基于Mycat的MySQL主从读写分离配置详解与示例

1.mycat二进制包安装

tar -zxvf Mycat-server-1.6.5-release-20180122220033-linux.tar.gz
cd mycat
mv mycat /opt/

useradd mycat
chown -R mycat:mycat mycat

2.mysql操作
搭建主库环境
省略......

创建数据库
CREATE DATABASE `integration01` DEFAULT CHARACTER SET utf8 ;

创建物理表

CREATE TABLE `user` (
`id` int(11) NOT NULL AUTO_INCREMENT COMMENT ‘主键‘,
`borrow_nid` varchar(50) DEFAULT NULL COMMENT ‘借款单号‘,
`create_user` varchar(30) DEFAULT ‘admin‘ COMMENT ‘创建人‘,
`create_time` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT ‘创建时间‘,
`update_time` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT ‘更新时间‘,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT=‘合同后签署数据记录表‘;

以此类推，从 user1，user2，user3一直创建到user10。

3.修改配置文件

[root@canal3 conf]# cat schema.xml
<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://io.mycat/">
<schema name="integration01" checkSQLschema="false" sqlMaxLimit="100">
<table name="user" primaryKey="id" autoIncrement="true" dataNode="dn1"></table >
</schema>
<dataNode name="dn1" dataHost="canal3" database="integration01"/>
<dataHost name="canal3" maxCon="1000" minCon="10" balance="3" writeType="0" dbType="mysql" dbDriver="native" switchType="2" slaveThreshold="100">
<heartbeat>show slave status</heartbeat>
<writeHost host="10.40.20.44" url="10.40.20.44:3307" user="root" password="chengce243">
<readHost host="10.40.20.44" url="10.40.20.44:3308" user="root" password="chengce243"/>
</writeHost>
</dataHost>
</mycat:schema>

(1) 设置 balance="1"与writeType="0"
Balance参数设置：
1. balance=“0”, 所有读操作都发送到当前可用的writeHost上。
2. balance=“1”，所有读操作都随机的发送到readHost。
3. balance=“2”，所有读操作都随机的在writeHost、readhost上分发
WriteType参数设置：
1. writeType=“0”, 所有写操作都发送到可用的writeHost上。
2. writeType=“1”，所有写操作都随机的发送到readHost。
3. writeType=“2”，所有写操作都随机的在writeHost、readhost分上发。
“readHost是从属于writeHost的，即意味着它从那个writeHost获取同步数据，因此，当它所属的writeHost宕机了，则它也不会再参与到读写分离中来，即“不工作了”，这是因为此时，它的数据已经“不可靠”了。基于这个考虑，目前mycat 1.3和1.4版本中，若想支持MySQL一主一从的标准配置，并且在主节点宕机的情况下，从节点还能读取数据，则需要在Mycat里配置为两个writeHost并设置banlance=1。”

(2) 设置 switchType="2" 与slaveThreshold="100"
“Mycat心跳检查语句配置为 show slave status ，dataHost 上定义两个新属性： switchType="2" 与slaveThreshold="100"，此时意味着开启MySQL主从复制状态绑定的读写分离与切换机制。Mycat心跳机制通过检测 show slave status 中的 "Seconds_Behind_Master", "Slave_IO_Running", "Slave_SQL_Running" 三个字段来确定当前主从同步的状态以及Seconds_Behind_Master主从复制时延。“

[root@canal3 conf]# cat server.xml
<?xml version="1.0" encoding="UTF-8"?>
<!-- - - Licensed under the Apache License, Version 2.0 (the "License");
- you may not use this file except in compliance with the License. - You
may obtain a copy of the License at - - http://www.apache.org/licenses/LICENSE-2.0
- - Unless required by applicable law or agreed to in writing, software -
distributed under the License is distributed on an "AS IS" BASIS, - WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - See the
License for the specific language governing permissions and - limitations
under the License. -->
<!DOCTYPE mycat:server SYSTEM "server.dtd">
<mycat:server xmlns:mycat="http://io.mycat/">
<system>
<property name="nonePasswordLogin">0</property> <!-- 0为需要密码登陆、1为不需要密码登陆 ,默认为0，设置为1则需要指定默认账户-->
<property name="useHandshakeV10">1</property>
<property name="useSqlStat">0</property> <!-- 1为开启实时统计、0为关闭 -->
<property name="useGlobleTableCheck">0</property> <!-- 1为开启全加班一致性检测、0为关闭 -->

<property name="sequnceHandlerType">2</property>
<property name="subqueryRelationshipCheck">false</property> <!-- 子查询中存在关联查询的情况下,检查关联字段中是否有分片字段 .默认 false -->
<!-- <property name="useCompression">1</property>--> <!--1为开启mysql压缩协议-->
<!-- <property name="fakeMySQLVersion">5.6.20</property>--> <!--设置模拟的MySQL版本号-->
<!-- <property name="processorBufferChunk">40960</property> -->
<!--
<property name="processors">1</property>
<property name="processorExecutor">32</property>
-->
<!--默认为type 0: DirectByteBufferPool | type 1 ByteBufferArena | type 2 NettyBufferPool -->
<property name="processorBufferPoolType">0</property>
<!--默认是65535 64K 用于sql解析时最大文本长度 -->
<!--<property name="maxStringLiteralLength">65535</property>-->
<!--<property name="sequnceHandlerType">0</property>-->
<!--<property name="backSocketNoDelay">1</property>-->
<!--<property name="frontSocketNoDelay">1</property>-->
<!--<property name="processorExecutor">16</property>-->
<!--
<property name="serverPort">8066</property> <property name="managerPort">9066</property>
<property name="idleTimeout">300000</property> <property name="bindIp">0.0.0.0</property>
<property name="frontWriteQueueSize">4096</property> <property name="processors">32</property> -->
<!--分布式事务开关，0为不过滤分布式事务，1为过滤分布式事务（如果分布式事务内只涉及全局表，则不过滤），2为不过滤分布式事务,但是记录分布式事务日志-->
<property name="handleDistributedTransactions">0</property>

<!--
off heap for merge/order/group/limit 1开启 0关闭
-->
<property name="useOffHeapForMerge">1</property>

<!--
单位为m
-->
<property name="memoryPageSize">64k</property>

<!--
单位为k
-->
<property name="spillsFileBufferSize">1k</property>

<property name="useStreamOutput">0</property>

<!--
单位为m
-->
<property name="systemReserveMemorySize">384m</property>

<!--是否采用zookeeper协调切换 -->
<property name="useZKSwitch">false</property>

<!-- XA Recovery Log日志路径 -->
<!--<property name="XARecoveryLogBaseDir">./</property>-->

<!-- XA Recovery Log日志名称 -->
<!--<property name="XARecoveryLogBaseName">tmlog</property>-->

</system>

<!-- 全局SQL防火墙设置 -->
<!--白名单可以使用通配符%或着*-->
<!--例如<host host="127.0.0.*" user="root"/>-->
<!--例如<host host="127.0.*" user="root"/>-->
<!--例如<host host="127.*" user="root"/>-->
<!--例如<host host="1*7.*" user="root"/>-->
<!--这些配置情况下对于127.0.0.1都能以root账户登录-->
<!--
<firewall>
<whitehost>
<host host="1*7.0.0.*" user="root"/>
</whitehost>
<blacklist check="false">
</blacklist>
</firewall>
-->

<user name="root" defaultAccount="true">
<property name="password">123456</property>
<property name="schemas">integration01</property>

<!-- 表级 DML 权限设置 -->
</user>

<user name="user">
<property name="password">user</property>
<property name="schemas">integration01</property>
<property name="readOnly">false</property>
</user>

</mycat:server>

[root@canal3 conf]# cat rule.xml
<?xml version="1.0" encoding="UTF-8"?>
<!-- - - Licensed under the Apache License, Version 2.0 (the "License");
- you may not use this file except in compliance with the License. - You
may obtain a copy of the License at - - http://www.apache.org/licenses/LICENSE-2.0
- - Unless required by applicable law or agreed to in writing, software -
distributed under the License is distributed on an "AS IS" BASIS, - WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - See the
License for the specific language governing permissions and - limitations
under the License. -->
<!DOCTYPE mycat:rule SYSTEM "rule.dtd">
<mycat:rule xmlns:mycat="http://io.mycat/">
<tableRule name="rule1">
<rule>
<columns>id</columns>
<algorithm>func1</algorithm>
</rule>
</tableRule>

<tableRule name="rule2">
<rule>
<columns>user_id</columns>
<algorithm>func1</algorithm>
</rule>
</tableRule>

<tableRule name="sharding-by-intfile">
<rule>
<columns>sharding_id</columns>
<algorithm>hash-int</algorithm>
</rule>
</tableRule>
<tableRule name="auto-sharding-long">
<rule>
<columns>id</columns>
<algorithm>rang-long</algorithm>
</rule>
</tableRule>
<tableRule name="mod-long">
<rule>
<columns>id</columns>


<algorithm>mod-long</algorithm>
</rule>
</tableRule>
<tableRule name="sharding-by-murmur">
<rule>
<columns>id</columns>
<algorithm>murmur</algorithm>
</rule>
</tableRule>
<tableRule name="crc32slot">
<rule>
<columns>id</columns>
<algorithm>crc32slot</algorithm>
</rule>
</tableRule>
<tableRule name="sharding-by-month">
<rule>
<columns>create_time</columns>
<algorithm>partbymonth</algorithm>
</rule>
</tableRule>
<tableRule name="latest-month-calldate">
<rule>
<columns>calldate</columns>
<algorithm>latestMonth</algorithm>
</rule>
</tableRule>

<tableRule name="auto-sharding-rang-mod">
<rule>
<columns>id</columns>
<algorithm>rang-mod</algorithm>
</rule>
</tableRule>

<tableRule name="jch">
<rule>
<columns>id</columns>
<algorithm>jump-consistent-hash</algorithm>
</rule>
</tableRule>

<function name="murmur"
class="io.mycat.route.function.PartitionByMurmurHash">
<property name="seed">0</property><!-- 默认是0 -->
<property name="count">2</property><!-- 要分片的数据库节点数量，必须指定，否则没法分片 -->
<property name="virtualBucketTimes">160</property><!-- 一个实际的数据库节点被映射为这么多虚拟节点，默认是160倍，也就是虚拟节点数是物理节点数的160倍 -->
<!-- <property name="weightMapFile">weightMapFile</property> 节点的权重，没有指定权重的节点默认是1。以properties文件的格式填写，以从0开始到count-1的整数值也就是节点索引为key，以节点权重值为值。所有权重值必须是正整数，否则以1代替 -->
<!-- <property name="bucketMapPath">/etc/mycat/bucketMapPath</property>
用于测试时观察各物理节点与虚拟节点的分布情况，如果指定了这个属性，会把虚拟节点的murmur hash值与物理节点的映射按行输出到这个文件，没有默认值，如果不指定，就不会输出任何东西 -->
</function>

<function name="crc32slot"
class="io.mycat.route.function.PartitionByCRC32PreSlot">
<property name="count">2</property><!-- 要分片的数据库节点数量，必须指定，否则没法分片 -->
</function>
<function name="hash-int"
class="io.mycat.route.function.PartitionByFileMap">
<property name="mapFile">partition-hash-int.txt</property>
</function>
<function name="rang-long"
class="io.mycat.route.function.AutoPartitionByLong">
<property name="mapFile">autopartition-long.txt</property>
</function>
<function name="mod-long" class="io.mycat.route.function.PartitionByMod">
<!-- how many data nodes -->
<property name="count">10</property>
</function>

<function name="func1" class="io.mycat.route.function.PartitionByLong">
<property name="partitionCount">8</property>
<property name="partitionLength">128</property>
</function>
<function name="latestMonth"
class="io.mycat.route.function.LatestMonthPartion">
<property name="splitOneDay">24</property>
</function>
<function name="partbymonth"
class="io.mycat.route.function.PartitionByMonth">
<property name="dateFormat">yyyy-MM-dd</property>
<property name="sBeginDate">2015-01-01</property>
</function>

<function name="rang-mod" class="io.mycat.route.function.PartitionByRangeMod">
<property name="mapFile">partition-range-mod.txt</property>
</function>

<function name="jump-consistent-hash" class="io.mycat.route.function.PartitionByJumpConsistentHash">
<property name="totalBuckets">3</property>
</function>
</mycat:rule>

4.查询分表

[root@canal3 ~]# mysql -uuser -puser -h10.40.20.44 -P8066 integration01
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.29-mycat-1.6.5-release-20180122220033 MyCat Server (OpenCloundDB)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type ‘help;‘ or ‘\h‘ for help. Type ‘\c‘ to clear the current input statement.

mysql> show tables;
+-------------------------+
| Tables in integration01 |
+-------------------------+
| user |
+-------------------------+
1 row in set (0.00 sec)

insert into user (id,borrow_nid,create_user,create_time,update_time) values(10,‘201802051008610‘,‘dba‘,now(),now());
insert into user (id,borrow_nid,create_user,create_time,update_time) values(11,‘201802051008611‘,‘dba‘,now(),now());
insert into user (id,borrow_nid,create_user,create_time,update_time) values(12,‘201802051008612‘,‘dba‘,now(),now());
insert into user (id,borrow_nid,create_user,create_time,update_time) values(13,‘201802051008613‘,‘dba‘,now(),now());
insert into user (id,borrow_nid,create_user,create_time,update_time) values(14,‘201802051008614‘,‘dba‘,now(),now());
insert into user (id,borrow_nid,create_user,create_time,update_time) values(15,‘201802051008615‘,‘dba‘,now(),now());
insert into user (id,borrow_nid,create_user,create_time,update_time) values(16,‘201802051008616‘,‘dba‘,now(),now());
insert into user (id,borrow_nid,create_user,create_time,update_time) values(17,‘201802051008617‘,‘dba‘,now(),now());
insert into user (id,borrow_nid,create_user,create_time,update_time) values(18,‘201802051008618‘,‘dba‘,now(),now());
insert into user (id,borrow_nid,create_user,create_time,update_time) values(19,‘201802051008619‘,‘dba‘,now(),now());
insert into user (id,borrow_nid,create_user,create_time,update_time) values(20,‘201802051008620‘,‘dba‘,now(),now());
insert into user (id,borrow_nid,create_user,create_time,update_time) values(21,‘201802051008621‘,‘dba‘,now(),now());
insert into user (id,borrow_nid,create_user,create_time,update_time) values(22,‘201802051008622‘,‘dba‘,now(),now());
insert into user (id,borrow_nid,create_user,create_time,update_time) values(23,‘201802051008623‘,‘dba‘,now(),now());

mysql> explain select * from user;
+-----------+--------------------------------+
| DATA_NODE | SQL |
+-----------+--------------------------------+
| dn1 | SELECT * FROM user1 LIMIT 100 |
| dn1 | SELECT * FROM user10 LIMIT 100 |
| dn1 | SELECT * FROM user2 LIMIT 100 |
| dn1 | SELECT * FROM user3 LIMIT 100 |
| dn1 | SELECT * FROM user4 LIMIT 100 |
| dn1 | SELECT * FROM user5 LIMIT 100 |
| dn1 | SELECT * FROM user6 LIMIT 100 |
| dn1 | SELECT * FROM user7 LIMIT 100 |
| dn1 | SELECT * FROM user8 LIMIT 100 |
| dn1 | SELECT * FROM user9 LIMIT 100 |
+-----------+--------------------------------+