
        </dataHost>
        <dataHost name="b2bhost" maxCon="1000" minCon="10" balance="0" writeType="0" dbType="mysql" dbDriver="native" switchType="1"  slaveThreshold="100">
                <heartbeat>select user()</heartbeat>
                <writeHost host="3311" url="192.168.0.201:3306" user="root" password="123456">
                </writeHost>
        </dataHost>
        <dataHost name="o2ohost" maxCon="1000" minCon="10" balance="0" writeType="0" dbType="mysql" dbDriver="native" switchType="1"  slaveThreshold="100">
                <heartbeat>select user()</heartbeat>
                <writeHost host="3312" url="192.168.0.202:3306" user="root" password="123456">
                </writeHost>
        </dataHost>
</mycat:schema>

可以看到關鍵的邏輯是這個schema.xml配置文件

5.啓動mycat並查看日誌
啓動mycat
/usr/local/mycat/bin/mycat start
查看日誌
vim /usr/local/mycat/logs/wrapper.log
顯示

STATUS | wrapper  | 2019/05/26 18:28:10 | --> Wrapper Started as Daemon
STATUS | wrapper  | 2019/05/26 18:28:10 | Launching a JVM...
INFO   | jvm 1    | 2019/05/26 18:28:10 | Java HotSpot(TM) 64-Bit Server VM warning: ignoring option MaxPermSize=64M; support was removed in 8.0
INFO   | jvm 1    | 2019/05/26 18:28:11 | Wrapper (Version 3.2.3) http://wrapper.tanukisoftware.org
INFO   | jvm 1    | 2019/05/26 18:28:11 |   Copyright 1999-2006 Tanuki Software, Inc.  All Rights Reserved.
INFO   | jvm 1    | 2019/05/26 18:28:11 |
INFO   | jvm 1    | 2019/05/26 18:28:12 | MyCAT Server startup successfully. see logs in logs/mycat.log

可以看到服務啓動了

6.查看結果
mysql -h127.0.0.1 -P8066 -uroot -p123456

Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.29-mycat-1.6.6.1-release-20181031195535 MyCat Server (OpenCloudDB)

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;
+----------+
| DATABASE |
+----------+
| b2b      |
| o2o      |
| b2c    |
+----------+
3 rows in set (0.00 sec)