MYCAT read / write separation configuration

Why use MyCat
         Now with the development of the Internet , The magnitude of the data also supports the exponential growth , from GB To TB To PB. It is also more difficult to operate data , The traditional relational database can not meet the needs of fast query and data insertion . This is the time NoSQL The emergence of a temporary solution to the crisis . It reduces data security , Reduce support for transactions , Reduce support for complex queries , To get performance improvements . however , On some occasions NoSQL Some trade-offs are not enough for use scenarios , For example, some usage scenarios must have transaction and security indicators . This is the time NoSQL It must be unsatisfied , So you still need to use a relational database . How to use relational database to solve the problem of mass storage ？ At this point, we need to do database clustering , In order to improve query performance, the data of a database is distributed to different databases for storage , In response to this problem came ——MyCat

At the same time, read-write separation can also be used , Solve a single problem , Separate the lines , The pressure will not be so great , If one goes down , The other one can continue to run , At the same time, it can also build a read-write separation master-slave , One is responsible for reading , One is responsible for writing , If one goes down , The other one reads and writes , If it's restored , Then use it normally

mycat Read write separation deployment

Move installation package to /data Inside

tar xvf Mycat-server-1.6.6.1-release-20031195535-linux.tar.gz # decompression 

bin --- Startup file

catlet --- It's not what it takes.

conf --- Initial profile , Including read-write separation, etc., are configured here

cd bin ./mycat start start-up mycat After failure

# install java yum install java

netstat -tnlp Check whether it is opened successfully 8066 It's success / You can also use

ps -ef | grep mycat

Get into conf Configure two main files ,schema.xml and server.xml

First configuration schema.xml( In which TESTDB working principle ： Several database connections mycat Then the client also connects mycat, It's mainly about pretending to be a database , Because our development is mainly connected to this fake database , And then distribute it to the real , It's safer )

Connect to database ：mysql -uuser -p -P8066 -h127.0.0.1 password ：user

Read / write separation ：1 Owners 1 From the , When the user reads , The connection is below S, If it is written, it is connected to the above one M, Generally, when this architecture is used, the pressure on the database is relatively high , The database can't handle , There's a bottleneck , Will use read-write separation , Read and write separately , If the pressure is still high , Will be adding a slave , It becomes 2 The desk is responsible for reading ,1 Desk writing , Generally, reading is stressful . So high availability and load balancing can depend on your needs

Check whether the database can execute 1 Lord 2 from

show slave status\G

  To write schema.xml The configuration file

<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://io.mycat/">
        <schema name="gpsdb2020" checkSQLschema="false" sqlMaxLimit="100" dataNode="dn2"></schema>
        <schema name="zhangsan" checkSQLschema="false" sqlMaxLimit="100" dataNode="dn3"></schema>

       <dataNode name="dn2" dataHost="localhost1" database="gpsdb2020" />
       <dataNode name="dn3" dataHost="localhost1" database="zhangsan" />
        <dataHost name="localhost1" maxCon="500" minCon="20" balance="1" writeType="0" dbType="mysql" dbDriver="native" switchType="1"  slaveThreshold="100">
                <heartbeat>select user()</heartbeat>
                <writeHost host="master" url="192.168.174.133:3306" user="rep" password="123456">
                        <readHost host="slave" url="192.168.174.143:3306" user="rep" password="123456" />
                </writeHost>
        </dataHost>
</mycat:schema>

Modify here ：

To configure server.xml

<user name="admin">

                <property name="password">admin</property>

                <property name="schemas">gpsdb2020,zhangsan</property>

        </user>

  Save startup ./mycat stop ./mycat start