MYCAT configuration

<!--schema Used to define mycat The logical library of , surface , Fragmentation rule ,dataNode and dataHost-->
<mycat:schema xmlns:mycat="http://io.mycat/">

    <schema name=" Write the database name here " checkSQLschema="false" sqlMaxLimit="100">
        <!--checkSQLschema Used to check whether the database name . Query by table name , if true, The query is sql It's going to be select * from  Database name . Table name ; if false, be sql by select * from  Table name -->
        <!--sqlMaxLimit Used to implement limit, Even if sql No definition shown limit, After setting this value ,sql The effect is equivalent to limit 100-->
        <table name=" Write the table name here , It's a logical table to slice " primaryKey="id" dataNode=" To work with dataNode Of name Consistent attributes , Here, for example. dn5" subTables=" Table name _$1-100, This represents 100 Slice table , Table name + Underline + Numbers " rule=" Fragment rule name , The rule name is in rule.xml Definition , for example ysgs"/>
    </schema>

    <!-- Entity library related -->
    <dataNode name="dn5" dataHost=" Database instance , And dataHost Of name Consistent attributes , for example localhost4" database=" Entity database name " />

    <!-- Instance connection related -->
    <!--balance Property represents the load balancing policy :
    balance=”0”,  Do not turn on the read-write separation mechanism , All read operations are sent to the currently available writeHost On .
    balance=”1”, All of the readHost And stand by writeHost Participate in select Statement load balancing , To put it simply , When dual master dual slave mode (M1->S1,M2->S2, also M1 And  M2 Prepare for each other ), Under normal circumstances ,M2,S1,S2 All involved select Statement load balancing .
    balance=”2”, All the reading operations are random in writeHost、readhost To distribute .
    balance=”3”, All read requests are randomly distributed to wiriterHost Corresponding readhost perform ,writerHost No pressure to read 
    -->
    <!--dbDriver, Specify the connection to the back-end database Driver, The values currently available are native and JDBC. Use native Words , Because the value is binary mysql agreement , So you can use mysql and maridb. Other types of databases need to use JDBC Drive to support -->
    <!--switchType,-1 Means no automatic switching ;1 The default value is , Automatic switch ;2 be based on mysql Master slave state switching ;3 Based on cluster switching -->
    <dataHost name="localhost4" maxCon=" Specifies the maximum connection for each read-write instance connection pool , for example 1000" minCon=" Specifies the minimum connection for each read-write instance connection pool , for example 10" balance="0"
              writeType="1" dbType=" Database type , for example mysql" dbDriver="native" switchType="1"  slaveThreshold="100">
        <heartbeat>select user()</heartbeat>
        <writeHost host="hostM1" url=" Database connection " user=" user name " password=" password ">
        </writeHost>
    </dataHost>

</mycat:schema>
<!--rule.xml Configuration related -->
<tableRule name="ysgs, This corresponds to the partition rule name written above ">
<rule>
    <columns> Which column name is used as the partition benchmark </columns>
    <algorithm> Fragmentation rule ,murmur For consistency hash,10 See other bloggers' blogs for the rules of segmentation , Link to [https://blog.csdn.net/zxp2624161989/article/details/107230370/](https://blog.csdn.net/zxp2624161989/article/details/107230370/)</algorithm>
</rule>
</tableRule>

<function name="murmur"
          class="io.mycat.route.function.PartitionByMurmurHash">
<property name="seed">0</property><!--  The default is 0 -->
<property name="count">100</property><!--  Number of database nodes to fragment , Must specify , Otherwise, it can't be divided  -->
<property name="virtualBucketTimes">160</property><!--  An actual database node is mapped to so many virtual nodes , The default is 160 times , That is, the number of virtual nodes is the number of physical nodes 160 times  -->
<!-- <property name="weightMapFile">weightMapFile</property>  Weight of nodes , Nodes without weights are 1. With properties Format of documents , From the 0 Start to count-1 That is, the node index is key, Take node weight value as value . Ownership value must be a positive integer , Otherwise, we should 1 Instead of  -->
<!-- <property name="bucketMapPath">/etc/mycat/bucketMapPath</property>
     Used to observe the distribution of physical nodes and virtual nodes during the test , If this property is specified , The virtual node murmur hash The mapping of values to physical nodes is output to this file by line , No default , If you don't specify , You don't export anything  -->
</function>